There is a corner case when blocking Pod termination via a lifecycle
preStop hook, for example by using this StateFulSet:
```yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: web
spec:
selector:
matchLabels:
app: ubi
serviceName: "ubi"
replicas: 1
template:
metadata:
labels:
app: ubi
spec:
terminationGracePeriodSeconds: 1000
containers:
- name: ubi
image: ubuntu:22.04
command: ['sh', '-c', 'echo The app is running! && sleep 360000']
ports:
- containerPort: 80
name: web
lifecycle:
preStop:
exec:
command:
- /bin/sh
- -c
- 'echo aaa; trap : TERM INT; sleep infinity & wait'
```
After creation, downscaling, forced deletion and upscaling of the
replica like this:
```
> kubectl apply -f sts.yml
> kubectl scale sts web --replicas=0
> kubectl delete pod web-0 --grace-period=0 --force
> kubectl scale sts web --replicas=1
```
We will end up having two pods running by the container runtime, while
the API only reports one:
```
> kubectl get pods
NAME READY STATUS RESTARTS AGE
web-0 1/1 Running 0 92s
```
```
> sudo crictl pods
POD ID CREATED STATE NAME NAMESPACE ATTEMPT RUNTIME
e05bb7dbb7e44 12 minutes ago Ready web-0 default 0 (default)
d90088614c73b 12 minutes ago Ready web-0 default 0 (default)
```
When now running `kubectl exec -it web-0 -- ps -ef`, there is a random chance that we hit the wrong
container reporting the lifecycle command `/bin/sh -c echo aaa; trap : TERM INT; sleep infinity & wait`.
This is caused by the container lookup via its name (and no podUID) at:
02109414e8/pkg/kubelet/kubelet_pods.go (L1905-L1914)
And more specifiy by the conversion of the pod result map to a slice in `GetPods`:
02109414e8/pkg/kubelet/kuberuntime/kuberuntime_manager.go (L407-L411)
We now solve that unexpected behavior by tracking the creation time of
the pod and sorting the result based on that. This will cause to always
match the most recently created pod.
Signed-off-by: Sascha Grunert <sgrunert@redhat.com>
It turned out to be unreliable (see
https://github.com/kubernetes/kubernetes/issues/112834). Encoding the data
inside the command as input for base64 is a workaround that is fine for small
amounts of data. It becomes less efficient and/or unusable for large amounts.
- The sub-phases like `kubeadm reset phase cleanup-node` which
could be run independently would be able to support the `dry-run`
mode as well.
- Consistent with the sub-phases which support the `dry-run` mode
already, such as `kubeadm init phase control-plane apiserver`.
- Prepare for the day when each of those sub-phases could be run
independently.
Signed-off-by: Dave Chen <dave.chen@arm.com>
