Chapter 17. Using Precision Time Protocol (PTP) hardware
You can configure linuxptp
services and use PTP-capable hardware in OpenShift Container Platform cluster nodes.
17.1. About PTP hardware
You can use the OpenShift Container Platform console or OpenShift CLI (oc
) to install PTP by deploying the PTP Operator. The PTP Operator creates and manages the linuxptp
services and provides the following features:
- Discovery of the PTP-capable devices in the cluster.
-
Management of the configuration of
linuxptp
services. -
Notification of PTP clock events that negatively affect the performance and reliability of your application with the PTP Operator
cloud-event-proxy
sidecar.
The PTP Operator works with PTP-capable devices on clusters provisioned only on bare-metal infrastructure.
17.2. About PTP
Precision Time Protocol (PTP) is used to synchronize clocks in a network. When used in conjunction with hardware support, PTP is capable of sub-microsecond accuracy, and is more accurate than Network Time Protocol (NTP).
17.2.1. Elements of a PTP domain
PTP is used to synchronize multiple nodes connected in a network, with clocks for each node. The clocks synchronized by PTP are organized in a source-destination hierarchy. The hierarchy is created and updated automatically by the best master clock (BMC) algorithm, which runs on every clock. Destination clocks are synchronized to source clocks, and destination clocks can themselves be the source for other downstream clocks. The three primary types of PTP clocks are described below.
- Grandmaster clock
- The grandmaster clock provides standard time information to other clocks across the network and ensures accurate and stable synchronisation. It writes time stamps and responds to time requests from other clocks. Grandmaster clocks synchronize to a Global Navigation Satellite System (GNSS) time source. The Grandmaster clock is the authoritative source of time in the network and is responsible for providing time synchronization to all other devices.
- Ordinary clock
- The ordinary clock has a single port connection that can play the role of source or destination clock, depending on its position in the network. The ordinary clock can read and write time stamps.
- Boundary clock
- The boundary clock has ports in two or more communication paths and can be a source and a destination to other destination clocks at the same time. The boundary clock works as a destination clock upstream. The destination clock receives the timing message, adjusts for delay, and then creates a new source time signal to pass down the network. The boundary clock produces a new timing packet that is still correctly synced with the source clock and can reduce the number of connected devices reporting directly to the source clock.
17.2.2. Advantages of PTP over NTP
One of the main advantages that PTP has over NTP is the hardware support present in various network interface controllers (NIC) and network switches. The specialized hardware allows PTP to account for delays in message transfer and improves the accuracy of time synchronization. To achieve the best possible accuracy, it is recommended that all networking components between PTP clocks are PTP hardware enabled.
Hardware-based PTP provides optimal accuracy, since the NIC can time stamp the PTP packets at the exact moment they are sent and received. Compare this to software-based PTP, which requires additional processing of the PTP packets by the operating system.
Before enabling PTP, ensure that NTP is disabled for the required nodes. You can disable the chrony time service (chronyd
) using a MachineConfig
custom resource. For more information, see Disabling chrony time service.
17.2.3. Using PTP with dual NIC hardware
OpenShift Container Platform supports single and dual NIC hardware for precision PTP timing in the cluster.
For 5G telco networks that deliver mid-band spectrum coverage, each virtual distributed unit (vDU) requires connections to 6 radio units (RUs). To make these connections, each vDU host requires 2 NICs configured as boundary clocks.
Dual NIC hardware allows you to connect each NIC to the same upstream leader clock with separate ptp4l
instances for each NIC feeding the downstream clocks.
17.3. Overview of linuxptp in OpenShift Container Platform nodes
OpenShift Container Platform uses PTP and linuxptp
for high precision system timing in bare-metal infrastructure. The linuxptp
package includes the ts2phc
, pmc
, ptp4l
, and phc2sys
programs for system clock synchronization.
- ts2phc
ts2phc
synchronizes the PTP hardware clock (PHC) across PTP devices with a high degree of precision.ts2phc
is used in grandmaster clock configurations. It receives the precision timing signal a high precision clock source such as Global Navigation Satellite System (GNSS). GNSS provides an accurate and reliable source of synchronized time for use in large distributed networks. GNSS clocks typically provide time information with a precision of a few nanoseconds.The
ts2phc
system daemon sends timing information from the grandmaster clock to other PTP devices in the network by reading time information from the grandmaster clock and converting it to PHC format. PHC time is used by other devices in the network to synchronize their clocks with the grandmaster clock.- pmc
-
pmc
implements a PTP management client (pmc
) according to IEEE standard 1588.1588.pmc
provides basic management access for theptp4l
system daemon.pmc
reads from standard input and sends the output over the selected transport, printing any replies it receives. - ptp4l
ptp4l
implements the PTP boundary clock and ordinary clock and runs as a system daemon.ptp4l
does the following:- Synchronizes the PHC to the source clock with hardware time stamping
- Synchronizes the system clock to the source clock with software time stamping
- phc2sys
-
phc2sys
synchronizes the system clock to the PHC on the network interface controller (NIC). Thephc2sys
system daemon continuously monitors the PHC for timing information. When it detects a timing error, the PHC corrects the system clock.
17.4. Installing the PTP Operator using the CLI
As a cluster administrator, you can install the Operator by using the CLI.
Prerequisites
- A cluster installed on bare-metal hardware with nodes that have hardware that supports PTP.
-
Install the OpenShift CLI (
oc
). -
Log in as a user with
cluster-admin
privileges.
Procedure
Create a namespace for the PTP Operator.
Save the following YAML in the
ptp-namespace.yaml
file:apiVersion: v1 kind: Namespace metadata: name: openshift-ptp annotations: workload.openshift.io/allowed: management labels: name: openshift-ptp openshift.io/cluster-monitoring: "true"
Create the
Namespace
CR:$ oc create -f ptp-namespace.yaml
Create an Operator group for the PTP Operator.
Save the following YAML in the
ptp-operatorgroup.yaml
file:apiVersion: operators.coreos.com/v1 kind: OperatorGroup metadata: name: ptp-operators namespace: openshift-ptp spec: targetNamespaces: - openshift-ptp
Create the
OperatorGroup
CR:$ oc create -f ptp-operatorgroup.yaml
Subscribe to the PTP Operator.
Save the following YAML in the
ptp-sub.yaml
file:apiVersion: operators.coreos.com/v1alpha1 kind: Subscription metadata: name: ptp-operator-subscription namespace: openshift-ptp spec: channel: "stable" name: ptp-operator source: redhat-operators sourceNamespace: openshift-marketplace
Create the
Subscription
CR:$ oc create -f ptp-sub.yaml
To verify that the Operator is installed, enter the following command:
$ oc get csv -n openshift-ptp -o custom-columns=Name:.metadata.name,Phase:.status.phase
Example output
Name Phase 4.13.0-202301261535 Succeeded
17.5. Installing the PTP Operator using the web console
As a cluster administrator, you can install the PTP Operator using the web console.
You have to create the namespace and Operator group as mentioned in the previous section.
Procedure
Install the PTP Operator using the OpenShift Container Platform web console:
-
In the OpenShift Container Platform web console, click Operators
OperatorHub. - Choose PTP Operator from the list of available Operators, and then click Install.
- On the Install Operator page, under A specific namespace on the cluster select openshift-ptp. Then, click Install.
-
In the OpenShift Container Platform web console, click Operators
Optional: Verify that the PTP Operator installed successfully:
-
Switch to the Operators
Installed Operators page. Ensure that PTP Operator is listed in the openshift-ptp project with a Status of InstallSucceeded.
NoteDuring installation an Operator might display a Failed status. If the installation later succeeds with an InstallSucceeded message, you can ignore the Failed message.
If the Operator does not appear as installed, to troubleshoot further:
-
Go to the Operators
Installed Operators page and inspect the Operator Subscriptions and Install Plans tabs for any failure or errors under Status. -
Go to the Workloads
Pods page and check the logs for pods in the openshift-ptp
project.
-
Go to the Operators
-
Switch to the Operators
17.6. Configuring PTP devices
The PTP Operator adds the NodePtpDevice.ptp.openshift.io
custom resource definition (CRD) to OpenShift Container Platform.
When installed, the PTP Operator searches your cluster for PTP-capable network devices on each node. It creates and updates a NodePtpDevice
custom resource (CR) object for each node that provides a compatible PTP-capable network device.
17.6.1. Discovering PTP-capable network devices in your cluster
Identify PTP-capable network devices that exist in your cluster so that you can configure them
Prerequisties
- You installed the PTP Operator.
Procedure
To return a complete list of PTP capable network devices in your cluster, run the following command:
$ oc get NodePtpDevice -n openshift-ptp -o yaml
Example output
apiVersion: v1 items: - apiVersion: ptp.openshift.io/v1 kind: NodePtpDevice metadata: creationTimestamp: "2022-01-27T15:16:28Z" generation: 1 name: dev-worker-0 1 namespace: openshift-ptp resourceVersion: "6538103" uid: d42fc9ad-bcbf-4590-b6d8-b676c642781a spec: {} status: devices: 2 - name: eno1 - name: eno2 - name: eno3 - name: eno4 - name: enp5s0f0 - name: enp5s0f1 ...
