PDB Demo

This is a demo to show the configuration and functionality of a Kubernetes PDB (Pod Disruption Budget).

Setup

Open 3 terminals with the appropriate KUBECONFIG context set

1 for interactive work

Deploy workload

$ kubectl apply -f pdb-tester-deploy.yaml -n pdb-test

Deploy PDB

$ kubectl apply -f pdb-tester-pdb.yaml -n pdb-test

1 for watching the pods

$ watch kubectl get pods -n pdb-test -o wide

1 for watching the PDB

$ watch kubectl get pdb -n pdb-test pdb-tester

Show Sample workload with liveness/readiness probe

$ kubectl get deploy -n pdb-test pdb-tester -o yaml

Show PDB configuration

$ kubectl get pdb -n pdb-test pdb-tester -o yaml

Show Pods running across different nodes
```
$ kubectl get pods -n pdb-test -o wide
```
Show how a single node drain affects the workload
```
$ kubectl drain <node_name> --ignore-daemonsets --delete-local-data
```
- Watching secondary windows showing the pod recreation and wait for probes
- Watch PDB metrics update based on currently unavailable pods

Show concecutive drain operations being blocked by PDB

$ kubectl drain <node_name1> --ignore-daemonsets --delete-local-data; sleep 5; k drain <node_name2> --ignore-daemonsets --delete-local-data