Pod fails with ImagePullBackOff error

Post the upgrade of the VMware Telco Cloud Service Assurance in a VMbased deployment, Isitio-edge-ingressgateway pod fails with ImagePullBackOff error.

While upgrading VMware Telco Cloud Service Assurance 2.2 to VMware Telco Cloud Service Assurance 2.3 or VMware Telco Cloud Service Assurance 2.3 to VMware Telco Cloud Service Assurance 2.3.1 in a DarkSite/Airgap environment, if the Isitio-edge-ingressgateway pod fails with ImagePullBackOff Error. Then follow the blow workaround:

Workaround:

Do a decsribe on the istio-edge-ingressway pod as follows:

Kubectl describe pod -n Kafka-edge <istio-edge-ingressgateway-pod>

If the Iimage is pointing to projects.registry.vmware.com, then follow the below steps:

Pause Kafka-edge App reconciliation by adding the following lines under the spec field:
```
 `kubectl edit app kafka-edge`. 
  spec:
  paused: true
  canceled: true
```
Scale down and scale up the istio-ingressgateway pod in Kafka-edge namespace.
```
kubectl scale deployment istio-ingressgateway -n kafka-edge --replicas=0
```
Wait for the scale down to complete. Then Scale up istio-ingressgateway POD:
```
kubectl scale deployment istio-ingressgateway -n kafka-edge --replicas=1
```
Unpause the Kafka-edge app by removing the previously added below lines under spec.
```
`kubectl edit app kafka-edge`
```
Remove the below two lines under spec:
```
paused: true
canceled: true
```
Kafka edge app must be successfully reconciled and the istio-ingressgateway pod must be UP and Running.