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Chapter 7. Validating single-node OpenShift cluster tuning for vDU application workloads

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Before you can deploy virtual distributed unit (vDU) applications, you need to tune and configure the cluster host firmware and various other cluster configuration settings. Use the following information to validate the cluster configuration to support vDU workloads.

7.1. Recommended firmware configuration for vDU cluster hosts

Use the following table as the basis to configure the cluster host firmware for vDU applications running on OpenShift Container Platform 4.16.

Note

The following table is a general recommendation for vDU cluster host firmware configuration. Exact firmware settings will depend on your requirements and specific hardware platform. Automatic setting of firmware is not handled by the zero touch provisioning pipeline.

Table 7.1. Recommended cluster host firmware settings
Firmware settingConfigurationDescription

HyperTransport (HT)

Enabled

HyperTransport (HT) bus is a bus technology developed by AMD. HT provides a high-speed link between the components in the host memory and other system peripherals.

UEFI

Enabled

Enable booting from UEFI for the vDU host.

CPU Power and Performance Policy

Performance

Set CPU Power and Performance Policy to optimize the system for performance over energy efficiency.

Uncore Frequency Scaling

Disabled

Disable Uncore Frequency Scaling to prevent the voltage and frequency of non-core parts of the CPU from being set independently.

Uncore Frequency

Maximum

Sets the non-core parts of the CPU such as cache and memory controller to their maximum possible frequency of operation.

Performance P-limit

Disabled

Disable Performance P-limit to prevent the Uncore frequency coordination of processors.

Enhanced Intel® SpeedStep Tech

Enabled

Enable Enhanced Intel SpeedStep to allow the system to dynamically adjust processor voltage and core frequency that decreases power consumption and heat production in the host.

Intel® Turbo Boost Technology

Enabled

Enable Turbo Boost Technology for Intel-based CPUs to automatically allow processor cores to run faster than the rated operating frequency if they are operating below power, current, and temperature specification limits.

Intel Configurable TDP

Enabled

Enables Thermal Design Power (TDP) for the CPU.

Configurable TDP Level

Level 2

TDP level sets the CPU power consumption required for a particular performance rating. TDP level 2 sets the CPU to the most stable performance level at the cost of power consumption.

Energy Efficient Turbo

Disabled

Disable Energy Efficient Turbo to prevent the processor from using an energy-efficiency based policy.

Hardware P-States

Enabled or Disabled

Enable OS-controlled P-States to allow power saving configurations. Disable P-states (performance states) to optimize the operating system and CPU for performance over power consumption.

Package C-State

C0/C1 state

Use C0 or C1 states to set the processor to a fully active state (C0) or to stop CPU internal clocks running in software (C1).

C1E

Disabled

CPU Enhanced Halt (C1E) is a power saving feature in Intel chips. Disabling C1E prevents the operating system from sending a halt command to the CPU when inactive.

Processor C6

Disabled

C6 power-saving is a CPU feature that automatically disables idle CPU cores and cache. Disabling C6 improves system performance.

Sub-NUMA Clustering

Disabled

Sub-NUMA clustering divides the processor cores, cache, and memory into multiple NUMA domains. Disabling this option can increase performance for latency-sensitive workloads.

Note

Enable global SR-IOV and VT-d settings in the firmware for the host. These settings are relevant to bare-metal environments.

Note

Enable both C-states and OS-controlled P-States to allow per pod power management.

7.2. Recommended cluster configurations to run vDU applications

Clusters running virtualized distributed unit (vDU) applications require a highly tuned and optimized configuration. The following information describes the various elements that you require to support vDU workloads in OpenShift Container Platform 4.16 clusters.

7.2.4. Checking the realtime kernel version

Always use the latest version of the realtime kernel in your OpenShift Container Platform clusters. If you are unsure about the kernel version that is in use in the cluster, you can compare the current realtime kernel version to the release version with the following procedure.

Prerequisites

  • You have installed the OpenShift CLI (oc).
  • You are logged in as a user with cluster-admin privileges.
  • You have installed podman.

