I want to set an environment variable (I'll just name it ENV_VAR_VALUE) to a container during deployment through Kubernetes.
I have the following in the pod yaml configuration:
...
...
spec:
containers:
- name: appname-service
image: path/to/registry/image-name
ports:
- containerPort: 1234
env:
- name: "ENV_VAR_VALUE"
value: "some.important.value"
...
...The container needs to use the ENV_VAR_VALUE's value.
But in the container's application logs, it's value always comes out empty.
So, I tried checking it's value from inside the container:
$ kubectl exec -it appname-service bash
root@appname-service:/# echo $ENV_VAR_VALUE
some.important.value
root@appname-service:/# So, the value was successfully set.
I imagine it's because the environment variables defined from Kubernetes are set after the container is already initialized.
So, I tried overriding the container's CMD from the pod yaml configuration:
...
...
spec:
containers:
- name: appname-service
image: path/to/registry/image-name
ports:
- containerPort: 1234
env:
- name: "ENV_VAR_VALUE"
value: "some.important.value"
command: ["/bin/bash"]
args: ["-c", "application-command"]
...
...
Even still, the value of ENV_VAR_VALUE is still empty during the execution of the command.
Thankfully, the application has a restart function
-- because when I restart the app, ENV_VAR_VALUE get used successfully.
-- I can at least do some other tests in the mean time.
How should I configure this in Kubernetes so it isn't a tad too late in setting the environment variables?
As requested, here is the Dockerfile.
I apologize for the abstraction...
FROM ubuntu:18.04
RUN apt-get update && apt-get install -y some-dependencies
COPY application-script.sh application-script.sh
RUN ./application-script.sh
# ENV_VAR_VALUE is set in this file which is populated when application-command is executed
COPY app-config.conf /etc/app/app-config.conf
CMD ["/bin/bash", "-c", "application-command"]Why don't you move the
RUN ./application-script.shbelow
COPY app-config.conf /etc/app/app-config.confLooks like the app is running before the env conf is available for it.
You can try also running two commands in Kubernetes POD spec:
(main command): "application-command"
Like this:
containers:
- name: appname-service
image: path/to/registry/image-name
ports:
- containerPort: 1234
command: ["/bin/sh", "-c"]
args:
- source /env/db_cred.env;
application-command;