Drain master node doesn't succeed without --force option

Author: Michael Burke

modules/graceful-shutdown.adoc

@@ -62,7 +62,7 @@ node/ci-ln-mgdnf4b-72292-n547t-worker-c-vcmtn cordoned
 [source,terminal]
 +
 ----
-$ for node in $(oc get nodes -l node-role.kubernetes.io/worker -o jsonpath='{.items[*].metadata.name}'); do echo ${node} ; oc adm drain ${node} --delete-emptydir-data --ignore-daemonsets=true --timeout=15s ; done
+$ for node in $(oc get nodes -l node-role.kubernetes.io/worker -o jsonpath='{.items[*].metadata.name}'); do echo ${node} ; oc adm drain ${node} --delete-emptydir-data --ignore-daemonsets=true --timeout=15s --force ; done
 ----
 
 . Shut down all of the nodes in the cluster. You can do this from your cloud provider’s web console, or by running the following loop:
@@ -107,4 +107,4 @@ Cluster administrators are responsible for ensuring a clean restart of their own
 [IMPORTANT]
 ====
 If you deployed your cluster on a cloud-provider platform, do not shut down, suspend, or delete the associated cloud resources. If you delete the cloud resources of a suspended virtual machine, {product-title} might not restore successfully.
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