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Appendix B. Migrating Databases and Services to a Remote Server

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Although you cannot configure remote databases and services during the automated installation, you can migrate them to a remote server post-installation.

B.1. Migrating the Self-Hosted Engine Database to a Remote Server

You can migrate the engine database of a self-hosted engine to a remote database server after the Red Hat Virtualization Manager has been initially configured. Use engine-backup to create a database backup and restore it on the new database server.

The new database server must have Red Hat Enterprise Linux 7 installed and the required repositories enabled:

Enabling the Red Hat Virtualization Manager Repositories

Register the system with Red Hat Subscription Manager, attach the Red Hat Virtualization Manager subscription, and enable Manager repositories.

Procedure

  1. Register your system with the Content Delivery Network, entering your Customer Portal user name and password when prompted: 

    # subscription-manager register
    Note

    If you are using an IPv6 network, use an IPv6 transition mechanism to access the Content Delivery Network and subscription manager.

  2. Find the Red Hat Virtualization Manager subscription pool and record the pool ID: 

    # subscription-manager list --available

  3. Use the pool ID to attach the subscription to the system: 

    # subscription-manager attach --pool=pool_id
    Note

    To view currently attached subscriptions: 

    # subscription-manager list --consumed

    To list all enabled repositories: 

    # yum repolist

  4. Configure the repositories: 

    # subscription-manager repos \
    --disable='*' \
    --enable=rhel-7-server-rpms \
    --enable=rhel-7-server-supplementary-rpms \
    --enable=rhel-7-server-rhv-4.3-manager-rpms \
    --enable=rhel-7-server-rhv-4-manager-tools-rpms \
    --enable=rhel-7-server-ansible-2.9-rpms \
    --enable=jb-eap-7.2-for-rhel-7-server-rpms

Migrating the Self-Hosted Engine Database to a Remote Server

  1. Log in to a self-hosted engine node and place the environment into global maintenance mode. This disables the High Availability agents and prevents the Manager virtual machine from being migrated during the procedure: 

    # hosted-engine --set-maintenance --mode=global

  2. Log in to the Red Hat Virtualization Manager machine and stop the ovirt-engine service so that it does not interfere with the engine backup: 

    # systemctl stop ovirt-engine.service

  3. Create the engine database backup: 

    # engine-backup --scope=files --scope=db --mode=backup --file=file_name --log=backup_log_name

  4. Copy the backup file to the new database server: 

    # scp /tmp/engine.dump root@new.database.server.com:/tmp

  5. Log in to the new database server and install engine-backup: 

    # yum install ovirt-engine-tools-backup

  6. Restore the database on the new database server. file_name is the backup file copied from the Manager. 

    # engine-backup --mode=restore --scope=files --scope=db --file=file_name --log=restore_log_name --provision-db --no-restore-permissions

  7. Now that the database has been migrated, start the ovirt-engine service: 

    # systemctl start ovirt-engine.service

  8. Log in to a self-hosted engine node and turn off maintenance mode, enabling the High Availability agents: 

    # hosted-engine --set-maintenance --mode=none

B.2. Migrating Data Warehouse to a Separate Machine

This section describes how to migrate the Data Warehouse database and service from the Red Hat Virtualization Manager to a separate machine. Hosting the Data Warehouse service on a separate machine reduces the load on each individual machine, and allows each service to avoid potential conflicts caused by sharing CPU and memory resources with other processes.

You can migrate the Data Warehouse service and connect it with the existing Data Warehouse database (ovirt_engine_history), or you can migrate the Data Warehouse database to the separate machine before migrating the Data Warehouse service. If the Data Warehouse database is hosted on the Manager, migrating the database in addition to the Data Warehouse service further reduces the competition for resources on the Manager machine. You can migrate the database to the same machine onto which you will migrate the Data Warehouse service, or to a machine that is separate from both the Manager machine and the new Data Warehouse service machine.

B.2.1. Migrating the Data Warehouse Database to a Separate Machine

Migrate the Data Warehouse database (ovirt_engine_history) before you migrate the Data Warehouse service. Use engine-backup to create a database backup and restore it on the new database machine. For more information on engine-backup, run engine-backup --help.

To migrate the Data Warehouse service only, see Section B.2.2, “Migrating the Data Warehouse Service to a Separate Machine”.

The new database server must have Red Hat Enterprise Linux 7 installed. Enable the required repositories on the new database server.

Enabling the Red Hat Virtualization Manager Repositories

Register the system with Red Hat Subscription Manager, attach the Red Hat Virtualization Manager subscription, and enable Manager repositories.

Procedure

  1. Register your system with the Content Delivery Network, entering your Customer Portal user name and password when prompted: 

    # subscription-manager register
    Note

    If you are using an IPv6 network, use an IPv6 transition mechanism to access the Content Delivery Network and subscription manager.

