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Chapter 16. Using the Node Observability Operator
The Node Observability Operator collects and stores CRI-O and Kubelet profiling or metrics from scripts of compute nodes.
With the Node Observability Operator, you can query the profiling data, enabling analysis of performance trends in CRI-O and Kubelet. It supports debugging performance-related issues and executing embedded scripts for network metrics by using the run
field in the custom resource definition. To enable CRI-O and Kubelet profiling or scripting, you can configure the type
field in the custom resource definition.
The Node Observability Operator is a Technology Preview feature only. Technology Preview features are not supported with Red Hat production service level agreements (SLAs) and might not be functionally complete. Red Hat does not recommend using them in production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process.
For more information about the support scope of Red Hat Technology Preview features, see Technology Preview Features Support Scope.
16.1. Workflow of the Node Observability Operator
The following workflow outlines on how to query the profiling data using the Node Observability Operator:
- Install the Node Observability Operator in the OpenShift Container Platform cluster.
- Create a NodeObservability custom resource to enable the CRI-O profiling on the worker nodes of your choice.
- Run the profiling query to generate the profiling data.
16.2. Installing the Node Observability Operator
The Node Observability Operator is not installed in OpenShift Container Platform by default. You can install the Node Observability Operator by using the OpenShift Container Platform CLI or the web console.
16.2.1. Installing the Node Observability Operator using the CLI
You can install the Node Observability Operator by using the OpenShift CLI (oc).
Prerequisites
- You have installed the OpenShift CLI (oc).
-
You have access to the cluster with
cluster-admin
privileges.
Procedure
Confirm that the Node Observability Operator is available by running the following command:
$ oc get packagemanifests -n openshift-marketplace node-observability-operator
Example output
NAME CATALOG AGE node-observability-operator Red Hat Operators 9h
Create the
node-observability-operator
namespace by running the following command:$ oc new-project node-observability-operator
Create an
OperatorGroup
object YAML file:cat <<EOF | oc apply -f - apiVersion: operators.coreos.com/v1 kind: OperatorGroup metadata: name: node-observability-operator namespace: node-observability-operator spec: targetNamespaces: [] EOF
Create a
Subscription
object YAML file to subscribe a namespace to an Operator:cat <<EOF | oc apply -f - apiVersion: operators.coreos.com/v1alpha1 kind: Subscription metadata: name: node-observability-operator namespace: node-observability-operator spec: channel: alpha name: node-observability-operator source: redhat-operators sourceNamespace: openshift-marketplace EOF
Verification
View the install plan name by running the following command:
$ oc -n node-observability-operator get sub node-observability-operator -o yaml | yq '.status.installplan.name'
Example output
install-dt54w
Verify the install plan status by running the following command:
$ oc -n node-observability-operator get ip <install_plan_name> -o yaml | yq '.status.phase'
<install_plan_name>
is the install plan name that you obtained from the output of the previous command.Example output
COMPLETE
Verify that the Node Observability Operator is up and running:
$ oc get deploy -n node-observability-operator
Example output
NAME READY UP-TO-DATE AVAILABLE AGE node-observability-operator-controller-manager 1/1 1 1 40h
16.2.2. Installing the Node Observability Operator using the web console
You can install the Node Observability Operator from the OpenShift Container Platform web console.
Prerequisites
-
You have access to the cluster with
cluster-admin
privileges. - You have access to the OpenShift Container Platform web console.
Procedure
- Log in to the OpenShift Container Platform web console.
-
In the Administrator’s navigation panel, expand Operators
OperatorHub. - In the All items field, enter Node Observability Operator and select the Node Observability Operator tile.
- Click Install.
On the Install Operator page, configure the following settings:
- In the Update channel area, click alpha.
- In the Installation mode area, click A specific namespace on the cluster.
- From the Installed Namespace list, select node-observability-operator from the list.
- In the Update approval area, select Automatic.
- Click Install.
Verification
-
In the Administrator’s navigation panel, expand Operators
Installed Operators. - Verify that the Node Observability Operator is listed in the Operators list.
16.3. Requesting CRI-O and Kubelet profiling data using the Node Observability Operator
Creating a Node Observability custom resource to collect CRI-O and Kubelet profiling data.
