How to apply configuration to a down Mongo pod in Kubernetes cluster? - mongodb

Question

I have a running cluster in Kubernetes (Google Cloud), with 2 pods for 2 frontend apps (Angular), 1 pod backend app (NodeJS) and 1 pod for Mongo DB (currently Down)
In the last code update from git Mongo version updated unintencionally, image tag was not specified in Replication Controller, so it took the latest. This version seems not work.
I get CrashLoopBackOff error in Kubernetes, and the details are:
Failed to start up WiredTiger under any compatibility version. This may be due to an unsupported upgrade or downgrade."}
I have updated the Replication Controller specifying a Mongo version, but when I commit/push the change, workload in Google Cloud is not updating because it's down. The date of last "Created on" is some days ago, not now (see attached images if it's not clear what I'm trying to explain).
My 2 biggest doubts are:
How to force the (re)start of the Mongo Pod (with the added tag specifying the version), in order to fix the down pod issue?
How could I recover the data of the Mongo database in GKE, in order to migrate it quickly?
New Mongo.yaml
apiVersion: v1
kind: Service
metadata:
name: mongo
namespace: sgw-production
labels:
name: mongo
spec:
ports:
- port: 27017
targetPort: 27017
selector:
name: mongo
---
apiVersion: v1
kind: ReplicationController
metadata:
name: mongo-controller
namespace: sgw-production
labels:
name: mongo
spec:
replicas: 1
template:
metadata:
labels:
name: mongo
spec:
containers:
- image: mongo:4.2.10
name: mongo
ports:
- name: mongo
containerPort: 27017
hostPort: 27017
volumeMounts:
- name: mongo-persistent-storage
mountPath: /data/db
volumes:
- name: mongo-persistent-storage
gcePersistentDisk:
pdName: mongo-disk-$CI_ENVIRONMENT_SLUG
fsType: ext4

Answer 1

I answered my own question here with the solution to this issue (copy/paste below):
CrashLoopBackOff (Mongo in Docker/Kubernetes) - Failed to start up WiredTiger under any compatibility version
I solved this issue editing the Replication Controller online from the Google Cloud Console.
Access to: "Kubernetes Engine" > "Workload" > "mongo-controller" > "Managed pods" > "mongo-controller-XXXXX"
...and press EDIT button (in the top navbar). You can edit the configuration online in real time. I simply specified the Mongo version (4.2.10) in the image, and everything woked as expected.
spec:
replicas: 1
selector:
name: mongo
template:
metadata:
creationTimestamp: null
labels:
name: mongo
spec:
containers:
- image: mongo: 4.2.10
(...)