  2. Find the Red Hat Virtualization Manager subscription pool and record the pool ID: 

    # subscription-manager list --available

  3. Use the pool ID to attach the subscription to the system: 

    # subscription-manager attach --pool=pool_id
    Note

    To view currently attached subscriptions: 

    # subscription-manager list --consumed

    To list all enabled repositories: 

    # yum repolist

  4. Configure the repositories: 

    # subscription-manager repos \
    --disable='*' \
    --enable=rhel-7-server-rpms \
    --enable=rhel-7-server-supplementary-rpms \
    --enable=rhel-7-server-rhv-4.3-manager-rpms \
    --enable=rhel-7-server-rhv-4-manager-tools-rpms \
    --enable=rhel-7-server-ansible-2.9-rpms \
    --enable=jb-eap-7.2-for-rhel-7-server-rpms
Migrating the Data Warehouse Database to a Separate Machine

  1. Create a backup of the Data Warehouse database and configuration files on the Manager: 

    # engine-backup --mode=backup --scope=dwhdb --scope=files --file=file_name --log=log_file_name

  2. Copy the backup file from the Manager to the new machine: 

    # scp /tmp/file_name root@new.dwh.server.com:/tmp

  3. Install engine-backup on the new machine: 

    # yum install ovirt-engine-tools-backup

  4. Install the PostgreSQL server package: 

    # yum install rh-postgresql10 rh-postgresql10-postgresql-contrib

  5. Initialize the PostgreSQL database, start the postgresql service, and ensure that this service starts on boot: 

    # scl enable rh-postgresql10 -- postgresql-setup --initdb
# systemctl enable rh-postgresql10-postgresql
# systemctl start rh-postgresql10-postgresql

  6. Restore the Data Warehouse database on the new machine. file_name is the backup file copied from the Manager. 

    # engine-backup --mode=restore --scope=files --scope=dwhdb --file=file_name --log=log_file_name --provision-dwh-db --no-restore-permissions

The Data Warehouse database is now hosted on a separate machine from that on which the Manager is hosted. After successfully restoring the Data Warehouse database, a prompt instructs you to run the engine-setup command. Before running this command, migrate the Data Warehouse service.

B.2.2. Migrating the Data Warehouse Service to a Separate Machine

You can migrate the Data Warehouse service installed and configured on the Red Hat Virtualization Manager to a separate machine. Hosting the Data Warehouse service on a separate machine helps to reduce the load on the Manager machine.

Notice that this procedure migrates the Data Warehouse service only.

To migrate the Data Warehouse database (ovirt_engine_history) prior to migrating the Data Warehouse service, see Section B.2.1, “Migrating the Data Warehouse Database to a Separate Machine”.

Prerequisites

  • You must have installed and configured the Manager and Data Warehouse on the same machine.

  • To set up the new Data Warehouse machine, you must have the following:

    • The password from the Manager’s /etc/ovirt-engine/engine.conf.d/10-setup-database.conf file.
    • Allowed access from the Data Warehouse machine to the Manager database machine’s TCP port 5432.
    • The username and password for the Data Warehouse database from the Manager’s /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/10-setup-database.conf file. If you migrated the ovirt_engine_history database using Section B.2.1, “Migrating the Data Warehouse Database to a Separate Machine”, the backup includes these credentials, which you defined during the database setup on that machine.

Installing this scenario requires four steps:

  1. Setting up the New Data Warehouse Machine
  2. Stopping the Data Warehouse service on the Manager machine
  3. Configuring the new Data Warehouse machine
  4. Disabling the Data Warehouse package on the Manager machine

B.2.2.1. Setting up the New Data Warehouse Machine

Enable the Red Hat Virtualization repositories and install the Data Warehouse setup package on a Red Hat Enterprise Linux 7 machine:

  1. Enable the required repositories:

    1. Register your system with the Content Delivery Network, entering your Customer Portal user name and password when prompted: 

      # subscription-manager register

    2. Find the Red Hat Virtualization Manager subscription pool and record the pool ID: 

      # subscription-manager list --available

    3. Use the pool ID to attach the subscription to the system: 

      # subscription-manager attach --pool=pool_id

    4. Configure the repositories: 

      # subscription-manager repos \
    --disable='*' \
    --enable=rhel-7-server-rpms \
    --enable=rhel-7-server-supplementary-rpms \
    --enable=rhel-7-server-rhv-4.3-manager-rpms \
    --enable=rhel-7-server-rhv-4-manager-tools-rpms \
    --enable=rhel-7-server-ansible-2.9-rpms \
    --enable=jb-eap-7.2-for-rhel-7-server-rpms

  2. Ensure that all packages currently installed are up to date: 

    # yum update

  3. Install the ovirt-engine-dwh-setup package: 

    # yum install ovirt-engine-dwh-setup

B.2.2.2. Stopping the Data Warehouse Service on the Manager Machine

  1. Stop the Data Warehouse service: 

    # systemctl stop ovirt-engine-dwhd.service

  2. If the database is hosted on a remote machine, you must manually grant access by editing the postgres.conf file. Edit the /var/opt/rh/rh-postgresql10/lib/pgsql/data/postgresql.conf file and modify the listen_addresses line so that it matches the following: 

    listen_addresses = '*'

    If the line does not exist or has been commented out, add it manually.