16.3.1. Creating the Node Observability custom resource
You must create and run the NodeObservability
custom resource (CR) before you run the profiling query. When you run the NodeObservability
CR, it creates the necessary machine config and machine config pool CRs to enable the CRI-O profiling on the worker nodes matching the nodeSelector
.
If CRI-O profiling is not enabled on the worker nodes, the NodeObservabilityMachineConfig
resource gets created. Worker nodes matching the nodeSelector
specified in NodeObservability
CR restarts. This might take 10 or more minutes to complete.
Kubelet profiling is enabled by default.
The CRI-O unix socket of the node is mounted on the agent pod, which allows the agent to communicate with CRI-O to run the pprof request. Similarly, the kubelet-serving-ca
certificate chain is mounted on the agent pod, which allows secure communication between the agent and node’s kubelet endpoint.
Prerequisites
- You have installed the Node Observability Operator.
- You have installed the OpenShift CLI (oc).
-
You have access to the cluster with
cluster-admin
privileges.
Procedure
Log in to the OpenShift Container Platform CLI by running the following command:
$ oc login -u kubeadmin https://<HOSTNAME>:6443
Switch back to the
node-observability-operator
namespace by running the following command:$ oc project node-observability-operator
Create a CR file named
nodeobservability.yaml
that contains the following text:apiVersion: nodeobservability.olm.openshift.io/v1alpha2 kind: NodeObservability metadata: name: cluster 1 spec: nodeSelector: kubernetes.io/hostname: <node_hostname> 2 type: crio-kubelet
Run the
NodeObservability
CR:oc apply -f nodeobservability.yaml
Example output
nodeobservability.olm.openshift.io/cluster created
Review the status of the
NodeObservability
CR by running the following command:$ oc get nob/cluster -o yaml | yq '.status.conditions'
Example output
conditions: conditions: - lastTransitionTime: "2022-07-05T07:33:54Z" message: 'DaemonSet node-observability-ds ready: true NodeObservabilityMachineConfig ready: true' reason: Ready status: "True" type: Ready
NodeObservability
CR run is completed when the reason isReady
and the status isTrue
.
16.3.2. Running the profiling query
To run the profiling query, you must create a NodeObservabilityRun
resource. The profiling query is a blocking operation that fetches CRI-O and Kubelet profiling data for a duration of 30 seconds. After the profiling query is complete, you must retrieve the profiling data inside the container file system /run/node-observability
directory. The lifetime of data is bound to the agent pod through the emptyDir
volume, so you can access the profiling data while the agent pod is in the running
status.
You can request only one profiling query at any point of time.
Prerequisites
- You have installed the Node Observability Operator.
-
You have created the
NodeObservability
custom resource (CR). -
You have access to the cluster with
cluster-admin
privileges.
Procedure
Create a
NodeObservabilityRun
resource file namednodeobservabilityrun.yaml
that contains the following text:apiVersion: nodeobservability.olm.openshift.io/v1alpha2 kind: NodeObservabilityRun metadata: name: nodeobservabilityrun spec: nodeObservabilityRef: name: cluster
Trigger the profiling query by running the
NodeObservabilityRun
resource:$ oc apply -f nodeobservabilityrun.yaml
Review the status of the
NodeObservabilityRun
by running the following command:$ oc get nodeobservabilityrun nodeobservabilityrun -o yaml | yq '.status.conditions'
Example output
conditions: - lastTransitionTime: "2022-07-07T14:57:34Z" message: Ready to start profiling reason: Ready status: "True" type: Ready - lastTransitionTime: "2022-07-07T14:58:10Z" message: Profiling query done reason: Finished status: "True" type: Finished
The profiling query is complete once the status is
True
and type isFinished
.Retrieve the profiling data from the container’s
/run/node-observability
path by running the following bash script:for a in $(oc get nodeobservabilityrun nodeobservabilityrun -o yaml | yq .status.agents[].name); do echo "agent ${a}" mkdir -p "/tmp/${a}" for p in $(oc exec "${a}" -c node-observability-agent -- bash -c "ls /run/node-observability/*.pprof"); do f="$(basename ${p})" echo "copying ${f} to /tmp/${a}/${f}" oc exec "${a}" -c node-observability-agent -- cat "${p}" > "/tmp/${a}/${f}" done done
16.4. Node Observability Operator scripting
Scripting allows you to run pre-configured bash scripts, using the current Node Observability Operator and Node Observability Agent.