17.6.2. Configuring linuxptp services as a grandmaster clock
You can configure the linuxptp
services (ptp4l
, phc2sys
, ts2phc
) as a grandmaster clock (T-GM) by creating a PtpConfig
custom resource (CR) that configures the host NIC.
The ts2phc
utility allows you to synchronize the system clock with the PTP grandmaster clock so that the node can stream precision clock signal to downstream PTP ordinary clocks and boundary clocks.
Use the following example PtpConfig
CR as the basis to configure linuxptp
services as the grandmaster clock for your particular hardware and environment. This example CR does not configure PTP fast events. To configure PTP fast events, set appropriate values for ptp4lOpts
, ptp4lConf
, and ptpClockThreshold
. ptpClockThreshold
is used only when events are enabled. See "Configuring the PTP fast event notifications publisher" for more information.
Prerequisites
- For T-GM clocks in production environments, install an Intel E810 Westport Channel NIC in the bare-metal cluster host.
-
Install the OpenShift CLI (
oc
). -
Log in as a user with
cluster-admin
privileges. - Install the PTP Operator.
Procedure
Create the
PtpConfig
resource. For example:Depending on your requirements, use one of the following T-GM configurations for your deployment. Save the YAML in the
grandmaster-clock-ptp-config.yaml
file:Example 17.1. Example PTP grandmaster clock configuration
apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: grandmaster-clock namespace: openshift-ptp annotations: {} spec: profile: - name: grandmaster-clock # The interface name is hardware-specific interface: $interface ptp4lOpts: "-2" phc2sysOpts: "-a -r -r -n 24" ptpSchedulingPolicy: SCHED_FIFO ptpSchedulingPriority: 10 ptpSettings: logReduce: "true" ptp4lConf: | [global] # # Default Data Set # twoStepFlag 1 slaveOnly 0 priority1 128 priority2 128 domainNumber 24 #utc_offset 37 clockClass 255 clockAccuracy 0xFE offsetScaledLogVariance 0xFFFF free_running 0 freq_est_interval 1 dscp_event 0 dscp_general 0 dataset_comparison G.8275.x G.8275.defaultDS.localPriority 128 # # Port Data Set # logAnnounceInterval -3 logSyncInterval -4 logMinDelayReqInterval -4 logMinPdelayReqInterval -4 announceReceiptTimeout 3 syncReceiptTimeout 0 delayAsymmetry 0 fault_reset_interval -4 neighborPropDelayThresh 20000000 masterOnly 0 G.8275.portDS.localPriority 128 # # Run time options # assume_two_step 0 logging_level 6 path_trace_enabled 0 follow_up_info 0 hybrid_e2e 0 inhibit_multicast_service 0 net_sync_monitor 0 tc_spanning_tree 0 tx_timestamp_timeout 50 unicast_listen 0 unicast_master_table 0 unicast_req_duration 3600 use_syslog 1 verbose 0 summary_interval 0 kernel_leap 1 check_fup_sync 0 clock_class_threshold 7 # # Servo Options # pi_proportional_const 0.0 pi_integral_const 0.0 pi_proportional_scale 0.0 pi_proportional_exponent -0.3 pi_proportional_norm_max 0.7 pi_integral_scale 0.0 pi_integral_exponent 0.4 pi_integral_norm_max 0.3 step_threshold 2.0 first_step_threshold 0.00002 max_frequency 900000000 clock_servo pi sanity_freq_limit 200000000 ntpshm_segment 0 # # Transport options # transportSpecific 0x0 ptp_dst_mac 01:1B:19:00:00:00 p2p_dst_mac 01:80:C2:00:00:0E udp_ttl 1 udp6_scope 0x0E uds_address /var/run/ptp4l # # Default interface options # clock_type OC network_transport L2 delay_mechanism E2E time_stamping hardware tsproc_mode filter delay_filter moving_median delay_filter_length 10 egressLatency 0 ingressLatency 0 boundary_clock_jbod 0 # # Clock description # productDescription ;; revisionData ;; manufacturerIdentity 00:00:00 userDescription ; timeSource 0xA0 recommend: - profile: grandmaster-clock priority: 4 match: - nodeLabel: "node-role.kubernetes.io/$mcp"
NoteThe example PTP grandmaster clock configuration is for test purposes only and is not intended for production.
Example 17.2. PTP grandmaster clock configuration for E810 NIC
apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: grandmaster namespace: openshift-ptp annotations: ran.openshift.io/ztp-deploy-wave: "10" spec: profile: - name: "grandmaster" ptp4lOpts: "-2 --summary_interval -4" phc2sysOpts: -r -u 0 -m -O -37 -N 8 -R 16 -s $iface_master -n 24 ptpSchedulingPolicy: SCHED_FIFO ptpSchedulingPriority: 10 ptpSettings: logReduce: "true" plugins: e810: enableDefaultConfig: true ts2phcOpts: " " ts2phcConf: | [nmea] ts2phc.master 1 [global] use_syslog 0 verbose 1 logging_level 7 ts2phc.pulsewidth 100000000 ts2phc.nmea_serialport $gnss_serialport leapfile /usr/share/zoneinfo/leap-seconds.list [$iface_master] ts2phc.extts_polarity rising ts2phc.extts_correction 0 ptp4lConf: | [$iface_master] masterOnly 1 [$iface_master_1] masterOnly 1 [$iface_master_2] masterOnly 1 [$iface_master_3] masterOnly 1 [global] # # Default Data Set # twoStepFlag 1 priority1 128 priority2 128 domainNumber 24 #utc_offset 37 clockClass 6 clockAccuracy 0x27 offsetScaledLogVariance 0xFFFF free_running 0 freq_est_interval 1 dscp_event 0 dscp_general 0 dataset_comparison G.8275.x G.8275.defaultDS.localPriority 128 # # Port Data Set # logAnnounceInterval -3 logSyncInterval -4 logMinDelayReqInterval -4 logMinPdelayReqInterval 0 announceReceiptTimeout 3 syncReceiptTimeout 0 delayAsymmetry 0 fault_reset_interval -4 neighborPropDelayThresh 20000000 masterOnly 0 G.8275.portDS.localPriority 128 # # Run time options # assume_two_step 0 logging_level 6 path_trace_enabled 0 follow_up_info 0 hybrid_e2e 0 inhibit_multicast_service 0 net_sync_monitor 0 tc_spanning_tree 0 tx_timestamp_timeout 50 unicast_listen 0 unicast_master_table 0 unicast_req_duration 3600 use_syslog 1 verbose 0 summary_interval -4 kernel_leap 1 check_fup_sync 0 clock_class_threshold 7 # # Servo Options # pi_proportional_const 0.0 pi_integral_const 0.0 pi_proportional_scale 0.0 pi_proportional_exponent -0.3 pi_proportional_norm_max 0.7 pi_integral_scale 0.0 pi_integral_exponent 0.4 pi_integral_norm_max 0.3 step_threshold 2.0 first_step_threshold 0.00002 clock_servo pi sanity_freq_limit 200000000 ntpshm_segment 0 # # Transport options # transportSpecific 0x0 ptp_dst_mac 01:1B:19:00:00:00 p2p_dst_mac 01:80:C2:00:00:0E udp_ttl 1 udp6_scope 0x0E uds_address /var/run/ptp4l # # Default interface options # clock_type BC network_transport L2 delay_mechanism E2E time_stamping hardware tsproc_mode filter delay_filter moving_median delay_filter_length 10 egressLatency 0 ingressLatency 0 boundary_clock_jbod 0 # # Clock description # productDescription ;; revisionData ;; manufacturerIdentity 00:00:00 userDescription ; timeSource 0x20 recommend: - profile: "grandmaster" priority: 4 match: - nodeLabel: "node-role.kubernetes.io/$mcp"
Create the CR by running the following command:
$ oc create -f grandmaster-clock-ptp-config.yaml
Verification
Check that the
PtpConfig
profile is applied to the node.Get the list of pods in the
openshift-ptp
namespace by running the following command:$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-74m2g 3/3 Running 3 4d15h 10.16.230.7 compute-1.example.com ptp-operator-5f4f48d7c-x7zkf 1/1 Running 1 4d15h 10.128.1.145 compute-1.example.com
Check that the profile is correct. Examine the logs of the
linuxptp
daemon that corresponds to the node you specified in thePtpConfig
profile. Run the following command:$ oc logs linuxptp-daemon-74m2g -n openshift-ptp -c linuxptp-daemon-container
Example output
ts2phc[94980.334]: [ts2phc.0.config] nmea delay: 98690975 ns ts2phc[94980.334]: [ts2phc.0.config] ens3f0 extts index 0 at 1676577329.999999999 corr 0 src 1676577330.901342528 diff -1 ts2phc[94980.334]: [ts2phc.0.config] ens3f0 master offset -1 s2 freq -1 ts2phc[94980.441]: [ts2phc.0.config] nmea sentence: GNRMC,195453.00,A,4233.24427,N,07126.64420,W,0.008,,160223,,,A,V phc2sys[94980.450]: [ptp4l.0.config] CLOCK_REALTIME phc offset 943 s2 freq -89604 delay 504 phc2sys[94980.512]: [ptp4l.0.config] CLOCK_REALTIME phc offset 1000 s2 freq -89264 delay 474
Additional resources
17.6.2.1. Grandmaster clock PtpConfig configuration reference
The following reference information describes the configuration options for the PtpConfig
custom resource (CR) that configures the linuxptp
services (ptp4l
, phc2sys
, ts2phc
) as a grandmaster clock.
