cri-o/vendor/k8s.io/kubernetes/examples/newrelic

New Relic Server Monitoring Agent Example

This example shows how to run a New Relic server monitoring agent as a pod in a DaemonSet on an existing Kubernetes cluster.

This example will create a DaemonSet which places the New Relic monitoring agent on every node in the cluster. It's also fairly trivial to exclude specific Kubernetes nodes from the DaemonSet to just monitor specific servers.

Step 0: Prerequisites

This process will create privileged containers which have full access to the host system for logging. Beware of the security implications of this.

If you are using a Salt based KUBERNETES_PROVIDER (gce, vagrant, aws), you should make sure the creation of privileged containers via the API is enabled. Check cluster/saltbase/pillar/privilege.sls.

DaemonSets must be enabled on your cluster. Instructions for enabling DaemonSet can be found here.

Step 1: Configure New Relic Agent

The New Relic agent is configured via environment variables. We will configure these environment variables in a sourced bash script, encode the environment file data, and store it in a secret which will be loaded at container runtime.

The [New Relic Linux Server configuration page] (https://docs.newrelic.com/docs/servers/new-relic-servers-linux/installation-configuration/configuring-servers-linux) lists all the other settings for nrsysmond.

To create an environment variable for a setting, prepend NRSYSMOND_ to its name. For example,

loglevel=debug

translates to

NRSYSMOND_loglevel=debug

Edit examples/newrelic/nrconfig.env and set up the environment variables for your NewRelic agent. Be sure to edit the license key field and fill in your own New Relic license key.

Now, let's vendor the config into a secret.

$ cd examples/newrelic/
$ ./config-to-secret.sh

apiVersion: v1
kind: Secret
metadata:
  name: newrelic-config
type: Opaque
data:
  config: {{config_data}}

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The script will encode the config file and write it to newrelic-config.yaml.

Finally, submit the config to the cluster:

$ kubectl create -f examples/newrelic/newrelic-config.yaml

Step 2: Create the DaemonSet definition.

The DaemonSet definition instructs Kubernetes to place a newrelic sysmond agent on each Kubernetes node.

apiVersion: extensions/v1beta1
kind: DaemonSet
metadata:
  name: newrelic-agent
  labels:
    tier: monitoring
    app: newrelic-agent
    version: v1
spec:
  template:
    metadata:
      labels:
        name: newrelic
    spec:
      # Filter to specific nodes:
      # nodeSelector:
      #  app: newrelic
      hostPID: true
      hostIPC: true
      hostNetwork: true
      containers:
        - resources:
            requests:
              cpu: 0.15
          securityContext:
            privileged: true
          env:
            - name: NRSYSMOND_logfile
              value: "/var/log/nrsysmond.log"
          image: newrelic/nrsysmond
          name: newrelic
          command: [ "bash", "-c", "source /etc/kube-newrelic/config && /usr/sbin/nrsysmond -E -F" ]
          volumeMounts:
            - name: newrelic-config
              mountPath: /etc/kube-newrelic
              readOnly: true
            - name: dev
              mountPath: /dev
            - name: run
              mountPath: /var/run/docker.sock
            - name: sys
              mountPath: /sys
            - name: log
              mountPath: /var/log
      volumes:
        - name: newrelic-config
          secret:
            secretName: newrelic-config
        - name: dev
          hostPath:
              path: /dev
        - name: run
          hostPath:
              path: /var/run/docker.sock
        - name: sys
          hostPath:
              path: /sys
        - name: log
          hostPath:
              path: /var/log

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The daemonset instructs Kubernetes to spawn pods on each node, mapping /dev/, /run/, /sys/, and /var/log to the container. It also maps the secrets we set up earlier to /etc/kube-newrelic/config, and sources them in the startup script, configuring the agent properly.

DaemonSet customization

• To include a custom hostname prefix (or other per-container environment variables that can be generated at run-time), you can modify the DaemonSet command value:

command: [ "bash", "-c", "source /etc/kube-newrelic/config && export NRSYSMOND_hostname=mycluster-$(hostname) && /usr/sbin/nrsysmond -E -F" ]

When the New Relic agent starts, NRSYSMOND_hostname is set using the output of hostname with mycluster prepended.

Known issues

It's a bit cludgy to define the environment variables like we do here in these config files. There is another issue to discuss adding mapping secrets to environment variables in Kubernetes.