    If the database is hosted on the Manager machine and was configured during a clean setup of the Red Hat Virtualization Manager, access is granted by default.

    See Section B.2.1, “Migrating the Data Warehouse Database to a Separate Machine” for more information on how to configure and migrate the Data Warehouse database.

  3. Restart the postgresql service: 

    # systemctl restart rh-postgresql10-postgresql

B.2.2.3. Configuring the New Data Warehouse Machine

The order of the options or settings shown in this section may differ depending on your environment.

  1. If you are migrating both the ovirt_engine_history database and the Data Warehouse service to the same machine, run the following, otherwise proceed to the next step. 

    # sed -i '/^ENGINE_DB_/d' \
        /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/10-setup-database.conf

# sed -i \
     -e 's;^\(OVESETUP_ENGINE_CORE/enable=bool\):True;\1:False;' \
     -e '/^OVESETUP_CONFIG\/fqdn/d' \
     /etc/ovirt-engine-setup.conf.d/20-setup-ovirt-post.conf

  2. Run the engine-setup command to begin configuration of Data Warehouse on the machine: 

    # engine-setup

  3. Press Enter to configure Data Warehouse: 

    Configure Data Warehouse on this host (Yes, No) [Yes]:

  4. Press Enter to accept the automatically detected host name, or enter an alternative host name and press Enter: 

    Host fully qualified DNS name of this server [autodetected host name]:

  5. Press Enter to automatically configure the firewall, or type No and press Enter to maintain existing settings: 

    Setup can automatically configure the firewall on this system.
Note: automatic configuration of the firewall may overwrite current settings.
Do you want Setup to configure the firewall? (Yes, No) [Yes]:

    If you choose to automatically configure the firewall, and no firewall managers are active, you are prompted to select your chosen firewall manager from a list of supported options. Type the name of the firewall manager and press Enter. This applies even in cases where only one option is listed.

  6. Enter the fully qualified domain name and password for the Manager. Press Enter to accept the default values in each other field: 

    Host fully qualified DNS name of the engine server []: engine-fqdn
Setup needs to do some actions on the remote engine server. Either automatically, using ssh as root to access it, or you will be prompted to manually perform each such action.
Please choose one of the following:
1 - Access remote engine server using ssh as root
2 - Perform each action manually, use files to copy content around
(1, 2) [1]:
ssh port on remote engine server [22]:
root password on remote engine server engine-fqdn: password

  7. Enter the FQDN and password for the Manager database machine. Press Enter to accept the default values in each other field: 

    Engine database host []: manager-db-fqdn
Engine database port [5432]:
Engine database secured connection (Yes, No) [No]:
Engine database name [engine]:
Engine database user [engine]:
Engine database password: password

  8. Confirm your installation settings: 

    Please confirm installation settings (OK, Cancel) [OK]:

The Data Warehouse service is now configured on the remote machine. Proceed to disable the Data Warehouse service on the Manager machine.

B.2.2.4. Disabling the Data Warehouse Service on the Manager Machine

  1. On the Manager machine, restart the Manager: 

    # service ovirt-engine restart

  2. Run the following command to modify the file /etc/ovirt-engine-setup.conf.d/20-setup-ovirt-post.conf and set the options to False: 

    # sed -i \
     -e 's;^\(OVESETUP_DWH_CORE/enable=bool\):True;\1:False;' \
     -e 's;^\(OVESETUP_DWH_CONFIG/remoteEngineConfigured=bool\):True;\1:False;' \
     /etc/ovirt-engine-setup.conf.d/20-setup-ovirt-post.conf

  3. Disable the Data Warehouse service: 

    # systemctl disable ovirt-engine-dwhd.service

  4. Remove the Data Warehouse files: 

    # rm -f /etc/ovirt-engine-dwh/ovirt-engine-dwhd.conf.d/* .conf /var/lib/ovirt-engine-dwh/backups/*

The Data Warehouse service is now hosted on a separate machine from the Manager.