PtpConfig CR field | Description |
---|---|
|
Specify an array of
The plugin mechanism allows the PTP Operator to do automated hardware configuration. For the Intel Westport Channel NIC, when |
|
Specify system configuration options for the |
|
Specify the required configuration to start |
| Specify the maximum amount of time to wait for the transmit (TX) timestamp from the sender before discarding the data. |
| Specify the JBOD boundary clock time delay value. This value is used to correct the time values that are passed between the network time devices. |
|
Specify system config options for the Note
Ensure that the network interface listed here is configured as grandmaster and is referenced as required in the |
|
Configure the scheduling policy for |
|
Set an integer value from 1-65 to configure FIFO priority for |
|
Optional. If |
|
Sets the configuration for the
|
|
Set options for the |
|
Specify an array of one or more |
|
Specify the |
|
Specify the |
|
Specify |
|
Set |
|
Set |
17.6.3. Configuring linuxptp services as an ordinary clock
You can configure linuxptp
services (ptp4l
, phc2sys
) as ordinary clock by creating a PtpConfig
custom resource (CR) object.
Use the following example PtpConfig
CR as the basis to configure linuxptp
services as an ordinary clock for your particular hardware and environment. This example CR does not configure PTP fast events. To configure PTP fast events, set appropriate values for ptp4lOpts
, ptp4lConf
, and ptpClockThreshold
. ptpClockThreshold
is required only when events are enabled. See "Configuring the PTP fast event notifications publisher" for more information.
Prerequisites
-
Install the OpenShift CLI (
oc
). -
Log in as a user with
cluster-admin
privileges. - Install the PTP Operator.
Procedure
Create the following
PtpConfig
CR, and then save the YAML in theordinary-clock-ptp-config.yaml
file.Example PTP ordinary clock configuration
apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: ordinary-clock namespace: openshift-ptp annotations: {} spec: profile: - name: ordinary-clock # The interface name is hardware-specific interface: $interface ptp4lOpts: "-2 -s" phc2sysOpts: "-a -r -n 24" ptpSchedulingPolicy: SCHED_FIFO ptpSchedulingPriority: 10 ptpSettings: logReduce: "true" ptp4lConf: | [global] # # Default Data Set # twoStepFlag 1 slaveOnly 1 priority1 128 priority2 128 domainNumber 24 #utc_offset 37 clockClass 255 clockAccuracy 0xFE offsetScaledLogVariance 0xFFFF free_running 0 freq_est_interval 1 dscp_event 0 dscp_general 0 dataset_comparison G.8275.x G.8275.defaultDS.localPriority 128 # # Port Data Set # logAnnounceInterval -3 logSyncInterval -4 logMinDelayReqInterval -4 logMinPdelayReqInterval -4 announceReceiptTimeout 3 syncReceiptTimeout 0 delayAsymmetry 0 fault_reset_interval -4 neighborPropDelayThresh 20000000 masterOnly 0 G.8275.portDS.localPriority 128 # # Run time options # assume_two_step 0 logging_level 6 path_trace_enabled 0 follow_up_info 0 hybrid_e2e 0 inhibit_multicast_service 0 net_sync_monitor 0 tc_spanning_tree 0 tx_timestamp_timeout 50 unicast_listen 0 unicast_master_table 0 unicast_req_duration 3600 use_syslog 1 verbose 0 summary_interval 0 kernel_leap 1 check_fup_sync 0 clock_class_threshold 7 # # Servo Options # pi_proportional_const 0.0 pi_integral_const 0.0 pi_proportional_scale 0.0 pi_proportional_exponent -0.3 pi_proportional_norm_max 0.7 pi_integral_scale 0.0 pi_integral_exponent 0.4 pi_integral_norm_max 0.3 step_threshold 2.0 first_step_threshold 0.00002 max_frequency 900000000 clock_servo pi sanity_freq_limit 200000000 ntpshm_segment 0 # # Transport options # transportSpecific 0x0 ptp_dst_mac 01:1B:19:00:00:00 p2p_dst_mac 01:80:C2:00:00:0E udp_ttl 1 udp6_scope 0x0E uds_address /var/run/ptp4l # # Default interface options # clock_type OC network_transport L2 delay_mechanism E2E time_stamping hardware tsproc_mode filter delay_filter moving_median delay_filter_length 10 egressLatency 0 ingressLatency 0 boundary_clock_jbod 0 # # Clock description # productDescription ;; revisionData ;; manufacturerIdentity 00:00:00 userDescription ; timeSource 0xA0 recommend: - profile: ordinary-clock priority: 4 match: - nodeLabel: "node-role.kubernetes.io/$mcp"
Table 17.2. PTP ordinary clock CR configuration options Custom resource field Description name
The name of the
PtpConfig
CR.profile
Specify an array of one or more
profile
objects. Each profile must be uniquely named.interface
Specify the network interface to be used by the
ptp4l
service, for exampleens787f1
.ptp4lOpts
Specify system config options for the
ptp4l
service, for example-2
to select the IEEE 802.3 network transport. The options should not include the network interface name-i <interface>
and service config file-f /etc/ptp4l.conf
because the network interface name and the service config file are automatically appended. Append--summary_interval -4
to use PTP fast events with this interface.phc2sysOpts
Specify system config options for the
phc2sys
service. If this field is empty, the PTP Operator does not start thephc2sys
service. For Intel Columbiaville 800 Series NICs, setphc2sysOpts
options to-a -r -m -n 24 -N 8 -R 16
.-m
prints messages tostdout
. Thelinuxptp-daemon
DaemonSet
parses the logs and generates Prometheus metrics.ptp4lConf
Specify a string that contains the configuration to replace the default
/etc/ptp4l.conf
file. To use the default configuration, leave the field empty.tx_timestamp_timeout
For Intel Columbiaville 800 Series NICs, set
tx_timestamp_timeout
to50
.boundary_clock_jbod
For Intel Columbiaville 800 Series NICs, set
boundary_clock_jbod
to0
.ptpSchedulingPolicy
Scheduling policy for
ptp4l
andphc2sys
processes. Default value isSCHED_OTHER
. UseSCHED_FIFO
on systems that support FIFO scheduling.ptpSchedulingPriority
Integer value from 1-65 used to set FIFO priority for
ptp4l
andphc2sys
processes whenptpSchedulingPolicy
is set toSCHED_FIFO
. TheptpSchedulingPriority
field is not used whenptpSchedulingPolicy
is set toSCHED_OTHER
.ptpClockThreshold
Optional. If
ptpClockThreshold
is not present, default values are used for theptpClockThreshold
fields.ptpClockThreshold
configures how long after the PTP master clock is disconnected before PTP events are triggered.holdOverTimeout
is the time value in seconds before the PTP clock event state changes toFREERUN
when the PTP master clock is disconnected. ThemaxOffsetThreshold
andminOffsetThreshold
settings configure offset values in nanoseconds that compare against the values forCLOCK_REALTIME
(phc2sys
) or master offset (ptp4l
). When theptp4l
orphc2sys
offset value is outside this range, the PTP clock state is set toFREERUN
. When the offset value is within this range, the PTP clock state is set toLOCKED
.recommend
Specify an array of one or more
recommend
objects that define rules on how theprofile
should be applied to nodes..recommend.profile
Specify the
.recommend.profile
object name defined in theprofile
section..recommend.priority
Set
.recommend.priority
to0
for ordinary clock..recommend.match
Specify
.recommend.match
rules withnodeLabel
ornodeName
values..recommend.match.nodeLabel
Set
nodeLabel
with thekey
of thenode.Labels
field from the node object by using theoc get nodes --show-labels
command. For example,node-role.kubernetes.io/worker
..recommend.match.nodeName
Set
nodeName
with the value of thenode.Name
field from the node object by using theoc get nodes
command. For example,compute-1.example.com
.Create the
PtpConfig
CR by running the following command:$ oc create -f ordinary-clock-ptp-config.yaml
Verification
Check that the
PtpConfig
profile is applied to the node.Get the list of pods in the
openshift-ptp
namespace by running the following command:$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-4xkbb 1/1 Running 0 43m 10.1.196.24 compute-0.example.com linuxptp-daemon-tdspf 1/1 Running 0 43m 10.1.196.25 compute-1.example.com ptp-operator-657bbb64c8-2f8sj 1/1 Running 0 43m 10.129.0.61 control-plane-1.example.com
Check that the profile is correct. Examine the logs of the
linuxptp
daemon that corresponds to the node you specified in thePtpConfig
profile. Run the following command:$ oc logs linuxptp-daemon-4xkbb -n openshift-ptp -c linuxptp-daemon-container
Example output
I1115 09:41:17.117596 4143292 daemon.go:107] in applyNodePTPProfile I1115 09:41:17.117604 4143292 daemon.go:109] updating NodePTPProfile to: I1115 09:41:17.117607 4143292 daemon.go:110] ------------------------------------ I1115 09:41:17.117612 4143292 daemon.go:102] Profile Name: profile1 I1115 09:41:17.117616 4143292 daemon.go:102] Interface: ens787f1 I1115 09:41:17.117620 4143292 daemon.go:102] Ptp4lOpts: -2 -s I1115 09:41:17.117623 4143292 daemon.go:102] Phc2sysOpts: -a -r -n 24 I1115 09:41:17.117626 4143292 daemon.go:116] ------------------------------------
Additional resources
- For more information about FIFO priority scheduling on PTP hardware, see Configuring FIFO priority scheduling for PTP hardware.
