mirror of
https://github.com/openshift/openshift-docs.git
synced 2026-02-07 00:48:01 +01:00
100 lines
2.4 KiB
Plaintext
100 lines
2.4 KiB
Plaintext
// Module included in the following assemblies:
|
|
// * migration/migrating_3_4/troubleshooting-3-4.adoc
|
|
// * migration/migrating_4_1_4/troubleshooting-4-1-4.adoc
|
|
// * migration/migrating_4_2_4/troubleshooting-4-2-4.adoc
|
|
|
|
[id='migration-manually-rolling-back-migration_{context}']
|
|
= Manually rolling back a migration
|
|
|
|
If your application was stopped during a failed migration with the {mtc-full} ({mtc-short}), you must roll it back manually in order to prevent data corruption in the persistent volume.
|
|
|
|
This procedure is not required if the application was not stopped during migration, because the original application is still running on the source cluster.
|
|
|
|
.Procedure
|
|
|
|
. On the target cluster, switch to the migrated project:
|
|
+
|
|
[source,terminal]
|
|
----
|
|
$ oc project <project>
|
|
----
|
|
|
|
. Get the deployed resources:
|
|
+
|
|
[source,terminal]
|
|
----
|
|
$ oc get all
|
|
----
|
|
|
|
. Delete the deployed resources to ensure that the application is not running on the target cluster and accessing data on the persistent volume claim:
|
|
+
|
|
[source,terminal]
|
|
----
|
|
$ oc delete <resource_type>
|
|
----
|
|
|
|
. To stop a daemon set without deleting it, update the `nodeSelector` in the YAML file:
|
|
+
|
|
[source,yaml]
|
|
----
|
|
apiVersion: apps/v1
|
|
kind: DaemonSet
|
|
metadata:
|
|
name: hello-daemonset
|
|
spec:
|
|
selector:
|
|
matchLabels:
|
|
name: hello-daemonset
|
|
template:
|
|
metadata:
|
|
labels:
|
|
name: hello-daemonset
|
|
spec:
|
|
nodeSelector:
|
|
role: worker <1>
|
|
----
|
|
<1> Specify a `nodeSelector` value that does not exist on any node.
|
|
|
|
. Update the reclaim policy for each PV so that unnecessary data is removed. During migration, the reclaim policy for bound PVs is `Retain`, to ensure that data is not lost when an application is removed from the source cluster. You can remove these PVs during rollback.
|
|
+
|
|
[source,yaml]
|
|
----
|
|
apiVersion: v1
|
|
kind: PersistentVolume
|
|
metadata:
|
|
name: pv0001
|
|
spec:
|
|
capacity:
|
|
storage: 5Gi
|
|
accessModes:
|
|
- ReadWriteOnce
|
|
persistentVolumeReclaimPolicy: Retain <1>
|
|
...
|
|
status:
|
|
...
|
|
----
|
|
<1> Specify `Recycle` or `Delete`.
|
|
|
|
. On the source cluster, switch to your migrated project:
|
|
+
|
|
[source,terminal]
|
|
----
|
|
$ oc project <project_name>
|
|
----
|
|
|
|
. Obtain the project's deployed resources:
|
|
+
|
|
[source,terminal]
|
|
----
|
|
$ oc get all
|
|
----
|
|
|
|
. Start one or more replicas of each deployed resource:
|
|
+
|
|
[source,terminal]
|
|
----
|
|
$ oc scale --replicas=1 <resource_type>/<resource_name>
|
|
----
|
|
|
|
. Update the `nodeSelector` of the `DaemonSet` resource to its original value, if you changed it during the procedure.
|