Chapter 2. Backing up the control plane nodes

To back up the control plane nodes, you configure the backup node, install the Relax-and-Recover tool on the control plane nodes, and create the backup image. You can create backups as a part of your regular environment maintenance.

In addition, you must back up the control plane nodes before performing updates or upgrades. You can use the backups to restore the control plane nodes to their previous state if an error occurs during an update or upgrade.

2.1. Supported backup formats and protocols

The undercloud and backup and restore process uses the open-source tool Relax-and-Recover (ReaR) to create and restore bootable backup images. ReaR is written in Bash and supports multiple image formats and multiple transport protocols.

The following list shows the backup formats and protocols that Red Hat OpenStack Platform supports when you use ReaR to back up and restore the undercloud and control plane.

Bootable media formats
  • ISO
File transport protocols
  • SFTP
  • NFS

2.2. Installing and configuring an NFS server on the backup node

You can install and configure a new NFS server to store the backup file. To install and configure an NFS server on the backup node, create an inventory file, create an SSH key, and run the openstack undercloud backup command with the NFS server options.

Important
  • If you previously installed and configured an NFS or SFTP server, you do not need to complete this procedure. You enter the server information when you set up ReaR on the node that you want to back up.
  • By default, the Relax and Recover (ReaR) IP address parameter for the NFS server is 192.168.24.1. You must add the parameter tripleo_backup_and_restore_server to set the IP address value that matches your environment.

Procedure

  1. On the undercloud node, source the undercloud credentials:

    [stack@undercloud ~]$ source stackrc
    (undercloud) [stack@undercloud ~]$
  2. On the undercloud node, create an inventory file for the backup node:

    (undercloud) [stack@undercloud ~]$ cat <<'EOF'> ~/nfs-inventory.yaml
    [BackupNode]
    <backup_node> ansible_host=<ip_address> ansible_user=<user>
    EOF

    Replace <ip_address> and <user> with the values that apply to your environment.

  3. Copy the public SSH key from the undercloud node to the backup node.

    (undercloud) [stack@undercloud ~]$ ssh-copy-id -i ~/.ssh/id_rsa.pub <backup_node>

    Replace <backup_node> with the path and name of the backup node.

  4. Configure the NFS server on the backup node:

    (undercloud) [stack@undercloud ~]$ openstack undercloud backup --setup-nfs --extra-vars /home/stack/bar-vars.yaml --inventory /home/stack/nfs-inventory.yaml

2.3. Installing ReaR on the control plane nodes

Before you create a backup of the overcloud control plane, install and configure Relax and Recover (ReaR) on each of the control plane nodes.

Important

Due to a known issue, the ReaR backup of overcloud nodes continues even if a Controller node is down. Ensure that all your Controller nodes are running before you run the ReaR backup. A fix is planned for a later Red Hat OpenStack Platform (RHOSP) release. For more information, see BZ#2077335 - Back up of the overcloud ctlplane keeps going even if one controller is unreachable.

Prerequisites

Procedure

  1. On the undercloud node, source the undercloud credentials:

    [stack@undercloud ~]$ source stackrc
  2. If you have not done so before, create an inventory file and use the tripleo-ansible-inventory command to generate a static inventory file that contains hosts and variables for all the overcloud nodes:

    (undercloud) [stack@undercloud ~]$ tripleo-ansible-inventory \
    --ansible_ssh_user heat-admin \
    --static-yaml-inventory /home/stack/tripleo-inventory.yaml
  3. In the bar-vars.yaml file, configure the backup storage location. Follow the appropriate steps for your NFS server or SFTP server.

    1. If you use an NFS server, add the following parameters to the bar-vars.yaml file:

      tripleo_backup_and_restore_server: <ip_address>
      tripleo_backup_and_restore_shared_storage_folder: <backup_server_dir_path>
      tripleo_backup_and_restore_output_url: "nfs://{{ tripleo_backup_and_restore_server }}{{ tripleo_backup_and_restore_shared_storage_folder }}"
      tripleo_backup_and_restore_backup_url: "nfs://{{ tripleo_backup_and_restore_server }}{{ tripleo_backup_and_restore_shared_storage_folder }}"

      Replace <ip_address>`and `<backup_server_dir_path>. The default value for tripleo_backup_and_restore_server parameter value is 192.168.24.1.

    2. If you use an SFTP server, add the tripleo_backup_and_restore_output_url parameter and set the values of the URL and credentials of the SFTP server:

      tripleo_backup_and_restore_output_url: sftp://<user>:<password>@<backup_node>/
      tripleo_backup_and_restore_backup_url: iso:///backup/

      Replace <user>, <password>, and <backup_node> with the backup node URL and credentials.