Procedure

  1. Run the following command to get the cluster version:

    $ OCP_VERSION=$(oc get clusterversion version -o jsonpath='{.status.desired.version}{"\n"}')
  2. Get the release image SHA number:

    $ DTK_IMAGE=$(oc adm release info --image-for=driver-toolkit quay.io/openshift-release-dev/ocp-release:$OCP_VERSION-x86_64)
  3. Run the release image container and extract the kernel version that is packaged with cluster’s current release:

    $ podman run --rm $DTK_IMAGE rpm -qa | grep 'kernel-rt-core-' | sed 's#kernel-rt-core-##'

    Example output

    4.18.0-305.49.1.rt7.121.el8_4.x86_64

    This is the default realtime kernel version that ships with the release.

    Note

    The realtime kernel is denoted by the string .rt in the kernel version.

Verification

Check that the kernel version listed for the cluster’s current release matches actual realtime kernel that is running in the cluster. Run the following commands to check the running realtime kernel version:

  1. Open a remote shell connection to the cluster node:

    $ oc debug node/<node_name>
  2. Check the realtime kernel version:

    sh-4.4# uname -r

    Example output

    4.18.0-305.49.1.rt7.121.el8_4.x86_64

7.3. Checking that the recommended cluster configurations are applied

You can check that clusters are running the correct configuration. The following procedure describes how to check the various configurations that you require to deploy a DU application in OpenShift Container Platform 4.16 clusters.

Prerequisites

  • You have deployed a cluster and tuned it for vDU workloads.
  • You have installed the OpenShift CLI (oc).
  • You have logged in as a user with cluster-admin privileges.

Procedure

  1. Check that the default OperatorHub sources are disabled. Run the following command:

    $ oc get operatorhub cluster -o yaml

    Example output

    spec:
        disableAllDefaultSources: true

  2. Check that all required CatalogSource resources are annotated for workload partitioning (PreferredDuringScheduling) by running the following command:

    $ oc get catalogsource -A -o jsonpath='{range .items[*]}{.metadata.name}{" -- "}{.metadata.annotations.target\.workload\.openshift\.io/management}{"\n"}{end}'

    Example output

    certified-operators -- {"effect": "PreferredDuringScheduling"}
    community-operators -- {"effect": "PreferredDuringScheduling"}
    ran-operators 1
    redhat-marketplace -- {"effect": "PreferredDuringScheduling"}
    redhat-operators -- {"effect": "PreferredDuringScheduling"}

    1
    CatalogSource resources that are not annotated are also returned. In this example, the ran-operators CatalogSource resource is not annotated and does not have the PreferredDuringScheduling annotation.
    Note

    In a properly configured vDU cluster, only a single annotated catalog source is listed.

  3. Check that all applicable OpenShift Container Platform Operator namespaces are annotated for workload partitioning. This includes all Operators installed with core OpenShift Container Platform and the set of additional Operators included in the reference DU tuning configuration. Run the following command:

    $ oc get namespaces -A -o jsonpath='{range .items[*]}{.metadata.name}{" -- "}{.metadata.annotations.workload\.openshift\.io/allowed}{"\n"}{end}'

    Example output

    default --
    openshift-apiserver -- management
    openshift-apiserver-operator -- management
    openshift-authentication -- management
    openshift-authentication-operator -- management

    Important

    Additional Operators must not be annotated for workload partitioning. In the output from the previous command, additional Operators should be listed without any value on the right side of the -- separator.

  4. Check that the ClusterLogging configuration is correct. Run the following commands:

    1. Validate that the appropriate input and output logs are configured:

      $ oc get -n openshift-logging ClusterLogForwarder instance -o yaml

      Example output

      apiVersion: logging.openshift.io/v1
      kind: ClusterLogForwarder
      metadata:
        creationTimestamp: "2022-07-19T21:51:41Z"
        generation: 1
        name: instance
        namespace: openshift-logging
        resourceVersion: "1030342"
        uid: 8c1a842d-80c5-447a-9150-40350bdf40f0
      spec:
        inputs:
        - infrastructure: {}
          name: infra-logs
        outputs:
        - name: kafka-open
          type: kafka
          url: tcp://10.46.55.190:9092/test
        pipelines:
        - inputRefs:
          - audit
          name: audit-logs
          outputRefs:
          - kafka-open
        - inputRefs:
          - infrastructure
          name: infrastructure-logs
          outputRefs:
          - kafka-open
      ...