- For more information about configuring PTP fast events, see Configuring the PTP fast event notifications publisher.
17.6.4. Configuring linuxptp services as a boundary clock
You can configure the linuxptp
services (ptp4l
, phc2sys
) as boundary clock by creating a PtpConfig
custom resource (CR) object.
Use the following example PtpConfig
CR as the basis to configure linuxptp
services as the boundary clock for your particular hardware and environment. This example CR does not configure PTP fast events. To configure PTP fast events, set appropriate values for ptp4lOpts
, ptp4lConf
, and ptpClockThreshold
. ptpClockThreshold
is used only when events are enabled. See "Configuring the PTP fast event notifications publisher" for more information.
Prerequisites
-
Install the OpenShift CLI (
oc
). -
Log in as a user with
cluster-admin
privileges. - Install the PTP Operator.
Procedure
Create the following
PtpConfig
CR, and then save the YAML in theboundary-clock-ptp-config.yaml
file.Example PTP boundary clock configuration
apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: boundary-clock namespace: openshift-ptp annotations: {} spec: profile: - name: boundary-clock ptp4lOpts: "-2" phc2sysOpts: "-a -r -n 24" ptpSchedulingPolicy: SCHED_FIFO ptpSchedulingPriority: 10 ptpSettings: logReduce: "true" ptp4lConf: | # The interface name is hardware-specific [$iface_slave] masterOnly 0 [$iface_master_1] masterOnly 1 [$iface_master_2] masterOnly 1 [$iface_master_3] masterOnly 1 [global] # # Default Data Set # twoStepFlag 1 slaveOnly 0 priority1 128 priority2 128 domainNumber 24 #utc_offset 37 clockClass 248 clockAccuracy 0xFE offsetScaledLogVariance 0xFFFF free_running 0 freq_est_interval 1 dscp_event 0 dscp_general 0 dataset_comparison G.8275.x G.8275.defaultDS.localPriority 128 # # Port Data Set # logAnnounceInterval -3 logSyncInterval -4 logMinDelayReqInterval -4 logMinPdelayReqInterval -4 announceReceiptTimeout 3 syncReceiptTimeout 0 delayAsymmetry 0 fault_reset_interval -4 neighborPropDelayThresh 20000000 masterOnly 0 G.8275.portDS.localPriority 128 # # Run time options # assume_two_step 0 logging_level 6 path_trace_enabled 0 follow_up_info 0 hybrid_e2e 0 inhibit_multicast_service 0 net_sync_monitor 0 tc_spanning_tree 0 tx_timestamp_timeout 50 unicast_listen 0 unicast_master_table 0 unicast_req_duration 3600 use_syslog 1 verbose 0 summary_interval 0 kernel_leap 1 check_fup_sync 0 clock_class_threshold 135 # # Servo Options # pi_proportional_const 0.0 pi_integral_const 0.0 pi_proportional_scale 0.0 pi_proportional_exponent -0.3 pi_proportional_norm_max 0.7 pi_integral_scale 0.0 pi_integral_exponent 0.4 pi_integral_norm_max 0.3 step_threshold 2.0 first_step_threshold 0.00002 max_frequency 900000000 clock_servo pi sanity_freq_limit 200000000 ntpshm_segment 0 # # Transport options # transportSpecific 0x0 ptp_dst_mac 01:1B:19:00:00:00 p2p_dst_mac 01:80:C2:00:00:0E udp_ttl 1 udp6_scope 0x0E uds_address /var/run/ptp4l # # Default interface options # clock_type BC network_transport L2 delay_mechanism E2E time_stamping hardware tsproc_mode filter delay_filter moving_median delay_filter_length 10 egressLatency 0 ingressLatency 0 boundary_clock_jbod 0 # # Clock description # productDescription ;; revisionData ;; manufacturerIdentity 00:00:00 userDescription ; timeSource 0xA0 recommend: - profile: boundary-clock priority: 4 match: - nodeLabel: "node-role.kubernetes.io/$mcp"
Table 17.3. PTP boundary clock CR configuration options Custom resource field Description name
The name of the
PtpConfig
CR.profile
Specify an array of one or more
profile
objects.name
Specify the name of a profile object which uniquely identifies a profile object.
ptp4lOpts
Specify system config options for the
ptp4l
service. The options should not include the network interface name-i <interface>
and service config file-f /etc/ptp4l.conf
because the network interface name and the service config file are automatically appended.ptp4lConf
Specify the required configuration to start
ptp4l
as boundary clock. For example,ens1f0
synchronizes from a grandmaster clock andens1f3
synchronizes connected devices.<interface_1>
The interface that receives the synchronization clock.
<interface_2>
The interface that sends the synchronization clock.
tx_timestamp_timeout
For Intel Columbiaville 800 Series NICs, set
tx_timestamp_timeout
to50
.boundary_clock_jbod
For Intel Columbiaville 800 Series NICs, ensure
boundary_clock_jbod
is set to0
. For Intel Fortville X710 Series NICs, ensureboundary_clock_jbod
is set to1
.phc2sysOpts
Specify system config options for the
phc2sys
service. If this field is empty, the PTP Operator does not start thephc2sys
service.ptpSchedulingPolicy
Scheduling policy for ptp4l and phc2sys processes. Default value is
SCHED_OTHER
. UseSCHED_FIFO
on systems that support FIFO scheduling.ptpSchedulingPriority
Integer value from 1-65 used to set FIFO priority for
ptp4l
andphc2sys
processes whenptpSchedulingPolicy
is set toSCHED_FIFO
. TheptpSchedulingPriority
field is not used whenptpSchedulingPolicy
is set toSCHED_OTHER
.ptpClockThreshold
Optional. If
ptpClockThreshold
is not present, default values are used for theptpClockThreshold
fields.ptpClockThreshold
configures how long after the PTP master clock is disconnected before PTP events are triggered.holdOverTimeout
is the time value in seconds before the PTP clock event state changes toFREERUN
when the PTP master clock is disconnected. ThemaxOffsetThreshold
andminOffsetThreshold
settings configure offset values in nanoseconds that compare against the values forCLOCK_REALTIME
(phc2sys
) or master offset (ptp4l
). When theptp4l
orphc2sys
offset value is outside this range, the PTP clock state is set toFREERUN
. When the offset value is within this range, the PTP clock state is set toLOCKED
.recommend
Specify an array of one or more
recommend
objects that define rules on how theprofile
should be applied to nodes..recommend.profile
Specify the
.recommend.profile
object name defined in theprofile
section..recommend.priority
Specify the
priority
with an integer value between0
and99
. A larger number gets lower priority, so a priority of99
is lower than a priority of10
. If a node can be matched with multiple profiles according to rules defined in thematch
field, the profile with the higher priority is applied to that node..recommend.match
Specify
.recommend.match
rules withnodeLabel
ornodeName
values..recommend.match.nodeLabel
Set
nodeLabel
with thekey
of thenode.Labels
field from the node object by using theoc get nodes --show-labels
command. For example,node-role.kubernetes.io/worker
..recommend.match.nodeName
Set
nodeName
with the value of thenode.Name
field from the node object by using theoc get nodes
command. For example,compute-1.example.com
.Create the CR by running the following command:
$ oc create -f boundary-clock-ptp-config.yaml
Verification
Check that the
PtpConfig
profile is applied to the node.Get the list of pods in the
openshift-ptp
namespace by running the following command:$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-4xkbb 1/1 Running 0 43m 10.1.196.24 compute-0.example.com linuxptp-daemon-tdspf 1/1 Running 0 43m 10.1.196.25 compute-1.example.com ptp-operator-657bbb64c8-2f8sj 1/1 Running 0 43m 10.129.0.61 control-plane-1.example.com
Check that the profile is correct. Examine the logs of the
linuxptp
daemon that corresponds to the node you specified in thePtpConfig
profile. Run the following command:$ oc logs linuxptp-daemon-4xkbb -n openshift-ptp -c linuxptp-daemon-container
Example output
I1115 09:41:17.117596 4143292 daemon.go:107] in applyNodePTPProfile I1115 09:41:17.117604 4143292 daemon.go:109] updating NodePTPProfile to: I1115 09:41:17.117607 4143292 daemon.go:110] ------------------------------------ I1115 09:41:17.117612 4143292 daemon.go:102] Profile Name: profile1 I1115 09:41:17.117616 4143292 daemon.go:102] Interface: I1115 09:41:17.117620 4143292 daemon.go:102] Ptp4lOpts: -2 I1115 09:41:17.117623 4143292 daemon.go:102] Phc2sysOpts: -a -r -n 24 I1115 09:41:17.117626 4143292 daemon.go:116] ------------------------------------
Additional resources
- For more information about FIFO priority scheduling on PTP hardware, see Configuring FIFO priority scheduling for PTP hardware.
- For more information about configuring PTP fast events, see Configuring the PTP fast event notifications publisher.
