I am trying to add a init container to a deployment, but I can´t make the env vars work for some reason.
Just to illustrate, this is what I am trying:
initContainers:
- name: init-db
image: mysql:5.7
env:
- name: TEST
value: nada
args: ["echo", "${TEST}"]But no matter what I do, the env vars doesn´t work, the echo always returns ${TEST} instead of nada
Any hint?
According to Kubernetes official documentation, you need to use parentheses $(TEST) for the variable to be expanded in the command or args field. I had an error using brackets because the env vars were not properly expanded on args. Working example:
initContainers:
- name: my-container
image: 'my-image'
envFrom:
- configMapRef:
name: my-config
args:
- '-path=/$(MY_ENV_VAR)'Like the comments and other answer mentioned you need to use shell for ENV substitution properly. therefore, replace the line
args: ["echo", "${TEST}"] in you code to
command: ['sh', '-c', 'echo ${TEST}']
You need to use a shell in order to do ENV var substitution properly. For example:
initContainers:
- name: init-db
image: mysql:5.7
env:
- name: TEST
value: nada
command:
- /bin/sh
- -c
- echo "${TEST}"