I am using a sidecard pattern for a k8s pod within which there're two containers: the main container and the sidecar container. I'd like to have the pod status depends on the main container only (say if the main container failed/completed, the pod should be in the same status) and discard the sidecard container.
Is there an elegant way to doing this?
Unfortunately the restartPolicy flag applies to all containers in the pod so the simple solution isn’t really going to work. Are you sure your logic shouldn’t be in an initContainer rather than a sidecar? If it does need to be a sidecar, have it sleep forever at the end of your logic.
As per documentation:
Pod is running and has two Containers. Container 1 exits with failure.
Log failure event.
If restartPolicy is:
- Always: Restart Container; Pod phase stays Running.
- OnFailure: Restart Container; Pod phase stays Running.
- Never: Do not restart Container; Pod phase stays Running.
If Container 1 is not running, and Container 2 exits:
Log failure event.
If restartPolicy is:
- Always: Restart Container; Pod phase stays Running.
- OnFailure: Restart Container; Pod phase stays Running.
- Never : Pod phase becomes Failed.
As workaround (partial solution for this problem) with restartPolicy: Never - you can apply the result of livenees probe from the main container to the sidecar container (using using exec, http or tcp probe).
It's not the good solution while working with microservices.
example:
apiVersion: v1
kind: Pod
metadata:
labels:
test: liveness
name: liveness-exec
spec:
containers:
- name: liveness1
image: k8s.gcr.io/busybox
args:
- /bin/sh
- -c
- touch /test-pd/healthy; sleep 30; rm -rf /test-pd/healthy; sleep 30
livenessProbe:
exec:
command:
- cat
- /test-pd/healthy
initialDelaySeconds: 5
periodSeconds: 5
volumeMounts:
- mountPath: /test-pd
name: test-volume
- name: liveness2
image: k8s.gcr.io/busybox
args:
- /bin/sh
- -c
- sleep 120
livenessProbe:
exec:
command:
- cat
- /test-pd2/healthy
initialDelaySeconds: 5
periodSeconds: 5
volumeMounts:
- mountPath: /test-pd2
name: test-volume
restartPolicy: Never
volumes:
- name: test-volume
hostPath:
# directory location on host
path: /data
type: DirectoryPlease let me know if that helped.