Add OSP CP node migration docs

Resolves OSDOCS-3061

Author: maxwelldb

modules/nodes-control-plane-osp-migrating.adoc

@@ -0,0 +1,76 @@
+// Module included in the following assemblies:
+//
+// * nodes/nodes/nodes-nodes-working.adoc
+
+:_content-type: PROCEDURE
+[id="nodes-control-plane-osp-migrating_{context}"]
+= Migrating control plane nodes from one RHOSP host to another
+
+You can run a script that moves a control plane node from one {rh-openstack-first} node to another.
+
+.Prerequisites
+
+* The environment variable `OS_CLOUD` refers to a `clouds` entry that has administrative credentials in a `clouds.yaml` file.
+* The environment variable `KUBECONFIG` refers to a configuration that contains administrative {product-title} credentials.
+
+.Procedure
+
+* From a command line, run the following script:
+
+[source,bash]
+----
+#!/usr/bin/env bash
+
+set -Eeuo pipefail
+
+if [ $# -lt 1 ]; then
+	echo "Usage: '$0 node_name'"
+	exit 64
+fi
+
+# Check for admin OpenStack credentials
+openstack server list --all-projects >/dev/null || { >&2 echo "The script needs OpenStack admin credentials. Exiting"; exit 77; }
+
+# Check for admin OpenShift credentials
+oc adm top node >/dev/null || { >&2 echo "The script needs OpenShift admin credentials. Exiting"; exit 77; }
+
+set -x
+
+declare -r node_name="$1"
+declare server_id
+server_id="$(openstack server list --all-projects -f value -c ID -c Name | grep "$node_name" | cut -d' ' -f1)"
+readonly server_id
+
+# Drain the node
+oc adm cordon "$node_name"
+oc adm drain "$node_name" --delete-emptydir-data --ignore-daemonsets --force
+
+# Power off the server
+oc debug "node/${node_name}" -- chroot /host shutdown -h 1
+
+# Verify the server is shut off
+until openstack server show "$server_id" -f value -c status | grep -q 'SHUTOFF'; do sleep 5; done
+
+# Migrate the node
+openstack server migrate --wait "$server_id"
+
+# Resize the VM
+openstack server resize confirm "$server_id"
+
+# Wait for the resize confirm to finish
+until openstack server show "$server_id" -f value -c status | grep -q 'SHUTOFF'; do sleep 5; done
+
+# Restart the VM
+openstack server start "$server_id"
+
+# Wait for the node to show up as Ready:
+until oc get node "$node_name" | grep -q "^${node_name}[[:space:]]\+Ready"; do sleep 5; done
+
+# Uncordon the node
+oc adm uncordon "$node_name"
+
+# Wait for cluster operators to stabilize
+until oc get co -o go-template='statuses: {{ range .items }}{{ range .status.conditions }}{{ if eq .type "Degraded" }}{{ if ne .status "False" }}DEGRADED{{ end }}{{ else if eq .type "Progressing"}}{{ if ne .status "False" }}PROGRESSING{{ end }}{{ else if eq .type "Available"}}{{ if ne .status "True" }}NOTAVAILABLE{{ end }}{{ end }}{{ end }}{{ end }}' | grep -qv '\(DEGRADED\|PROGRESSING\|NOTAVAILABLE\)'; do sleep 5; done
+----
+
+If the script completes, the control plane machine is migrated to a new {rh-openstack} node.

nodes/nodes/nodes-nodes-working.adoc

@@ -41,3 +41,4 @@ include::modules/nodes-nodes-rtkernel-arguments.adoc[leveloffset=+1]
 endif::openshift-webscale[]
 include::modules/nodes-nodes-cgroups-2.adoc[leveloffset=+1]
 include::modules/nodes-nodes-swap-memory.adoc[leveloffset=+1]
+include::modules/nodes-control-plane-osp-migrating.adoc[leveloffset=+1]