Configure control plane monitoring

New Relic Infrastructure provides Control Plane support for your Kubernetes integration, allowing you to monitor and collect metrics from your cluster's Control Plane components. That data can then be found in New Relic Infrastructure and in New Relic Insights.

Features

We monitor and collect metrics from the following control plane components:

• ETCD: leader information, resident memory size, number of OS threads, consensus proposals data, etc. For a list of supported metrics, see ETCD data.
• API server: rate of apiserver requests, breakdown of apiserver requests by HTTP method and response code, etc. For the complete list of supported metrics, see API server data.
• Scheduler: requested CPU/memory vs available on the node, tolerations to taints, any set affinity or anti-affinity, etc. For the complete list of supported metrics, see Scheduler data.
• Controller manager: resident memory size, number of OS threads created, goroutines currently existing, etc. For the complete list of supported metrics, see Controller manager data.

Compatibility and requirements

• Control plane monitoring requires Kubernetes integration version 1.11.0 or higher.
• Control plane monitoring support is not enabled for managed clusters. This is because providers (EKS, GKE, AKS, etc.) abstract away the concept of master nodes and control plane components, so that access to them is limited or non-existent.
• The unprivileged version of the Kubernetes integration does not support control plane monitoring.
• OpenShift 4.x uses control plane component metric endpoints that are different than the default.

Discovery of master nodes and control plane components

The Kubernetes integration relies on the kubeadm labeling conventions to discover the master nodes and the control plane components. This means that master nodes should be labeled with node-role.kubernetes.io/master="" or kubernetes.io/role="master".

The control plane components should have either the k8s-app or the tier and component labels. Refer to the following table for accepted label combinations and values:

When the integration detects that it is running inside a master node, it tries to find which components are running on the node by looking for pods that match the labels listed in the table above. For every running component, the integration makes a request to its metrics endpoint.

Configuration

Control plane monitoring is automatic for agents running inside master nodes. The only component that requires an extra step to run is ETCD, because it uses mutual TLS authentication (mTLS) for client requests. The API Server can also be configured to be queried using the Secure Port.

ETCD

In order to set mTLS for querying ETCD, there are two configuration options that need to be set:

API server

By default, the API server metrics are queried using the localhost:8080 unsecured endpoint. If this port is disabled, you can also query these metrics over the secure port. To enable this, the following configuration option must be set in the configuration file.

OpenShift configuration

Control plane components on OpenShift 4.x use endpoint URLs that require SSL and service account based authentication. Therefore, the default endpoint URLs can not be used.

To configure control plane monitoring on OpenShift, uncomment the following environment variables in the configuration file. URL values are pre-configured to the default base URLs for the control plane monitoring metrics endpoints in OpenShift 4.x.

- name: "SCHEDULER_ENDPOINT_URL"
  value: "https://localhost:10259
- name: "ETCD_ENDPOINT_URL"
  value: "https://localhost:9979"
- name: "CONTROLLER_MANAGER_ENDPOINT_URL"
  value: "https://localhost:10257"
- name: "API_SERVER_ENDPOINT_URL"
  value: "https://localhost:6443"

Set up mTLS from the ETCD client CA

The instructions below are based on the Kubernetes documentation. For more information, see Managing TLS certificates in a cluster. For OpenShift, see Set up mTLS for ETCD in OpenShift.

To set up mTLS from the ETCD client CA:

1. Download and install the tool cfssl, selecting the correct binaries for your OS from the list.

2. Once installed, execute the following command:

   cat <<EOF | cfssl genkey - | cfssljson -bare server
   {
       "hosts": [
           "localhost"
       ],
       "CN": "newrelic-infra.pod.cluster.local",
       "key": {
           "algo": "ecdsa",
           "size": 256
       }
   }
   EOF

   This command generates two files; server.csr containing the PEM encoded pkcs#10 certification request and server-key.pem containing the PEM encoded key to the certificate to be created.

3. Use the generated certificate authority (CA) of ETCD to sign your CSR. Depending on your cluster configuration, you may already have this information. For default install configuration, download the CA certificate and the private key directly from ETCD with the following commands:

   kubectl cp $(kubectl get pods -l k8s-app=etcd-manager-main -n kube-system -o jsonpath="{.items[0].metadata.name}"):/etc/kubernetes/pki/etcd-manager/etcd-clients-ca.crt ./cacert -n kube-system
   kubectl cp $(kubectl get pods -l k8s-app=etcd-manager-main -n kube-system -o jsonpath="{.items[0].metadata.name}"):/etc/kubernetes/pki/etcd-manager/etcd-clients-ca.key ./cacert.key -n kube-system

   This requires that the etcd-manager-main pod has the label k8s-app=etcd-manager-main, which is a requirement for control plane monitoring . If your etc-manager-main pod is located in a different namespace, change the -n kube-system flags accordingly.