17.6.5. Configuring linuxptp services as boundary clocks for dual NIC hardware
You can configure the linuxptp
services (ptp4l
, phc2sys
) as boundary clocks for dual-NIC hardware by creating a PtpConfig
custom resource (CR) object for each NIC.
Dual NIC hardware allows you to connect each NIC to the same upstream leader clock with separate ptp4l
instances for each NIC feeding the downstream clocks.
Prerequisites
-
Install the OpenShift CLI (
oc
). -
Log in as a user with
cluster-admin
privileges. - Install the PTP Operator.
Procedure
Create two separate
PtpConfig
CRs, one for each NIC, using the reference CR in "Configuring linuxptp services as a boundary clock" as the basis for each CR. For example:Create
boundary-clock-ptp-config-nic1.yaml
, specifying values forphc2sysOpts
:apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: boundary-clock-ptp-config-nic1 namespace: openshift-ptp spec: profile: - name: "profile1" ptp4lOpts: "-2 --summary_interval -4" ptp4lConf: | 1 [ens5f1] masterOnly 1 [ens5f0] masterOnly 0 ... phc2sysOpts: "-a -r -m -n 24 -N 8 -R 16" 2
- 1
- Specify the required interfaces to start
ptp4l
as a boundary clock. For example,ens5f0
synchronizes from a grandmaster clock andens5f1
synchronizes connected devices. - 2
- Required
phc2sysOpts
values.-m
prints messages tostdout
. Thelinuxptp-daemon
DaemonSet
parses the logs and generates Prometheus metrics.
Create
boundary-clock-ptp-config-nic2.yaml
, removing thephc2sysOpts
field altogether to disable thephc2sys
service for the second NIC:apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: boundary-clock-ptp-config-nic2 namespace: openshift-ptp spec: profile: - name: "profile2" ptp4lOpts: "-2 --summary_interval -4" ptp4lConf: | 1 [ens7f1] masterOnly 1 [ens7f0] masterOnly 0 ...
- 1
- Specify the required interfaces to start
ptp4l
as a boundary clock on the second NIC.
NoteYou must completely remove the
phc2sysOpts
field from the secondPtpConfig
CR to disable thephc2sys
service on the second NIC.
Create the dual NIC
PtpConfig
CRs by running the following commands:Create the CR that configures PTP for the first NIC:
$ oc create -f boundary-clock-ptp-config-nic1.yaml
Create the CR that configures PTP for the second NIC:
$ oc create -f boundary-clock-ptp-config-nic2.yaml
Verification
Check that the PTP Operator has applied the
PtpConfig
CRs for both NICs. Examine the logs for thelinuxptp
daemon corresponding to the node that has the dual NIC hardware installed. For example, run the following command:$ oc logs linuxptp-daemon-cvgr6 -n openshift-ptp -c linuxptp-daemon-container
Example output
ptp4l[80828.335]: [ptp4l.1.config] master offset 5 s2 freq -5727 path delay 519 ptp4l[80828.343]: [ptp4l.0.config] master offset -5 s2 freq -10607 path delay 533 phc2sys[80828.390]: [ptp4l.0.config] CLOCK_REALTIME phc offset 1 s2 freq -87239 delay 539
17.6.6. Intel Columbiaville E800 series NIC as PTP ordinary clock reference
The following table describes the changes that you must make to the reference PTP configuration in order to use Intel Columbiaville E800 series NICs as ordinary clocks. Make the changes in a PtpConfig
custom resource (CR) that you apply to the cluster.
PTP configuration | Recommended setting |
---|---|
|
|
|
|
|
|
For phc2sysOpts
, -m
prints messages to stdout
. The linuxptp-daemon
DaemonSet
parses the logs and generates Prometheus metrics.
Additional resources
-
For a complete example CR that configures
linuxptp
services as an ordinary clock with PTP fast events, see Configuring linuxptp services as ordinary clock.
17.6.7. Configuring FIFO priority scheduling for PTP hardware
In telco or other deployment configurations that require low latency performance, PTP daemon threads run in a constrained CPU footprint alongside the rest of the infrastructure components. By default, PTP threads run with the SCHED_OTHER
policy. Under high load, these threads might not get the scheduling latency they require for error-free operation.
To mitigate against potential scheduling latency errors, you can configure the PTP Operator linuxptp
services to allow threads to run with a SCHED_FIFO
policy. If SCHED_FIFO
is set for a PtpConfig
CR, then ptp4l
and phc2sys
will run in the parent container under chrt
with a priority set by the ptpSchedulingPriority
field of the PtpConfig
CR.
Setting ptpSchedulingPolicy
is optional, and is only required if you are experiencing latency errors.
Procedure
Edit the
PtpConfig
CR profile:$ oc edit PtpConfig -n openshift-ptp
Change the
ptpSchedulingPolicy
andptpSchedulingPriority
fields:apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: <ptp_config_name> namespace: openshift-ptp ... spec: profile: - name: "profile1" ... ptpSchedulingPolicy: SCHED_FIFO 1 ptpSchedulingPriority: 10 2
-
Save and exit to apply the changes to the
PtpConfig
CR.
Verification
Get the name of the
linuxptp-daemon
pod and corresponding node where thePtpConfig
CR has been applied:$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-gmv2n 3/3 Running 0 1d17h 10.1.196.24 compute-0.example.com linuxptp-daemon-lgm55 3/3 Running 0 1d17h 10.1.196.25 compute-1.example.com ptp-operator-3r4dcvf7f4-zndk7 1/1 Running 0 1d7h 10.129.0.61 control-plane-1.example.com
Check that the
ptp4l
process is running with the updatedchrt
FIFO priority:$ oc -n openshift-ptp logs linuxptp-daemon-lgm55 -c linuxptp-daemon-container|grep chrt
Example output
I1216 19:24:57.091872 1600715 daemon.go:285] /bin/chrt -f 65 /usr/sbin/ptp4l -f /var/run/ptp4l.0.config -2 --summary_interval -4 -m
17.6.8. Configuring log filtering for linuxptp services
The linuxptp
daemon generates logs that you can use for debugging purposes. In telco or other deployment configurations that feature a limited storage capacity, these logs can add to the storage demand.
To reduce the number log messages, you can configure the PtpConfig
custom resource (CR) to exclude log messages that report the master offset
value. The master offset
log message reports the difference between the current node’s clock and the master clock in nanoseconds.
Prerequisites
-
Install the OpenShift CLI (
oc
). -
Log in as a user with
cluster-admin
privileges. - Install the PTP Operator.
Procedure
Edit the
PtpConfig
CR:$ oc edit PtpConfig -n openshift-ptp
In
spec.profile
, add theptpSettings.logReduce
specification and set the value totrue
:apiVersion: ptp.openshift.io/v1 kind: PtpConfig metadata: name: <ptp_config_name> namespace: openshift-ptp ... spec: profile: - name: "profile1" ... ptpSettings: logReduce: "true"
NoteFor debugging purposes, you can revert this specification to
False
to include the master offset messages.-
Save and exit to apply the changes to the
PtpConfig
CR.
Verification
Get the name of the
linuxptp-daemon
pod and corresponding node where thePtpConfig
CR has been applied:$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-gmv2n 3/3 Running 0 1d17h 10.1.196.24 compute-0.example.com linuxptp-daemon-lgm55 3/3 Running 0 1d17h 10.1.196.25 compute-1.example.com ptp-operator-3r4dcvf7f4-zndk7 1/1 Running 0 1d7h 10.129.0.61 control-plane-1.example.com
Verify that master offset messages are excluded from the logs by running the following command:
$ oc -n openshift-ptp logs <linux_daemon_container> -c linuxptp-daemon-container | grep "master offset" 1
- 1
- <linux_daemon_container> is the name of the
linuxptp-daemon
pod, for examplelinuxptp-daemon-gmv2n
.
When you configure the
logReduce
specification, this command does not report any instances ofmaster offset
in the logs of thelinuxptp
daemon.
17.7. Troubleshooting common PTP Operator issues
Troubleshoot common problems with the PTP Operator by performing the following steps.
Prerequisites
-
Install the OpenShift Container Platform CLI (
oc
). -
Log in as a user with
cluster-admin
privileges. - Install the PTP Operator on a bare-metal cluster with hosts that support PTP.
Procedure
Check the Operator and operands are successfully deployed in the cluster for the configured nodes.
$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-lmvgn 3/3 Running 0 4d17h 10.1.196.24 compute-0.example.com linuxptp-daemon-qhfg7 3/3 Running 0 4d17h 10.1.196.25 compute-1.example.com ptp-operator-6b8dcbf7f4-zndk7 1/1 Running 0 5d7h 10.129.0.61 control-plane-1.example.com
NoteWhen the PTP fast event bus is enabled, the number of ready
linuxptp-daemon
pods is3/3
. If the PTP fast event bus is not enabled,2/2
is displayed.Check that supported hardware is found in the cluster.