B.3. Migrating the Websocket Proxy to a Separate Machine

Important

The websocket proxy and noVNC are Technology Preview features only. Technology Preview features are not supported with Red Hat production service-level agreements (SLAs) and might not be functionally complete, and Red Hat does not recommend using them for production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information see Red Hat Technology Preview Features Support Scope.

For security or performance reasons the websocket proxy can run on a separate machine that does not run the Red Hat Virtualization Manager. The procedure to migrate the websocket proxy from the Manager machine to a separate machine involves removing the websocket proxy configuration from the Manager machine, then installing the proxy on the separate machine.

The engine-cleanup command can be used to remove the websocket proxy from the Manager machine:

Removing the Websocket Proxy from the Manager machine

  1. On the Manager machine, run engine-cleanup to remove the required configuration. 

    # engine-cleanup

  2. Type No when asked to remove all components and press Enter. 

    Do you want to remove all components? (Yes, No) [Yes]: No

  3. Type No when asked to remove the engine and press Enter. 

    Do you want to remove the engine? (Yes, No) [Yes]: No

  4. Type Yes when asked to remove the websocket proxy and press Enter. 

    Do you want to remove the WebSocket proxy? (Yes, No) [No]: Yes

    Select No if asked to remove any other components.

Installing a Websocket Proxy on a Separate Machine

Important

The websocket proxy and noVNC are Technology Preview features only. Technology Preview features are not supported with Red Hat production service-level agreements (SLAs) and might not be functionally complete, and Red Hat does not recommend using them for production. These features provide early access to upcoming product features, enabling customers to test functionality and provide feedback during the development process. For more information see Red Hat Technology Preview Features Support Scope.

The websocket proxy allows users to connect to virtual machines through a noVNC console. The noVNC client uses websockets to pass VNC data. However, the VNC server in QEMU does not provide websocket support, so a websocket proxy must be placed between the client and the VNC server. The proxy can run on any machine that has access to the network, including the the Manager machine.

For security and performance reasons, users may want to configure the websocket proxy on a separate machine.

Procedure

  1. Install the websocket proxy: 

    # yum install ovirt-engine-websocket-proxy

  2. Run the engine-setup command to configure the websocket proxy. 

    # engine-setup
    Note

    If the rhvm package has also been installed, choose No when asked to configure the Manager (Engine) on this host.

  3. Press Enter to allow engine-setup to configure a websocket proxy server on the machine. 

    Configure WebSocket Proxy on this machine? (Yes, No) [Yes]:

  4. Press Enter to accept the automatically detected host name, or enter an alternative host name and press Enter. Note that the automatically detected host name may be incorrect if you are using virtual hosts: 

    Host fully qualified DNS name of this server [host.example.com]:

  5. Press Enter to allow engine-setup to configure the firewall and open the ports required for external communication. If you do not allow engine-setup to modify your firewall configuration, then you must manually open the required ports. 

    Setup can automatically configure the firewall on this system.
Note: automatic configuration of the firewall may overwrite current settings.
Do you want Setup to configure the firewall? (Yes, No) [Yes]:

  6. Enter the FQDN of the Manager machine and press Enter. 

    Host fully qualified DNS name of the engine server []: manager.example.com

  7. Press Enter to allow engine-setup to perform actions on the Manager machine, or press 2 to manually perform the actions. 

    Setup will need to do some actions on the remote engine server. Either automatically, using ssh as root to access it, or you will be prompted to manually perform each such action.
Please choose one of the following:
1 - Access remote engine server using ssh as root
2 - Perform each action manually, use files to copy content around
(1, 2) [1]:

    1. Press Enter to accept the default SSH port number, or enter the port number of the Manager machine. 

      ssh port on remote engine server [22]:

    2. Enter the root password to log in to the Manager machine and press Enter. 

      root password on remote engine server engine_host.example.com:

  8. Select whether to review iptables rules if they differ from the current settings. 

    Generated iptables rules are different from current ones.
Do you want to review them? (Yes, No) [No]:

  9. Press Enter to confirm the configuration settings. 

    --== CONFIGURATION PREVIEW ==--

Firewall manager                        : iptables
Update Firewall                         : True
Host FQDN                               : host.example.com
Configure WebSocket Proxy               : True
Engine Host FQDN                        : engine_host.example.com

Please confirm installation settings (OK, Cancel) [OK]:

    Instructions are provided to configure the Manager machine to use the configured websocket proxy. 

    Manual actions are required on the engine host
in order to enroll certs for this host and configure the engine about it.

Please execute this command on the engine host:
   engine-config -s WebSocketProxy=host.example.com:6100
and than restart the engine service to make it effective

  10. Log in to the Manager machine and execute the provided instructions. 

    # engine-config -s WebSocketProxy=host.example.com:6100
# systemctl restart ovirt-engine.service
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