Chapter 1. Migration from OpenShift Container Platform 3 to 4 overview
OpenShift Container Platform 4 clusters are different from OpenShift Container Platform 3 clusters. OpenShift Container Platform 4 clusters contain new technologies and functionality that result in a cluster that is self-managing, flexible, and automated. To learn more about migrating from OpenShift Container Platform 3 to 4 see About migrating from OpenShift Container Platform 3 to 4.
1.1. Differences between OpenShift Container Platform 3 and 4
Before migrating from OpenShift Container Platform 3 to 4, you can check differences between OpenShift Container Platform 3 and 4. Review the following information:
1.2. Planning network considerations
Before migrating from OpenShift Container Platform 3 to 4, review the differences between OpenShift Container Platform 3 and 4 for information about the following areas:
You can migrate stateful application workloads from OpenShift Container Platform 3 to 4 at the granularity of a namespace. To learn more about MTC see Understanding MTC.
If you are migrating from OpenShift Container Platform 3, see About migrating from OpenShift Container Platform 3 to 4 and Installing the legacy Migration Toolkit for Containers Operator on OpenShift Container Platform 3.
1.3. Installing MTC
Review the following tasks to install the MTC:
1.4. Upgrading MTC
You upgrade the Migration Toolkit for Containers (MTC) on OpenShift Container Platform 4.17 by using OLM. You upgrade MTC on OpenShift Container Platform 3 by reinstalling the legacy Migration Toolkit for Containers Operator.
1.5. Reviewing premigration checklists
Before you migrate your application workloads with the Migration Toolkit for Containers (MTC), review the premigration checklists.
1.6. Migrating applications
You can migrate your applications by using the MTC web console or the command line.
1.7. Advanced migration options
You can automate your migrations and modify MTC custom resources to improve the performance of large-scale migrations by using the following options:
1.8. Troubleshooting migrations
You can perform the following troubleshooting tasks:
- Viewing migration plan resources by using the MTC web console
- Viewing the migration plan aggregated log file
- Using the migration log reader
- Accessing performance metrics
-
Using the
must-gather
tool -
Using the Velero CLI to debug
Backup
andRestore
CRs - Using MTC custom resources for troubleshooting
- Checking common issues and concerns
1.9. Rolling back a migration
You can roll back a migration by using the MTC web console, by using the CLI, or manually.
1.10. Uninstalling MTC and deleting resources
You can uninstall the MTC and delete its resources to clean up the cluster.