$ oc -n openshift-ptp get nodeptpdevices.ptp.openshift.io
Example output
NAME AGE control-plane-0.example.com 10d control-plane-1.example.com 10d compute-0.example.com 10d compute-1.example.com 10d compute-2.example.com 10d
Check the available PTP network interfaces for a node:
$ oc -n openshift-ptp get nodeptpdevices.ptp.openshift.io <node_name> -o yaml
where:
- <node_name>
Specifies the node you want to query, for example,
compute-0.example.com
.Example output
apiVersion: ptp.openshift.io/v1 kind: NodePtpDevice metadata: creationTimestamp: "2021-09-14T16:52:33Z" generation: 1 name: compute-0.example.com namespace: openshift-ptp resourceVersion: "177400" uid: 30413db0-4d8d-46da-9bef-737bacd548fd spec: {} status: devices: - name: eno1 - name: eno2 - name: eno3 - name: eno4 - name: enp5s0f0 - name: enp5s0f1
Check that the PTP interface is successfully synchronized to the primary clock by accessing the
linuxptp-daemon
pod for the corresponding node.Get the name of the
linuxptp-daemon
pod and corresponding node you want to troubleshoot by running the following command:$ oc get pods -n openshift-ptp -o wide
Example output
NAME READY STATUS RESTARTS AGE IP NODE linuxptp-daemon-lmvgn 3/3 Running 0 4d17h 10.1.196.24 compute-0.example.com linuxptp-daemon-qhfg7 3/3 Running 0 4d17h 10.1.196.25 compute-1.example.com ptp-operator-6b8dcbf7f4-zndk7 1/1 Running 0 5d7h 10.129.0.61 control-plane-1.example.com
Remote shell into the required
linuxptp-daemon
container:$ oc rsh -n openshift-ptp -c linuxptp-daemon-container <linux_daemon_container>
where:
- <linux_daemon_container>
-
is the container you want to diagnose, for example
linuxptp-daemon-lmvgn
.
In the remote shell connection to the
linuxptp-daemon
container, use the PTP Management Client (pmc
) tool to diagnose the network interface. Run the followingpmc
command to check the sync status of the PTP device, for exampleptp4l
.# pmc -u -f /var/run/ptp4l.0.config -b 0 'GET PORT_DATA_SET'
Example output when the node is successfully synced to the primary clock
sending: GET PORT_DATA_SET 40a6b7.fffe.166ef0-1 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET portIdentity 40a6b7.fffe.166ef0-1 portState SLAVE logMinDelayReqInterval -4 peerMeanPathDelay 0 logAnnounceInterval -3 announceReceiptTimeout 3 logSyncInterval -4 delayMechanism 1 logMinPdelayReqInterval -4 versionNumber 2
17.7.1. Collecting Precision Time Protocol (PTP) Operator data
You can use the oc adm must-gather
CLI command to collect information about your cluster, including features and objects associated with Precision Time Protocol (PTP) Operator.
Prerequisites
-
You have access to the cluster as a user with the
cluster-admin
role. -
You have installed the OpenShift CLI (
oc
). - You have installed the PTP Operator.
Procedure
To collect PTP Operator data with
must-gather
, you must specify the PTP Operatormust-gather
image.$ oc adm must-gather --image=registry.redhat.io/openshift4/ptp-must-gather-rhel8:v4.13
17.8. PTP hardware fast event notifications framework
Cloud native applications such as virtual RAN (vRAN) require access to notifications about hardware timing events that are critical to the functioning of the overall network. PTP clock synchronization errors can negatively affect the performance and reliability of your low-latency application, for example, a vRAN application running in a distributed unit (DU).
17.8.1. About PTP and clock synchronization error events
Loss of PTP synchronization is a critical error for a RAN network. If synchronization is lost on a node, the radio might be shut down and the network Over the Air (OTA) traffic might be shifted to another node in the wireless network. Fast event notifications mitigate against workload errors by allowing cluster nodes to communicate PTP clock sync status to the vRAN application running in the DU.
Event notifications are available to vRAN applications running on the same DU node. A publish-subscribe REST API passes events notifications to the messaging bus. Publish-subscribe messaging, or pub-sub messaging, is an asynchronous service-to-service communication architecture where any message published to a topic is immediately received by all of the subscribers to the topic.
The PTP Operator generates fast event notifications for every PTP-capable network interface. You can access the events by using a cloud-event-proxy
sidecar container over an HTTP or Advanced Message Queuing Protocol (AMQP) message bus.
PTP fast event notifications are available for network interfaces configured to use PTP ordinary clocks or PTP boundary clocks.
HTTP transport is the default transport for PTP and bare-metal events. Use HTTP transport instead of AMQP for PTP and bare-metal events where possible. AMQ Interconnect is EOL from 30 June 2024. Extended life cycle support (ELS) for AMQ Interconnect ends 29 November 2029. For more information see, Red Hat AMQ Interconnect support status.
17.8.2. About the PTP fast event notifications framework
Use the Precision Time Protocol (PTP) fast event notifications framework to subscribe cluster applications to PTP events that the bare-metal cluster node generates.
The fast events notifications framework uses a REST API for communication. The REST API is based on the O-RAN O-Cloud Notification API Specification for Event Consumers 3.0 that is available from O-RAN ALLIANCE Specifications.
The framework consists of a publisher, subscriber, and an AMQ or HTTP messaging protocol to handle communications between the publisher and subscriber applications. Applications run the cloud-event-proxy
container in a sidecar pattern to subscribe to PTP events. The cloud-event-proxy
sidecar container can access the same resources as the primary application container without using any of the resources of the primary application and with no significant latency.
HTTP transport is the default transport for PTP and bare-metal events. Use HTTP transport instead of AMQP for PTP and bare-metal events where possible. AMQ Interconnect is EOL from 30 June 2024. Extended life cycle support (ELS) for AMQ Interconnect ends 29 November 2029. For more information see, Red Hat AMQ Interconnect support status.
Figure 17.1. Overview of PTP fast events
- Event is generated on the cluster host
-
linuxptp-daemon
in the PTP Operator-managed pod runs as a KubernetesDaemonSet
and manages the variouslinuxptp
processes (ptp4l
,phc2sys
, and optionally for grandmaster clocks,ts2phc
). Thelinuxptp-daemon
passes the event to the UNIX domain socket. - Event is passed to the cloud-event-proxy sidecar
-
The PTP plugin reads the event from the UNIX domain socket and passes it to the
cloud-event-proxy
sidecar in the PTP Operator-managed pod.cloud-event-proxy
delivers the event from the Kubernetes infrastructure to Cloud-Native Network Functions (CNFs) with low latency. - Event is persisted
-
The
cloud-event-proxy
sidecar in the PTP Operator-managed pod processes the event and publishes the cloud-native event by using a REST API. - Message is transported
-
The message transporter transports the event to the
cloud-event-proxy
sidecar in the application pod over HTTP or AMQP 1.0 QPID. - Event is available from the REST API
-
The
cloud-event-proxy
sidecar in the Application pod processes the event and makes it available by using the REST API. - Consumer application requests a subscription and receives the subscribed event
-
The consumer application sends an API request to the
cloud-event-proxy
sidecar in the application pod to create a PTP events subscription. Thecloud-event-proxy
sidecar creates an AMQ or HTTP messaging listener protocol for the resource specified in the subscription.
The cloud-event-proxy
sidecar in the application pod receives the event from the PTP Operator-managed pod, unwraps the cloud events object to retrieve the data, and posts the event to the consumer application. The consumer application listens to the address specified in the resource qualifier and receives and processes the PTP event.
17.8.3. Configuring the PTP fast event notifications publisher
To start using PTP fast event notifications for a network interface in your cluster, you must enable the fast event publisher in the PTP Operator PtpOperatorConfig
custom resource (CR) and configure ptpClockThreshold
values in a PtpConfig
CR that you create.
Prerequisites
-
You have installed the OpenShift Container Platform CLI (
oc
). -
You have logged in as a user with
cluster-admin
privileges. - You have installed the PTP Operator.
Procedure
Modify the default PTP Operator config to enable PTP fast events.
Save the following YAML in the
ptp-operatorconfig.yaml
file:apiVersion: ptp.openshift.io/v1 kind: PtpOperatorConfig metadata: name: default namespace: openshift-ptp spec: daemonNodeSelector: node-role.kubernetes.io/worker: "" ptpEventConfig: enableEventPublisher: true 1
- 1
- Set
enableEventPublisher
totrue
to enable PTP fast event notifications.
NoteIn OpenShift Container Platform 4.13 or later, you do not need to set the
spec.ptpEventConfig.transportHost
field in thePtpOperatorConfig
resource when you use HTTP transport for PTP events. SettransportHost
only when you use AMQP transport for PTP events.Update the
PtpOperatorConfig
CR:$ oc apply -f ptp-operatorconfig.yaml
Create a
PtpConfig
custom resource (CR) for the PTP enabled interface, and set the required values forptpClockThreshold
andptp4lOpts
. The following YAML illustrates the required values that you must set in thePtpConfig
CR:spec: profile: - name: "profile1" interface: "enp5s0f0" ptp4lOpts: "-2 -s --summary_interval -4" 1 phc2sysOpts: "-a -r -m -n 24 -N 8 -R 16" 2 ptp4lConf: "" 3 ptpClockThreshold: 4 holdOverTimeout: 5 maxOffsetThreshold: 100 minOffsetThreshold: -100
- 1
- Append
--summary_interval -4
to use PTP fast events. - 2
- Required
phc2sysOpts
values.-m
prints messages tostdout
. Thelinuxptp-daemon
DaemonSet
parses the logs and generates Prometheus metrics. - 3
- Specify a string that contains the configuration to replace the default
/etc/ptp4l.conf
file. To use the default configuration, leave the field empty. - 4
- Optional. If the
ptpClockThreshold
stanza is not present, default values are used for theptpClockThreshold
fields. The stanza shows defaultptpClockThreshold
values. TheptpClockThreshold
values configure how long after the PTP master clock is disconnected before PTP events are triggered.holdOverTimeout
is the time value in seconds before the PTP clock event state changes toFREERUN
when the PTP master clock is disconnected. ThemaxOffsetThreshold
andminOffsetThreshold
settings configure offset values in nanoseconds that compare against the values forCLOCK_REALTIME
(phc2sys
) or master offset (ptp4l
). When theptp4l
orphc2sys
offset value is outside this range, the PTP clock state is set toFREERUN
. When the offset value is within this range, the PTP clock state is set toLOCKED
.
