I solved it by restarting kubernetes-worker.

```bash
$ kubectl get pods -A -o wide
NAMESPACE                         NAME                                                     READY   STATUS              RESTARTS   AGE   IP            NODE            NOMINATED NODE   READINESS GATES
default                           hello-kdrtm                                              0/1     ContainerCreating   0          25m   <none>        juju-3f1edd-1   <none>           <none>
ingress-nginx-kubernetes-worker   default-http-backend-kubernetes-worker-cd9b77777-q6g2p   1/1     Running             0          47m   10.1.94.7     juju-3f1edd-1   <none>           <none>
ingress-nginx-kubernetes-worker   nginx-ingress-controller-kubernetes-worker-gv422         1/1     Running             0          47m   10.45.36.91   juju-3f1edd-1   <none>           <none>
kube-system                       coredns-6f867cd986-5lrz9                                 1/1     Running             0          48m   10.1.94.5     juju-3f1edd-1   <none>           <none>
kube-system                       kube-state-metrics-7799879d89-74sp4                      1/1     Running             0          48m   10.1.94.4     juju-3f1edd-1   <none>           <none>
kube-system                       metrics-server-v0.3.6-f6cf867b4-9rzr2                    2/2     Running             0          45m   10.1.94.9     juju-3f1edd-1   <none>           <none>
kubernetes-dashboard              dashboard-metrics-scraper-8458d7fdf6-xf67k               1/1     Running             0          48m   10.1.94.3     juju-3f1edd-1   <none>           <none>
kubernetes-dashboard              kubernetes-dashboard-5784589f96-9m6tj                    1/1     Running             0          48m   10.1.94.2     juju-3f1edd-1   <none>           <none>

$ juju ssh kubernetes-worker/0 -- sudo reboot now
Connection to 10.45.36.91 closed by remote host.
Connection to 10.45.36.91 closed.

$ kubectl get pods -A -o wide
NAMESPACE                         NAME                                                     READY   STATUS      RESTARTS   AGE   IP            NODE            NOMINATED NODE   READINESS GATES
default                           hello-kdrtm                                              0/1     Completed   0          26m   10.2.25.121   juju-3f1edd-1   <none>           <none>
ingress-nginx-kubernetes-worker   default-http-backend-kubernetes-worker-cd9b77777-q6g2p   1/1     Running     1          49m   10.2.25.127   juju-3f1edd-1   <none>           <none>
ingress-nginx-kubernetes-worker   nginx-ingress-controller-kubernetes-worker-gv422         1/1     Running     1          48m   10.45.36.91   juju-3f1edd-1   <none>           <none>
kube-system                       coredns-6f867cd986-5lrz9                                 1/1     Running     1          49m   10.2.25.124   juju-3f1edd-1   <none>           <none>
kube-system                       kube-state-metrics-7799879d89-74sp4                      1/1     Running     1          49m   10.2.25.122   juju-3f1edd-1   <none>           <none>
kube-system                       metrics-server-v0.3.6-f6cf867b4-9rzr2                    2/2     Running     2          47m   10.2.25.125   juju-3f1edd-1   <none>           <none>
kubernetes-dashboard              dashboard-metrics-scraper-8458d7fdf6-xf67k               1/1     Running     1          49m   10.2.25.126   juju-3f1edd-1   <none>           <none>
kubernetes-dashboard              kubernetes-dashboard-5784589f96-9m6tj                    1/1     Running     1          49m   10.2.25.123   juju-3f1edd-1   <none>           <none>
```