After deleting all worker nodes, why don't my pods start on new worker nodes?

Virtual Private Cloud Classic infrastructure

You deleted all worker nodes in your cluster so that zero worker nodes exist. Then, you added one or more worker nodes. When you run the following command, several pods for Kubernetes components are stuck in the ContainerCreating status, and the calico-node pods are stuck in the CrashLoopBackOff status.

oc -n calico-system get pods

When you delete all worker nodes in your cluster, no worker node exists for the calico-kube-controllers pod to run on. The Calico controller pod's data can't be updated to remove the data of the deleted worker nodes. When the Calico controller pod begins to run again on the new worker nodes, its data is not updated for the new worker nodes, and it does not start the calico-node pods.

Delete the existing calico-node worker node entries so that new pods can be created.

Before you begin: Install the Calico CLI.

Run the ibmcloud oc cluster config command and copy and paste the output to set the KUBECONFIG environment variable. Include the --admin and --network options with the ibmcloud oc cluster config command. The --admin option downloads the keys to access your infrastructure portfolio and run Calico commands on your worker nodes. The --network option downloads the Calico configuration file to run all Calico commands.
```
ibmcloud oc cluster config --cluster <cluster_name_or_ID> --admin --network
```

For the calico-node pods that are stuck in the CrashLoopBackOff status, note the NODE IP addresses.

oc -n calico-system get pods -o wide

In this example output, the calico-node pod can't start on worker node 10.176.48.106.

NAME                                           READY   STATUS              RESTARTS   AGE     IP              NODE            NOMINATED NODE   READINESS GATES
...
calico-kube-controllers-656c5785dd-kc9x2       1/1     Running             0          25h     10.176.48.107   10.176.48.107   <none>           <none>
calico-node-mkqbx                              0/1     CrashLoopBackOff    1851       25h     10.176.48.106   10.176.48.106   <none>           <none>
coredns-7b56dd58f7-7gtzr                       0/1     ContainerCreating   0          25h     172.30.99.82    10.176.48.106   <none>           <none>

Get the IDs of the calico-node worker node entries. Copy the IDs for only the worker node IP addresses that you retrieved in the previous step.
```
calicoctl get nodes -o wide
```
Use the IDs to delete the worker node entries. After you delete the worker node entries, the Calico controller reschedules the calico-node pods on the new worker nodes.
```
calicoctl delete node <node_ID>
```
Verify that the Kubernetes component pods, including the calico-node pods, are now running. It might take a few minutes for the calico-node pods to be scheduled and for new component pods to be created.
```
oc -n calico-system get pods
```

To prevent this error in the future, never delete all worker nodes in your cluster. Always run at least one worker node in your cluster, and if you use Ingress or routes to expose apps, run at least two worker nodes per zone.