Additional resources
-
For a complete example CR that configures
linuxptp
services as an ordinary clock with PTP fast events, see Configuring linuxptp services as ordinary clock.
17.8.4. Migrating consumer applications to use HTTP transport for PTP or bare-metal events
If you have previously deployed PTP or bare-metal events consumer applications, you need to update the applications to use HTTP message transport.
Prerequisites
-
You have installed the OpenShift CLI (
oc
). -
You have logged in as a user with
cluster-admin
privileges. - You have updated the PTP Operator or Bare Metal Event Relay to version 4.13+ which uses HTTP transport by default.
Procedure
Update your events consumer application to use HTTP transport. Set the
http-event-publishers
variable for the cloud event sidecar deployment.For example, in a cluster with PTP events configured, the following YAML snippet illustrates a cloud event sidecar deployment:
containers: - name: cloud-event-sidecar image: cloud-event-sidecar args: - "--metrics-addr=127.0.0.1:9091" - "--store-path=/store" - "--transport-host=consumer-events-subscription-service.cloud-events.svc.cluster.local:9043" - "--http-event-publishers=ptp-event-publisher-service-NODE_NAME.openshift-ptp.svc.cluster.local:9043" 1 - "--api-port=8089"
- 1
- The PTP Operator automatically resolves
NODE_NAME
to the host that is generating the PTP events. For example,compute-1.example.com
.
In a cluster with bare-metal events configured, set the
http-event-publishers
field tohw-event-publisher-service.openshift-bare-metal-events.svc.cluster.local:9043
in the cloud event sidecar deployment CR.Deploy the
consumer-events-subscription-service
service alongside the events consumer application. For example:apiVersion: v1 kind: Service metadata: annotations: prometheus.io/scrape: "true" service.alpha.openshift.io/serving-cert-secret-name: sidecar-consumer-secret name: consumer-events-subscription-service namespace: cloud-events labels: app: consumer-service spec: ports: - name: sub-port port: 9043 selector: app: consumer clusterIP: None sessionAffinity: None type: ClusterIP
17.8.5. Installing the AMQ messaging bus
To pass PTP fast event notifications between publisher and subscriber on a node, you can install and configure an AMQ messaging bus to run locally on the node. To use AMQ messaging, you must install the AMQ Interconnect Operator.
HTTP transport is the default transport for PTP and bare-metal events. Use HTTP transport instead of AMQP for PTP and bare-metal events where possible. AMQ Interconnect is EOL from 30 June 2024. Extended life cycle support (ELS) for AMQ Interconnect ends 29 November 2029. For more information see, Red Hat AMQ Interconnect support status.
Prerequisites
-
Install the OpenShift Container Platform CLI (
oc
). -
Log in as a user with
cluster-admin
privileges.
Procedure
-
Install the AMQ Interconnect Operator to its own
amq-interconnect
namespace. See Adding the Red Hat Integration - AMQ Interconnect Operator.
Verification
Check that the AMQ Interconnect Operator is available and the required pods are running:
$ oc get pods -n amq-interconnect
Example output
NAME READY STATUS RESTARTS AGE amq-interconnect-645db76c76-k8ghs 1/1 Running 0 23h interconnect-operator-5cb5fc7cc-4v7qm 1/1 Running 0 23h
Check that the required
linuxptp-daemon
PTP event producer pods are running in theopenshift-ptp
namespace.$ oc get pods -n openshift-ptp
Example output
NAME READY STATUS RESTARTS AGE linuxptp-daemon-2t78p 3/3 Running 0 12h linuxptp-daemon-k8n88 3/3 Running 0 12h
17.8.6. Subscribing DU applications to PTP events REST API reference
Use the PTP event notifications REST API to subscribe a distributed unit (DU) application to the PTP events that are generated on the parent node.
Subscribe applications to PTP events by using the resource address /cluster/node/<node_name>/ptp
, where <node_name>
is the cluster node running the DU application.
Deploy your cloud-event-consumer
DU application container and cloud-event-proxy
sidecar container in a separate DU application pod. The cloud-event-consumer
DU application subscribes to the cloud-event-proxy
container in the application pod.
Use the following API endpoints to subscribe the cloud-event-consumer
DU application to PTP events posted by the cloud-event-proxy
container at http://localhost:8089/api/ocloudNotifications/v1/
in the DU application pod:
/api/ocloudNotifications/v1/subscriptions
-
POST
: Creates a new subscription -
GET
: Retrieves a list of subscriptions -
DELETE
: Deletes all subscriptions
-
/api/ocloudNotifications/v1/subscriptions/<subscription_id>
-
GET
: Returns details for the specified subscription ID -
DELETE
: Deletes the subscription associated with the specified subscription ID
-
/api/ocloudNotifications/v1/health
-
GET
: Returns the health status ofocloudNotifications
API
-
api/ocloudNotifications/v1/publishers
-
GET
: Returns an array ofos-clock-sync-state
,ptp-clock-class-change
, andlock-state
messages for the cluster node
-
/api/ocloudnotifications/v1/{resource_address}/CurrentState
-
GET
: Returns the current state of one the following event types:os-clock-sync-state
,ptp-clock-class-change
, orlock-state
events
-
9089
is the default port for the cloud-event-consumer
container deployed in the application pod. You can configure a different port for your DU application as required.
17.8.6.1. api/ocloudNotifications/v1/subscriptions
HTTP method
GET api/ocloudNotifications/v1/subscriptions
Description
Returns a list of subscriptions. If subscriptions exist, a 200 OK
status code is returned along with the list of subscriptions.
Example API response
[ { "id": "75b1ad8f-c807-4c23-acf5-56f4b7ee3826", "endpointUri": "http://localhost:9089/event", "uriLocation": "http://localhost:8089/api/ocloudNotifications/v1/subscriptions/75b1ad8f-c807-4c23-acf5-56f4b7ee3826", "resource": "/cluster/node/compute-1.example.com/ptp" } ]
HTTP method
POST api/ocloudNotifications/v1/subscriptions
Description
Creates a new subscription. If a subscription is successfully created, or if it already exists, a 201 Created
status code is returned.
Parameter | Type |
---|---|
subscription | data |
Example payload
{ "uriLocation": "http://localhost:8089/api/ocloudNotifications/v1/subscriptions", "resource": "/cluster/node/compute-1.example.com/ptp" }
HTTP method
DELETE api/ocloudNotifications/v1/subscriptions
Description
Deletes all subscriptions.
Example API response
{ "status": "deleted all subscriptions" }
17.8.6.2. api/ocloudNotifications/v1/subscriptions/{subscription_id}
HTTP method
GET api/ocloudNotifications/v1/subscriptions/{subscription_id}
Description
Returns details for the subscription with ID subscription_id
.
Parameter | Type |
---|---|
| string |
Example API response
{ "id":"48210fb3-45be-4ce0-aa9b-41a0e58730ab", "endpointUri": "http://localhost:9089/event", "uriLocation":"http://localhost:8089/api/ocloudNotifications/v1/subscriptions/48210fb3-45be-4ce0-aa9b-41a0e58730ab", "resource":"/cluster/node/compute-1.example.com/ptp" }
HTTP method
DELETE api/ocloudNotifications/v1/subscriptions/{subscription_id}
Description
Deletes the subscription with ID subscription_id
.
Parameter | Type |
---|---|
| string |
Example API response
{ "status": "OK" }
17.8.6.3. api/ocloudNotifications/v1/health
HTTP method
GET api/ocloudNotifications/v1/health/
Description
Returns the health status for the ocloudNotifications
REST API.
Example API response
OK
17.8.6.4. api/ocloudNotifications/v1/publishers
HTTP method
GET api/ocloudNotifications/v1/publishers
Description
Returns an array of os-clock-sync-state
, ptp-clock-class-change
, and lock-state
details for the cluster node. The system generates notifications when the relevant equipment state changes.
-
os-clock-sync-state
notifications describe the host operating system clock synchronization state. Can be inLOCKED
orFREERUN
state. -
ptp-clock-class-change
notifications describe the current state of the PTP clock class. -
lock-state
notifications describe the current status of the PTP equipment lock state. Can be inLOCKED
,HOLDOVER
orFREERUN
state.
