feat(nexus3): Allow env vars to be interpolated in INSTALL4J_ADD_VM_PARAMS

[flah00]

Solution

Ensure that the INSTALL4J_ADD_VM_PARAMS environment variable is configured after all others. This allows user defined env vars in Values.env to be interpolated.

Background

I am trying to extract JMX metrics from my Nexus app. We are using datadog. Their advice is to set the pod ip address as an environment variable and then set the JVM RMI hostname as the pod ip.

Kubernetes (or is it helm?) can interpolate environment variables. But the environment variables must be defined before they are used.

WORKS (in pod INSTALL4J_ADD_VM_PARAMS=... -Djava.rmi.server.hostname=1.2.3.4)

  containers:
    - name: foo
      env:
        - name: POD_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP
        - name: INSTALL4J_ADD_VM_PARAMS
          value: ... -Djava.rmi.server.hostname=$(POD_IP)

BROKEN (in pod INSTALL4J_ADD_VM_PARAMS=... -Djava.rmi.server.hostname=$(POD_IP))

  containers:
    - name: foo
      env:
        - name: INSTALL4J_ADD_VM_PARAMS
          value: ... -Djava.rmi.server.hostname=$(POD_IP)
        - name: POD_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP

Work around

To work around this problem, I currently declare env[].name=POD_IP and then env[].name=JAVA_TOOL_OPTIONS.

But I'd prefer to declare all of my JVM options more centrally.

[stevehipwell]

LGTM

[stevehipwell]

@flah00 could you please rebase this?

[stevehipwell]

LGTM

[stevehipwell]

@flah00 sorry, could you rebase again?

[stevehipwell]

LGTM