These scripts monitor key metrics like CPU load, memory pressure, and worker node issues. They also collect sar reports and custom performance metrics.
16.4.1. Creating the Node Observability custom resource for scripting
You must create and run the NodeObservability
custom resource (CR) before you run the scripting. When you run the NodeObservability
CR, it enables the agent in scripting mode on the compute nodes matching the nodeSelector
label.
Prerequisites
- You have installed the Node Observability Operator.
-
You have installed the OpenShift CLI (
oc
). -
You have access to the cluster with
cluster-admin
privileges.
Procedure
Log in to the OpenShift Container Platform cluster by running the following command:
$ oc login -u kubeadmin https://<host_name>:6443
Switch to the
node-observability-operator
namespace by running the following command:$ oc project node-observability-operator
Create a file named
nodeobservability.yaml
that contains the following content:apiVersion: nodeobservability.olm.openshift.io/v1alpha2 kind: NodeObservability metadata: name: cluster 1 spec: nodeSelector: kubernetes.io/hostname: <node_hostname> 2 type: scripting 3
Create the
NodeObservability
CR by running the following command:$ oc apply -f nodeobservability.yaml
Example output
nodeobservability.olm.openshift.io/cluster created
Review the status of the
NodeObservability
CR by running the following command:$ oc get nob/cluster -o yaml | yq '.status.conditions'
Example output
conditions: conditions: - lastTransitionTime: "2022-07-05T07:33:54Z" message: 'DaemonSet node-observability-ds ready: true NodeObservabilityScripting ready: true' reason: Ready status: "True" type: Ready
The
NodeObservability
CR run is completed when thereason
isReady
andstatus
is"True"
.
16.4.2. Configuring Node Observability Operator scripting
Prerequisites
- You have installed the Node Observability Operator.
-
You have created the
NodeObservability
custom resource (CR). -
You have access to the cluster with
cluster-admin
privileges.
Procedure
Create a file named
nodeobservabilityrun-script.yaml
that contains the following content:apiVersion: nodeobservability.olm.openshift.io/v1alpha2 kind: NodeObservabilityRun metadata: name: nodeobservabilityrun-script namespace: node-observability-operator spec: nodeObservabilityRef: name: cluster type: scripting
ImportantYou can request only the following scripts:
-
metrics.sh
-
network-metrics.sh
(usesmonitor.sh
)
-
Trigger the scripting by creating the
NodeObservabilityRun
resource with the following command:$ oc apply -f nodeobservabilityrun-script.yaml
Review the status of the
NodeObservabilityRun
scripting by running the following command:$ oc get nodeobservabilityrun nodeobservabilityrun-script -o yaml | yq '.status.conditions'
Example output
Status: Agents: Ip: 10.128.2.252 Name: node-observability-agent-n2fpm Port: 8443 Ip: 10.131.0.186 Name: node-observability-agent-wcc8p Port: 8443 Conditions: Conditions: Last Transition Time: 2023-12-19T15:10:51Z Message: Ready to start profiling Reason: Ready Status: True Type: Ready Last Transition Time: 2023-12-19T15:11:01Z Message: Profiling query done Reason: Finished Status: True Type: Finished Finished Timestamp: 2023-12-19T15:11:01Z Start Timestamp: 2023-12-19T15:10:51Z
The scripting is complete once
Status
isTrue
andType
isFinished
.Retrieve the scripting data from the root path of the container by running the following bash script:
#!/bin/bash RUN=$(oc get nodeobservabilityrun --no-headers | awk '{print $1}') for a in $(oc get nodeobservabilityruns.nodeobservability.olm.openshift.io/${RUN} -o json | jq .status.agents[].name); do echo "agent ${a}" agent=$(echo ${a} | tr -d "\"\'\`") base_dir=$(oc exec "${agent}" -c node-observability-agent -- bash -c "ls -t | grep node-observability-agent" | head -1) echo "${base_dir}" mkdir -p "/tmp/${agent}" for p in $(oc exec "${agent}" -c node-observability-agent -- bash -c "ls ${base_dir}"); do f="/${base_dir}/${p}" echo "copying ${f} to /tmp/${agent}/${p}" oc exec "${agent}" -c node-observability-agent -- cat ${f} > "/tmp/${agent}/${p}" done done
16.5. Additional resources
For more information on how to collect worker metrics, see Red Hat Knowledgebase article.