4. With those files downloaded, use the following command to sign your CSRF:

   cfssl sign -ca cacert -ca-key cacert.key server.csr | cfssljson -bare cert
       

5. Create the secret that is used to retrieve the TLS config for making requests to ETC. We recommend renaming the certificate and the private key:

   cp cert.pem cert && cp server-key.pem key
       

   kubectl -n default create secret generic newrelic-infra-etcd-tls-secret --from-file=./cert --from-file=./key --from-file=./cacert

   To ease future installations

   Use the following commands to simultaneously create the CSR, retrieve the CA, generate the certificate by signing the CSR, and create the secret with all the required fields:

       cat <<EOF | cfssl genkey - | cfssljson -bare server && \
       kubectl cp $(kubectl get pods -l k8s-app=etcd-manager-main -n kube-system -o jsonpath="{.items[0].metadata.name}"):/etc/kubernetes/pki/etcd-manager/etcd-clients-ca.crt ./cacert -n kube-system && \
       kubectl cp $(kubectl get pods -l k8s-app=etcd-manager-main -n kube-system -o jsonpath="{.items[0].metadata.name}"):/etc/kubernetes/pki/etcd-manager/etcd-clients-ca.key ./cacert.key -n kube-system && \
       cp server-key.pem key && \
       cfssl sign -ca cacert -ca-key cacert.key server.csr | cfssljson -bare cert && \
       cp cert.pem cert && \
       kubectl -n default create secret generic newrelic-infra-etcd-tls-secret --from-file=./cert --from-file=./key --from-file=./cacert
       {
           "hosts": [
           "localhost"
           ],
           "CN": "newrelic-infra.pod.cluster.local",
           "key": {
               "algo": "ecdsa",
               "size": 256
           }
       }
       EOF

6. The last step is to update the integration configuration in the manifest and apply it.

   In the configuration section, there are two options related to ETCD mTLS:

   • ETCD_TLS_SECRET_NAME with the name of the secret that we just created
   • ETCD_TLS_SECRET_NAMESPACE with the namespace that we used to create the secret

   To complete the installation, add these variables to the container spec of the integration DaemonSet and apply the changes:

   - name: "ETCD_TLS_SECRET_NAME”
       value: "newrelic-infra-etcd-tls-secret"
   - name: "ETCD_TLS_SECRET_NAMESPACE"
       value: "default"

Set up mTLS for ETCD in OpenShift

Follow these instructions to set up mutual TLS authentication for ETCD in OpenShift 4.x:

1. Export the ETCD client certificates from the cluster to an opaque secret. In a default managed OpenShift cluster, the secret is named kube-etcd-client-certs and it is stored in the openshift-monitoring namespace.

     kubectl get secret/kube-etcd-client-certs -n openshift-monitoring -o yaml > etcd-secret.yaml
   

2. Open the secret file and change the keys:
   • Rename the certificate authority to cacert.
   • Rename the client certificate to cert.
   • Rename the client key to key.
3. Optional: change the secret name and namespace to something meaningful.
4. Remove these unnecessary keys in the metadata section:
   • creationTimestamp
   • resourceVersion
   • selfLink
   • uid

5. Install the manifest with its new name and namespace:

   kubectl apply -f etcd-secret.yaml

6. Proceed with step 6 above to configure the required environment variables.

See your data

If the integration has been been set up correctly, the Kubernetes Cluster Explorer contains all the Control Plane components and their status in a dedicated section, as shown below.

one.newrelic.com > Kubernetes Cluster Explorer: Use the Kubernetes Cluster Explorer to monitor and collect metrics from your cluster's Control Plane components

You can also check for Control Plane data with this NRQL query:

SELECT latest(timestamp) FROM K8sApiServerSample, K8sEtcdSample, K8sSchedulerSample, K8sControllerManagerSample FACET entityName where clusterName = 'MY_CLUSTER_NAME'

For more help

Recommendations for learning more:

• See the Docs site's main integrations documentation landing page.
• Browse New Relic's Explorers Hub for community discussions about Kubernetes integrations.
• Review New Relic's infrastructure licenses, data usage limits, and other notices.