How to delete a pod with Terminating state in OpenShift or Kubernetes Cluster

I am faking some output to explain the situation and solution as shown below.

$ oc get pods
 NAME                   READY     STATUS        RESTARTS   AGE
 jenkins-1-deploy       0/1       Terminating   0          7d
 mongo-db-dev-0         2/2       Running       0          20h
 mongo-db-build         0/1       Completed     0          18h
 mynew-app-1-build      0/1       Terminating   0          7d

We can see pods jenkins-1-deploy and mynew-app-1-build are already instructed to delete but still hanging in Terminating state. So, let’s try the first method by deleting the pod forcefully.

Step 1: Delete pod forcefully

$ oc delete pod jenkins-1-deploy -n myproject --grace-period=0 --force
 warning: Immediate deletion does not wait for confirmation that the running resource has been terminated. The resource may continue to run on the cluster indefinitely.
 pod "jenkins-1-deploy" deleted

I thought it’s deleted as the message says pod “jenkins-1-deploy” deleted . But see what happened when I checked; It’s still there !!!

$ oc get pods
 NAME                   READY     STATUS        RESTARTS   AGE
 jenkins-1-deploy       0/1       Terminating   0          7d
 mongo-db-dev-0         2/2       Running       0          20h
 mongo-db-build         0/1       Completed     0          18h
 mynew-app-1-build      0/1       Terminating   0          7d

Okay, now we realized that, the pod deletion is stuck somewhere. Upon reading documentations we realized that, when you delete an object in kubernetes cluster, you can specify whether the object’s dependents are also deleted automatically. Read more about cascading deletion as well as background vs foreground cascading deletion.

So we have to check below items from pods details.

• Is there any value in object’s deletionTimestamp ?
• Is there any value under object’s metadata.finalizers section “ foregroundDeletion ” ?

There was ! So I have edited the pod ( oc edit ) and removed/replaced those values.

$ oc edit pod jenkins-1-deploy

Step 2: Remove deletionTimestamp

Before:

deletionTimestamp: 2019-01-23T11:40:28Z

After

deletionTimestamp: null

Step 3: Remove items under metadata.finalizers

Before:

...
metadata:
   finalizers:
   - foregroundDeletion
...

After:

...
metadata:
   finalizers: null
...

And save it. (If its asking to save a multiple times as temp files, just save again with :wq .

List down our pods again.

$ oc get pods
 NAME                   READY     STATUS        RESTARTS   AGE
 mongo-db-dev-0         2/2       Running       0          20h
 mongo-db-build         0/1       Completed     0          18h
 mynew-app-1-build      0/1       Terminating   0          7d

It’s gone !!! Do the same for that mynew-app-1-build as well.

Still not working ? Then you may try Step 4

Step 4: Invoke OpenShift API

This is a bit risky method as incorrect usage of this API method may result in unpredictable situations in your OpenShift cluster environment; so be careful.

This method is explained in Red Hat KnowledgeBase with sample instruction set. Let me give some samples below.

We can invoke OpenShift API directly for object manipulation, even for deletion in our case. To delete a pod stuck in ‘ Terminating ‘ or ‘ Unknown ‘ state, you may try following curl sent to the API:

$ echo '{ "propagationPolicy": "Background" }' | curl -k -X DELETE -d @-  -H "Authorization: Bearer
XYZ
" -H 'Accept: application/json' -H 'Content-Type: application/json'  https://
master.example.com:443
/api/v1/namespaces/
myproject
/pods/
my-app-123

Where,

• master_URL = master.example.com
• port = 443
• token = XYZ (this one you have to get using oc whoami -t command)
• pod_name = my-app-123
• namespace = myproject

And check your zombie pods if its still there or not.

That’s all !