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Chapter 5. Migrating from a Standalone Manager to a Self-Hosted Engine

You can convert a standalone Red Hat Virtualization Manager (a separate physical machine, or a virtual machine hosted in a separate virtualization environment) to a self-hosted engine by backing up the standalone Manager and restoring it in a new self-hosted environment.

When you specify a backup file during self-hosted engine deployment, the Manager backup is restored on a new virtual machine, with a dedicated self-hosted engine storage domain. Deploying on a fresh host is highly recommended; if the host used for deployment existed in the backed up environment, it will be removed from the restored database to avoid conflicts in the new environment.

At least two self-hosted engine nodes are required for the Manager virtual machine to be highly available. You can add new nodes, or convert existing hosts.

The migration involves the following key actions:

  1. Back up the original Manager using the engine-backup tool.
  2. Deploy a new self-hosted engine and restore the backup.
  3. Enable the Manager repositories on the new Manager virtual machine.
  4. Convert regular hosts to self-hosted engine nodes that can host the new Manager.

This procedure assumes that you have access and can make changes to the original Manager.

Prerequisites

  • A fresh installation of Red Hat Virtualization Host or Red Hat Enterprise Linux 7, with the required repositories enabled. See Installing Red Hat Virtualization Host or Enabling the Red Hat Enterprise Linux Host Repositories in the Installation Guide.
  • A fully qualified domain name prepared for your Manager and the host. Forward and reverse lookup records must both be set in the DNS. The new Manager must have the same fully qualified domain name as the original Manager.
  • A directory of at least 5 GB on the host, for the RHV-M Appliance. The deployment process will check if /var/tmp has enough space to extract the appliance files. If not, you can specify a different directory or mount external storage. The VDSM user and KVM group must have read, write, and execute permissions on the directory.

  • Prepared storage for a data storage domain dedicated to the Manager virtual machine. This storage domain is created during the self-hosted engine deployment, and must be at least 74 GiB. Highly available storage is recommended. For more information on preparing storage for your deployment, see the Storage chapter of the Administration Guide.

    Important

    If you are using iSCSI storage, the self-hosted engine storage domain must use its own iSCSI target. Any additional storage domains must use a different iSCSI target.

    Warning

    Creating additional data storage domains in the same data center as the self-hosted engine storage domain is highly recommended. If you deploy the self-hosted engine in a data center with only one active data storage domain, and that storage domain is corrupted, you will not be able to add new storage domains or remove the corrupted storage domain; you will have to redeploy the self-hosted engine.

  • The management network (ovirtmgmt by default) must be configured as a VM network, so that it can manage the Manager virtual machine.
  • The original Manager must be updated to the latest minor version; the Manager version in the backup file must match the version of the new Manager. See Updating the Red Hat Virtualization Manager in the Upgrade Guide.

5.1. Backing up the Original Manager

Back up the original Manager using the engine-backup command, and copy the backup file to a separate location so that it can be accessed at any point during the process.

For more information about engine-backup --mode=backup options, see Backing Up and Restoring the Red Hat Virtualization Manager in the Administration Guide.

Procedure

  1. Log in to the original Manager and stop the ovirt-engine service: 

    # systemctl stop ovirt-engine
# systemctl disable ovirt-engine
    Note

    Though stopping the original Manager from running is not obligatory, it is recommended as it ensures no changes are made to the environment after the backup is created. Additionally, it prevents the original Manager and the new Manager from simultaneously managing existing resources.

  2. Run the engine-backup command, specifying the name of the backup file to create, and the name of the log file to create to store the backup log: 

    # engine-backup --mode=backup --file=file_name --log=log_file_name

  3. Copy the files to an external server. In the following example, storage.example.com is the fully qualified domain name of a network storage server that will store the backup until it is needed, and /backup/ is any designated folder or path. 

    # scp -p file_name log_file_name storage.example.com:/backup/

  4. If you do not require the Manager machine for other purposes, unregister it from Red Hat Subscription Manager: 

    # subscription-manager unregister

After backing up the Manager, deploy a new self-hosted engine and restore the backup on the new virtual machine.