    2. Check that the curation schedule is appropriate for your application:

      $ oc get -n openshift-logging clusterloggings.logging.openshift.io instance -o yaml

      Example output

      apiVersion: logging.openshift.io/v1
      kind: ClusterLogging
      metadata:
        creationTimestamp: "2022-07-07T18:22:56Z"
        generation: 1
        name: instance
        namespace: openshift-logging
        resourceVersion: "235796"
        uid: ef67b9b8-0e65-4a10-88ff-ec06922ea796
      spec:
        collection:
          logs:
            fluentd: {}
            type: fluentd
        curation:
          curator:
            schedule: 30 3 * * *
          type: curator
        managementState: Managed
      ...

  5. Check that the web console is disabled (managementState: Removed) by running the following command:

    $ oc get consoles.operator.openshift.io cluster -o jsonpath="{ .spec.managementState }"

    Example output

    Removed

  6. Check that chronyd is disabled on the cluster node by running the following commands:

    $ oc debug node/<node_name>

    Check the status of chronyd on the node:

    sh-4.4# chroot /host
    sh-4.4# systemctl status chronyd

    Example output

    ● chronyd.service - NTP client/server
        Loaded: loaded (/usr/lib/systemd/system/chronyd.service; disabled; vendor preset: enabled)
        Active: inactive (dead)
          Docs: man:chronyd(8)
                man:chrony.conf(5)

  7. Check that the PTP interface is successfully synchronized to the primary clock using a remote shell connection to the linuxptp-daemon container and the PTP Management Client (pmc) tool:

    1. Set the $PTP_POD_NAME variable with the name of the linuxptp-daemon pod by running the following command:

      $ PTP_POD_NAME=$(oc get pods -n openshift-ptp -l app=linuxptp-daemon -o name)
    2. Run the following command to check the sync status of the PTP device:

      $ oc -n openshift-ptp rsh -c linuxptp-daemon-container ${PTP_POD_NAME} pmc -u -f /var/run/ptp4l.0.config -b 0 'GET PORT_DATA_SET'

      Example output

      sending: GET PORT_DATA_SET
        3cecef.fffe.7a7020-1 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
          portIdentity            3cecef.fffe.7a7020-1
          portState               SLAVE
          logMinDelayReqInterval  -4
          peerMeanPathDelay       0
          logAnnounceInterval     1
          announceReceiptTimeout  3
          logSyncInterval         0
          delayMechanism          1
          logMinPdelayReqInterval 0
          versionNumber           2
        3cecef.fffe.7a7020-2 seq 0 RESPONSE MANAGEMENT PORT_DATA_SET
          portIdentity            3cecef.fffe.7a7020-2
          portState               LISTENING
          logMinDelayReqInterval  0
          peerMeanPathDelay       0
          logAnnounceInterval     1
          announceReceiptTimeout  3
          logSyncInterval         0
          delayMechanism          1
          logMinPdelayReqInterval 0
          versionNumber           2

    3. Run the following pmc command to check the PTP clock status:

      $ oc -n openshift-ptp rsh -c linuxptp-daemon-container ${PTP_POD_NAME} pmc -u -f /var/run/ptp4l.0.config -b 0 'GET TIME_STATUS_NP'

      Example output

      sending: GET TIME_STATUS_NP
        3cecef.fffe.7a7020-0 seq 0 RESPONSE MANAGEMENT TIME_STATUS_NP
          master_offset              10 1
          ingress_time               1657275432697400530
          cumulativeScaledRateOffset +0.000000000
          scaledLastGmPhaseChange    0
          gmTimeBaseIndicator        0
          lastGmPhaseChange          0x0000'0000000000000000.0000
          gmPresent                  true 2
          gmIdentity                 3c2c30.ffff.670e00

