Terminate istio sidecar istio-proxy for a kubernetes job / cronjob

We recently started using istio Istio to establish a service-mesh within out Kubernetes landscape.



We now have the problem that jobs and cronjobs do not terminate and keep running forever if we inject the istio istio-proxy sidecar container into them. The istio-proxy should be injected though to establish proper mTLS connections to the services the job needs to talk to and comply with our security regulations.



I also noticed the open issues within Istio (istio/issues/6324) and kubernetes (kubernetes/issues/25908), but both do not seem to provide a valid solution anytime soon.



At first a pre-stop hook seemed suitable to solve this issue, but there is some confusion about this conecpt itself: kubernetes/issues/55807

lifecycle:
preStop:
exec:
command:
...




Bottomline: Those hooks will not be executed if the the container successfully completed.



There are also some relatively new projects on GitHub trying to solve this with a dedicated controller (which I think is the most preferrable approach), but to our team they do not feel mature enough to put them right away into production:




* k8s-controller-sidecars

* K8S-job-sidecar-terminator







In the meantime, we ourselves ended up with the following workaround that execs into the sidecar and sends a SIGTERM signal, but only if the main container finished successfully:

apiVersion: v1
kind: ServiceAccount
metadata:
name: terminate-sidecar-example-service-account
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: terminate-sidecar-example-role
rules:
- apiGroups: [""]
resources: ["pods"]
verbs: ["get","delete"]
- apiGroups: [""]
resources: ["pods/exec"]
verbs: ["create"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: terminate-sidecar-example-rolebinding
subjects:
- kind: ServiceAccount
name: terminate-sidecar-example-service-account
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: terminate-sidecar-example-role
---
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: terminate-sidecar-example-cronjob
labels:
app: terminate-sidecar-example
spec:
schedule: "30 2 * * *"
jobTemplate:
metadata:
labels:
app: terminate-sidecar-example
spec:
template:
metadata:
labels:
app: terminate-sidecar-example
annotations:
sidecar.istio.io/inject: "true"
spec:
serviceAccountName: terminate-sidecar-example-service-account
containers:
- name: ****
image: ****
command:
- "/bin/ash"
- "-c"
args:
- node index.js && kubectl exec -n ${POD_NAMESPACE} ${POD_NAME} -c istio-proxy -- bash -c "sleep 5 && /bin/kill -s TERM 1 &"
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace




So, the ultimate question to all of you is: Do you know of any better workaround, solution, controller, ... that would be less hacky / more suitable to terminate the istio-proxy container once the main container finished its work?