Example API response
[ { "id": "0fa415ae-a3cf-4299-876a-589438bacf75", "endpointUri": "http://localhost:9085/api/ocloudNotifications/v1/dummy", "uriLocation": "http://localhost:9085/api/ocloudNotifications/v1/publishers/0fa415ae-a3cf-4299-876a-589438bacf75", "resource": "/cluster/node/compute-1.example.com/sync/sync-status/os-clock-sync-state" }, { "id": "28cd82df-8436-4f50-bbd9-7a9742828a71", "endpointUri": "http://localhost:9085/api/ocloudNotifications/v1/dummy", "uriLocation": "http://localhost:9085/api/ocloudNotifications/v1/publishers/28cd82df-8436-4f50-bbd9-7a9742828a71", "resource": "/cluster/node/compute-1.example.com/sync/ptp-status/ptp-clock-class-change" }, { "id": "44aa480d-7347-48b0-a5b0-e0af01fa9677", "endpointUri": "http://localhost:9085/api/ocloudNotifications/v1/dummy", "uriLocation": "http://localhost:9085/api/ocloudNotifications/v1/publishers/44aa480d-7347-48b0-a5b0-e0af01fa9677", "resource": "/cluster/node/compute-1.example.com/sync/ptp-status/lock-state" } ]
You can find os-clock-sync-state
, ptp-clock-class-change
and lock-state
events in the logs for the cloud-event-proxy
container. For example:
$ oc logs -f linuxptp-daemon-cvgr6 -n openshift-ptp -c cloud-event-proxy
Example os-clock-sync-state event
{ "id":"c8a784d1-5f4a-4c16-9a81-a3b4313affe5", "type":"event.sync.sync-status.os-clock-sync-state-change", "source":"/cluster/compute-1.example.com/ptp/CLOCK_REALTIME", "dataContentType":"application/json", "time":"2022-05-06T15:31:23.906277159Z", "data":{ "version":"v1", "values":[ { "resource":"/sync/sync-status/os-clock-sync-state", "dataType":"notification", "valueType":"enumeration", "value":"LOCKED" }, { "resource":"/sync/sync-status/os-clock-sync-state", "dataType":"metric", "valueType":"decimal64.3", "value":"-53" } ] } }
Example ptp-clock-class-change event
{ "id":"69eddb52-1650-4e56-b325-86d44688d02b", "type":"event.sync.ptp-status.ptp-clock-class-change", "source":"/cluster/compute-1.example.com/ptp/ens2fx/master", "dataContentType":"application/json", "time":"2022-05-06T15:31:23.147100033Z", "data":{ "version":"v1", "values":[ { "resource":"/sync/ptp-status/ptp-clock-class-change", "dataType":"metric", "valueType":"decimal64.3", "value":"135" } ] } }
Example lock-state event
{ "id":"305ec18b-1472-47b3-aadd-8f37933249a9", "type":"event.sync.ptp-status.ptp-state-change", "source":"/cluster/compute-1.example.com/ptp/ens2fx/master", "dataContentType":"application/json", "time":"2022-05-06T15:31:23.467684081Z", "data":{ "version":"v1", "values":[ { "resource":"/sync/ptp-status/lock-state", "dataType":"notification", "valueType":"enumeration", "value":"LOCKED" }, { "resource":"/sync/ptp-status/lock-state", "dataType":"metric", "valueType":"decimal64.3", "value":"62" } ] } }
17.8.6.5. api/ocloudNotifications/v1/{resource_address}/CurrentState
HTTP method
GET api/ocloudNotifications/v1/cluster/node/<node_name>/sync/ptp-status/lock-state/CurrentState
GET api/ocloudNotifications/v1/cluster/node/<node_name>/sync/sync-status/os-clock-sync-state/CurrentState
GET api/ocloudNotifications/v1/cluster/node/<node_name>/sync/ptp-status/ptp-clock-class-change/CurrentState
Description
Configure the CurrentState
API endpoint to return the current state of the os-clock-sync-state
, ptp-clock-class-change
, or lock-state
events for the cluster node.
-
os-clock-sync-state
notifications describe the host operating system clock synchronization state. Can be inLOCKED
orFREERUN
state. -
ptp-clock-class-change
notifications describe the current state of the PTP clock class. -
lock-state
notifications describe the current status of the PTP equipment lock state. Can be inLOCKED
,HOLDOVER
orFREERUN
state.
Parameter | Type |
---|---|
| string |
Example lock-state API response
{ "id": "c1ac3aa5-1195-4786-84f8-da0ea4462921", "type": "event.sync.ptp-status.ptp-state-change", "source": "/cluster/node/compute-1.example.com/sync/ptp-status/lock-state", "dataContentType": "application/json", "time": "2023-01-10T02:41:57.094981478Z", "data": { "version": "v1", "values": [ { "resource": "/cluster/node/compute-1.example.com/ens5fx/master", "dataType": "notification", "valueType": "enumeration", "value": "LOCKED" }, { "resource": "/cluster/node/compute-1.example.com/ens5fx/master", "dataType": "metric", "valueType": "decimal64.3", "value": "29" } ] } }
Example os-clock-sync-state API response
{ "specversion": "0.3", "id": "4f51fe99-feaa-4e66-9112-66c5c9b9afcb", "source": "/cluster/node/compute-1.example.com/sync/sync-status/os-clock-sync-state", "type": "event.sync.sync-status.os-clock-sync-state-change", "subject": "/cluster/node/compute-1.example.com/sync/sync-status/os-clock-sync-state", "datacontenttype": "application/json", "time": "2022-11-29T17:44:22.202Z", "data": { "version": "v1", "values": [ { "resource": "/cluster/node/compute-1.example.com/CLOCK_REALTIME", "dataType": "notification", "valueType": "enumeration", "value": "LOCKED" }, { "resource": "/cluster/node/compute-1.example.com/CLOCK_REALTIME", "dataType": "metric", "valueType": "decimal64.3", "value": "27" } ] } }
Example ptp-clock-class-change API response
{ "id": "064c9e67-5ad4-4afb-98ff-189c6aa9c205", "type": "event.sync.ptp-status.ptp-clock-class-change", "source": "/cluster/node/compute-1.example.com/sync/ptp-status/ptp-clock-class-change", "dataContentType": "application/json", "time": "2023-01-10T02:41:56.785673989Z", "data": { "version": "v1", "values": [ { "resource": "/cluster/node/compute-1.example.com/ens5fx/master", "dataType": "metric", "valueType": "decimal64.3", "value": "165" } ] } }
17.8.7. Monitoring PTP fast event metrics
You can monitor PTP fast events metrics from cluster nodes where the linuxptp-daemon
is running. You can also monitor PTP fast event metrics in the OpenShift Container Platform web console by using the preconfigured and self-updating Prometheus monitoring stack.
Prerequisites
-
Install the OpenShift Container Platform CLI
oc
. -
Log in as a user with
cluster-admin
privileges. - Install and configure the PTP Operator on a node with PTP-capable hardware.
Procedure
Check for exposed PTP metrics on any node where the
linuxptp-daemon
is running. For example, run the following command:$ curl http://<node_name>:9091/metrics
Example output
# HELP openshift_ptp_clock_state 0 = FREERUN, 1 = LOCKED, 2 = HOLDOVER # TYPE openshift_ptp_clock_state gauge openshift_ptp_clock_state{iface="ens1fx",node="compute-1.example.com",process="ptp4l"} 1 openshift_ptp_clock_state{iface="ens3fx",node="compute-1.example.com",process="ptp4l"} 1 openshift_ptp_clock_state{iface="ens5fx",node="compute-1.example.com",process="ptp4l"} 1 openshift_ptp_clock_state{iface="ens7fx",node="compute-1.example.com",process="ptp4l"} 1 # HELP openshift_ptp_delay_ns # TYPE openshift_ptp_delay_ns gauge openshift_ptp_delay_ns{from="master",iface="ens1fx",node="compute-1.example.com",process="ptp4l"} 842 openshift_ptp_delay_ns{from="master",iface="ens3fx",node="compute-1.example.com",process="ptp4l"} 480 openshift_ptp_delay_ns{from="master",iface="ens5fx",node="compute-1.example.com",process="ptp4l"} 584 openshift_ptp_delay_ns{from="master",iface="ens7fx",node="compute-1.example.com",process="ptp4l"} 482 openshift_ptp_delay_ns{from="phc",iface="CLOCK_REALTIME",node="compute-1.example.com",process="phc2sys"} 547 # HELP openshift_ptp_offset_ns # TYPE openshift_ptp_offset_ns gauge openshift_ptp_offset_ns{from="master",iface="ens1fx",node="compute-1.example.com",process="ptp4l"} -2 openshift_ptp_offset_ns{from="master",iface="ens3fx",node="compute-1.example.com",process="ptp4l"} -44 openshift_ptp_offset_ns{from="master",iface="ens5fx",node="compute-1.example.com",process="ptp4l"} -8 openshift_ptp_offset_ns{from="master",iface="ens7fx",node="compute-1.example.com",process="ptp4l"} 3 openshift_ptp_offset_ns{from="phc",iface="CLOCK_REALTIME",node="compute-1.example.com",process="phc2sys"} 12
-
To view the PTP event in the OpenShift Container Platform web console, copy the name of the PTP metric you want to query, for example,
openshift_ptp_offset_ns
. -
In the OpenShift Container Platform web console, click Observe
Metrics. - Paste the PTP metric name into the Expression field, and click Run queries.
Additional resources