      1
      master_offset should be between -100 and 100 ns.
      2
      Indicates that the PTP clock is synchronized to a master, and the local clock is not the grandmaster clock.
    4. Check that the expected master offset value corresponding to the value in /var/run/ptp4l.0.config is found in the linuxptp-daemon-container log:

      $ oc logs $PTP_POD_NAME -n openshift-ptp -c linuxptp-daemon-container

      Example output

      phc2sys[56020.341]: [ptp4l.1.config] CLOCK_REALTIME phc offset  -1731092 s2 freq -1546242 delay    497
      ptp4l[56020.390]: [ptp4l.1.config] master offset         -2 s2 freq   -5863 path delay       541
      ptp4l[56020.390]: [ptp4l.0.config] master offset         -8 s2 freq  -10699 path delay       533

  8. Check that the SR-IOV configuration is correct by running the following commands:

    1. Check that the disableDrain value in the SriovOperatorConfig resource is set to true:

      $ oc get sriovoperatorconfig -n openshift-sriov-network-operator default -o jsonpath="{.spec.disableDrain}{'\n'}"

      Example output

      true

    2. Check that the SriovNetworkNodeState sync status is Succeeded by running the following command:

      $ oc get SriovNetworkNodeStates -n openshift-sriov-network-operator -o jsonpath="{.items[*].status.syncStatus}{'\n'}"

      Example output

      Succeeded

    3. Verify that the expected number and configuration of virtual functions (Vfs) under each interface configured for SR-IOV is present and correct in the .status.interfaces field. For example:

      $ oc get SriovNetworkNodeStates -n openshift-sriov-network-operator -o yaml

      Example output

      apiVersion: v1
      items:
      - apiVersion: sriovnetwork.openshift.io/v1
        kind: SriovNetworkNodeState
      ...
        status:
          interfaces:
          ...
          - Vfs:
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.0
              vendor: "8086"
              vfID: 0
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.1
              vendor: "8086"
              vfID: 1
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.2
              vendor: "8086"
              vfID: 2
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.3
              vendor: "8086"
              vfID: 3
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.4
              vendor: "8086"
              vfID: 4
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.5
              vendor: "8086"
              vfID: 5
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.6
              vendor: "8086"
              vfID: 6
            - deviceID: 154c
              driver: vfio-pci
              pciAddress: 0000:3b:0a.7
              vendor: "8086"
              vfID: 7

  9. Check that the cluster performance profile is correct. The cpu and hugepages sections will vary depending on your hardware configuration. Run the following command:

    $ oc get PerformanceProfile openshift-node-performance-profile -o yaml

    Example output

    apiVersion: performance.openshift.io/v2
    kind: PerformanceProfile
    metadata:
      creationTimestamp: "2022-07-19T21:51:31Z"
      finalizers:
      - foreground-deletion
      generation: 1
      name: openshift-node-performance-profile
      resourceVersion: "33558"
      uid: 217958c0-9122-4c62-9d4d-fdc27c31118c
    spec:
      additionalKernelArgs:
      - idle=poll
      - rcupdate.rcu_normal_after_boot=0
      - efi=runtime
      cpu:
        isolated: 2-51,54-103
        reserved: 0-1,52-53
      hugepages:
        defaultHugepagesSize: 1G
        pages:
        - count: 32
          size: 1G
      machineConfigPoolSelector:
        pools.operator.machineconfiguration.openshift.io/master: ""
      net:
        userLevelNetworking: true
      nodeSelector:
        node-role.kubernetes.io/master: ""
      numa:
        topologyPolicy: restricted
      realTimeKernel:
        enabled: true
    status:
      conditions:
      - lastHeartbeatTime: "2022-07-19T21:51:31Z"
        lastTransitionTime: "2022-07-19T21:51:31Z"
        status: "True"
        type: Available
      - lastHeartbeatTime: "2022-07-19T21:51:31Z"
        lastTransitionTime: "2022-07-19T21:51:31Z"
        status: "True"
        type: Upgradeable
      - lastHeartbeatTime: "2022-07-19T21:51:31Z"
        lastTransitionTime: "2022-07-19T21:51:31Z"
        status: "False"
        type: Progressing
      - lastHeartbeatTime: "2022-07-19T21:51:31Z"
        lastTransitionTime: "2022-07-19T21:51:31Z"
        status: "False"
        type: Degraded
      runtimeClass: performance-openshift-node-performance-profile
      tuned: openshift-cluster-node-tuning-operator/openshift-node-performance-openshift-node-performance-profile

