Use O/S Env Var for OpenShift Deployment Environment Configuration - openshift

Question

I would like to provide an environment variable to an OpenShift pod and within that variable reference other environment variables defined in the container.
For example, I define an environment variable called JAVA_CMD_LINE in OpenShift and set it to:
$HEAP_SETTING -Djavax.net.ssl.trustStore=/var/.keystore/cacerts -jar abc.jar
Where $HEAP_SETTING is set to -XMX=1G when the container starts.
In my container, there is a startup script that looks like:
java $JAVA_CMD_LINE
What I would expect is that then the container runs, the following is executed:
java -XMX=1G -Djavax.net.ssl.trustStore=/var/.keystore/cacerts -jar abc.jar
But instead what I see is:
java '$HEAP_SETTING' -Djavax.net.ssl.trustStore=/var/.keystore/cacerts -jar abc.jar
How do I provide the variable?
Update: Adding details from the YML file.
spec:
containers:
- env:
- name: OPENSHIFT_ENABLE_OAUTH
value: 'true'
- name: OPENSHIFT_ENABLE_REDIRECT_PROMPT
value: 'true'
- name: KUBERNETES_MASTER
value: 'https://kubernetes.default:443'
- name: KUBERNETES_TRUST_CERTIFICATES
value: 'true'
- name: JAVA_CMD_LINE
value: >-
-Djavax.net.ssl.trustStore=/var/cert/.keystore/cacerts
-Dfile.encoding=UTF8
$HEAP_SETTING
Update 2 - The error that I see:
+ exec java -Djavax.net.ssl.trustStore=/var/jenk-cert/.keystore/cacerts -Djavax.net.ssl.trustStorePassword=changeit -Dfile.encoding=UTF8 '$(HEAP_SETTING)' -Duser.home=/var/lib/jenkins -Djavamelody.application-name=JENKINS -jar /usr/lib/jenkins/jenkins.war
Picked up JAVA_TOOL_OPTIONS: -XX:+UnlockExperimentalVMOptions -XX:+UseCGroupMemoryLimitForHeap -Dsun.zip.disableMemoryMapping=true
Error: Could not find or load main class $(HEAP_SETTING)

Answer 1

Try using:
spec:
containers:
- env:
- name: OPENSHIFT_ENABLE_OAUTH
value: 'true'
- name: OPENSHIFT_ENABLE_REDIRECT_PROMPT
value: 'true'
- name: KUBERNETES_MASTER
value: 'https://kubernetes.default:443'
- name: KUBERNETES_TRUST_CERTIFICATES
value: 'true'
- name: JAVA_CMD_LINE
value: >-
-Djavax.net.ssl.trustStore=/var/cert/.keystore/cacerts
-Dfile.encoding=UTF8
$(HEAP_SETTING)
Any time you are setting the value of an environment variable, if you need to compose the value from other environment variables that are already being set, you can use $(<VARNAME>) in the value.
IOW, use $(HEAP_SETTING) and not just $HEAP_SETTING.
UPDATE 1
Actually this will not work. This is because HEAP_SETTING is not in the set of environment variables you are setting via the deployment config, so it will pass the literal value $(HEAP_SETTING). This can't be used where the environment variable you are trying to use is populated by startup code in the image.