  4. Install ReaR on the control plane nodes:

    (undercloud) [stack@undercloud ~]$ openstack overcloud backup --setup-rear --extra-vars /home/stack/bar-vars.yaml --inventory /home/stack/tripleo-inventory.yaml
  5. If your system uses the UEFI boot loader, perform the following steps on the control plane nodes:

    1. Install the following tools:

      $ sudo dnf install dosfstools efibootmgr
    2. Enable UEFI backup in the ReaR configuration file located in /etc/rear/local.conf by replacing the USING_UEFI_BOOTLOADER parameter value 0 with the value 1.

2.4. Configuring Open vSwitch (OVS) interfaces for backup

If you use an Open vSwitch (OVS) bridge in your environment, you must manually configure the OVS interfaces before you create a backup of the undercloud or control plane nodes. The restoration process uses this information to restore the network interfaces.

Procedure

  • In the /etc/rear/local.conf file, add the NETWORKING_PREPARATION_COMMANDS parameter in the following format:

    NETWORKING_PREPARATION_COMMANDS=('<command_1>' '<command_2>' ...')

    Replace <command_1> and <command_2> with commands that configure the network interface names or IP addresses. For example, you can add the ip link add br-ctlplane type bridge command to configure the control plane bridge name or add the ip link set eth0 up command to set the name of the interface. You can add more commands to the parameter based on your network configuration.

2.5. Creating a backup of the control plane nodes

To create a backup of the control plane nodes, use the openstack overcloud backup command. You can then use the backup to restore the control plane nodes to their previous state in case the nodes become corrupted or inaccessible. The backup of the control plane nodes includes the backup of the database that runs on the control plane nodes.

Prerequisites

Procedure

  1. Locate the config-drive partition on each control plane node:

    [stack@undercloud ~]$ lsblk
    NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
    vda    253:0    0   55G  0 disk
    ├─vda1 253:1    0    1M  0 part            1
    ├─vda2 253:2    0  100M  0 part /boot/efi
    └─vda3 253:3    0 54.9G  0 part /
    1
    The config-drive partition is the 1M partition that is not mounted.
  2. On each control plane node, back up the config-drive partition of each node as the root user:

    [root@controller-x ~]# dd if=<config_drive_partition> of=/mnt/config-drive

    Replace <config_drive_partition> with the name of the config-drive partition that you located in step 1.

  3. On the undercloud node, source the undercloud credentials:

    [stack@undercloud ~]$ source stackrc
  4. If you have not done so before, use the tripleo-ansible-inventory command to generate a static inventory file that contains hosts and variables for all the overcloud nodes:

    (undercloud) [stack@undercloud ~]$ tripleo-ansible-inventory \
    --ansible_ssh_user heat-admin \
    --static-yaml-inventory /home/stack/tripleo-inventory.yaml
  5. Create a backup of the control plane nodes:

    (undercloud) [stack@undercloud ~]$ openstack overcloud backup --inventory /home/stack/tripleo-inventory.yaml

    The backup process runs sequentially on each control plane node without disrupting the service to your environment.

2.6. Scheduling control plane node backups with cron

You can schedule backups of the control plane nodes with ReaR by using the Ansible backup-and-restore role. You can view the logs in the /var/log/rear-cron directory.

Prerequisites

Procedure

  1. To schedule a backup of your control plane nodes, run the following command. The default schedule is Sundays at midnight:

    openstack overcloud backup --cron
  2. Optional: Customize the scheduled backup according to your deployment:

    • To change the default backup schedule, pass a different cron schedule on the tripleo_backup_and_restore_cron parameter:

      openstack overcloud backup --cron --extra-vars
      '{"tripleo_backup_and_restore_cron": "0 0 * * 0"}'
    • To define additional parameters that are added to the backup command when cron runs the scheduled backup, pass the tripleo_backup_and_restore_cron_extra parameter to the backup command, as shown in the following example:

      openstack overcloud backup --cron --extra-vars '{"tripleo_backup_and_restore_cron_extra":"--extra-vars bar-vars.yaml --inventory /home/stack/tripleo-inventory.yaml"}'
    • To change the default user that executes the backup, pass the tripleo_backup_and_restore_cron_user parameter to the backup command, as shown in the following example:

      openstack overcloud backup --cron --extra-vars '{"tripleo_backup_and_restore_cron_user": "root"}