    Note

    CPU settings are dependent on the number of cores available on the server and should align with workload partitioning settings. hugepages configuration is server and application dependent.

  10. Check that the PerformanceProfile was successfully applied to the cluster by running the following command:

    $ oc get performanceprofile openshift-node-performance-profile -o jsonpath="{range .status.conditions[*]}{ @.type }{' -- '}{@.status}{'\n'}{end}"

    Example output

    Available -- True
    Upgradeable -- True
    Progressing -- False
    Degraded -- False

  11. Check the Tuned performance patch settings by running the following command:

    $ oc get tuneds.tuned.openshift.io -n openshift-cluster-node-tuning-operator performance-patch -o yaml

    Example output

    apiVersion: tuned.openshift.io/v1
    kind: Tuned
    metadata:
      creationTimestamp: "2022-07-18T10:33:52Z"
      generation: 1
      name: performance-patch
      namespace: openshift-cluster-node-tuning-operator
      resourceVersion: "34024"
      uid: f9799811-f744-4179-bf00-32d4436c08fd
    spec:
      profile:
      - data: |
          [main]
          summary=Configuration changes profile inherited from performance created tuned
          include=openshift-node-performance-openshift-node-performance-profile
          [bootloader]
          cmdline_crash=nohz_full=2-23,26-47 1
          [sysctl]
          kernel.timer_migration=1
          [scheduler]
          group.ice-ptp=0:f:10:*:ice-ptp.*
          [service]
          service.stalld=start,enable
          service.chronyd=stop,disable
        name: performance-patch
      recommend:
      - machineConfigLabels:
          machineconfiguration.openshift.io/role: master
        priority: 19
        profile: performance-patch

    1
    The cpu list in cmdline=nohz_full= will vary based on your hardware configuration.
  12. Check that cluster networking diagnostics are disabled by running the following command:

    $ oc get networks.operator.openshift.io cluster -o jsonpath='{.spec.disableNetworkDiagnostics}'

    Example output

    true

  13. Check that the Kubelet housekeeping interval is tuned to slower rate. This is set in the containerMountNS machine config. Run the following command:

    $ oc describe machineconfig container-mount-namespace-and-kubelet-conf-master | grep OPENSHIFT_MAX_HOUSEKEEPING_INTERVAL_DURATION

    Example output

    Environment="OPENSHIFT_MAX_HOUSEKEEPING_INTERVAL_DURATION=60s"

  14. Check that Grafana and alertManagerMain are disabled and that the Prometheus retention period is set to 24h by running the following command:

    $ oc get configmap cluster-monitoring-config -n openshift-monitoring -o jsonpath="{ .data.config\.yaml }"

    Example output

    grafana:
      enabled: false
    alertmanagerMain:
      enabled: false
    prometheusK8s:
       retention: 24h

    1. Use the following commands to verify that Grafana and alertManagerMain routes are not found in the cluster:

      $ oc get route -n openshift-monitoring alertmanager-main
      $ oc get route -n openshift-monitoring grafana

      Both queries should return Error from server (NotFound) messages.

  15. Check that there is a minimum of 4 CPUs allocated as reserved for each of the PerformanceProfile, Tuned performance-patch, workload partitioning, and kernel command line arguments by running the following command:

    $ oc get performanceprofile -o jsonpath="{ .items[0].spec.cpu.reserved }"

    Example output

    0-3

    Note

    Depending on your workload requirements, you might require additional reserved CPUs to be allocated.

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