Bug 1748844

Description of problem:

MCO uses openshift/kubernetes-drain for draining nodes before rebooting. The library had a serious bug where the apiserver is flooded with requests. The bug has been fixed in https://github.com/openshift/kubernetes-drain/pull/3 but a deadlock fix went in with https://github.com/openshift/kubernetes-drain/pull/4. However, https://github.com/openshift/kubernetes-drain/pull/4 never landed and instead the library has been forked for supportability to cluster-api/pkg/drain.
The MCO has to switch to the cluster-api fork to fix the deadlock and verify the drain fix is in place.


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1.

$ cat pdb.yaml 
apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: nginx-pdb
spec:
  minAvailable: 1
  selector:
    matchLabels:
      "app": "nginx"

$ oc create -f pdb.yaml

$ cat nginxrs.yaml 
apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx

$ oc create -f nginxrs.yaml

2.

$ oc edit mcp/worker <- set "maxUnavailable: 3" in "spec"

# find the node where the nginx pod has landed on

$ oc describe pod nginx-h7q5b | grep -i node

# grab the MCD for that node

$ oc get pods -l k8s-app=machine-config-daemon  --field-selector spec.nodeName=<NODE> -nopenshift-machine-config-operator

# start streaming the logs

$ oc logs -f <MCD_FOR_NODE>

3.

# create a test MC to trigger a drain

$ cat file.yaml                                                                                                                                                                                                                   130 ↵
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: test-file
spec:
  config:
    ignition:
      version: 2.2.0
    storage:
      files:
      - contents:
          source: data:text/plain;charset=utf;base64,c2VydmVyIGZvby5leGFtcGxlLm5ldCBtYXhkZWxheSAwLjQgb2ZmbGluZQpzZXJ2ZXIgYmFyLmV4YW1wbGUubmV0IG1heGRlbGF5IDAuNCBvZmZsaW5lCnNlcnZlciBiYXouZXhhbXBsZS5uZXQgbWF4ZGVsYXkgMC40IG9mZmxpbmUK
        filesystem: root
        mode: 0644
        path: /etc/test

$ oc create -f file.yaml

# now look at the logs from the point above

Actual results:

eviction is tried for the nginx pod over and over w/o timeout 

Expected results:

eviction is tried for the nginx pod over and over but with a 5s delay between requests


Additional info:

Having a pdb=1 and rsreplica=1 is a logical bug also, so it's expected the drain tries over and over, that's not a bug.