Red Hat Summit Red Hat SummitSupportConsoleDevelopersStart a trialContact

Chapter 3. Install and Configure ReaR

To back up the undercloud and the overcloud control plane, you must first install and configure Relax and Recover (ReaR) on the undercloud and on each Control Plane node.

3.1. Install the Required Packages
Copy link

The Undercloud and Control Plane Back Up and Restore procedure requires the installation of the Relax and Recover (ReaR) packages and packages for generating ISO images on the undercloud node and on each Control Plane node.

  1. Install the required packages on the undercloud and on each Control Plane node. For example: 

    [root@controller-x ~]# yum install rear genisoimage nfs-utils -y
    Copy to Clipboard Toggle word wrap

  2. Create a backup directory on the undercloud and on each Control Plane node. For example: 

    [root@controller-x ~]# mkdir -p /ctl_plane_backups
    Copy to Clipboard Toggle word wrap

  3. Mount the ctl_plane_backups NFS directory from the backup node running NFS on the undercloud and on each Control Plane node. For example: 

    [root@controller-x ~]# mount -t nfs  <ip-addr>:/ctl_plane_backups /ctl_plane_backups
    Copy to Clipboard Toggle word wrap

    Replace <ip-addr> with the IP address of the backup node running the NFS server.

3.2. Create the Configuration Files
Copy link

As root on the undercloud and on each Control Plane node, perform the following steps:

  1. Create the ReaR configuration file. 

    [root@controller-x ~]# mkdir -p /etc/rear
[root@controller-x ~]# tee -a "/etc/rear/local.conf" > /dev/null <<'EOF'
OUTPUT=ISO
OUTPUT_URL=nfs://{{nfs_server_ip}}/ctl_plane_backups
ISO_PREFIX={{SERVER_NAME-X}}
BACKUP=NETFS
BACKUP_PROG_COMPRESS_OPTIONS=( --gzip )
BACKUP_PROG_COMPRESS_SUFFIX=".gz"
BACKUP_PROG_EXCLUDE=( '/tmp/*' '/data/*' )
BACKUP_URL=nfs://{{nfs_server_ip}}/ctl_plane_backups
BACKUP_PROG_EXCLUDE=("${BACKUP_PROG_EXCLUDE[@]}" '/media' '/var/tmp' '/var/crash')
BACKUP_PROG_OPTIONS+=( --anchored --xattrs-include='*.*' --xattrs )
EOF
    Copy to Clipboard Toggle word wrap

    Replace {{SERVER_NAME-X}} with the hostname of the node. For example, if the node hostname is controller-0, replace {{SERVER_NAME-X}} with controller-0. Replace {{nfs_server_ip}} with the IP address of the backup node running the NFS server configured in Chapter 2, Prepare the Backup Node.

    Important

    If the undercloud or Control Plane nodes use UEFI as their boot mode, you MUST add USING_UEFI_BOOTLOADER=1 to the configuration file too.

  2. Create the rescue.conf file. 

    [root@controller-x ~]# tee  -a "/etc/rear/rescue.conf" > /dev/null <<'EOF'
BACKUP_PROG_OPTIONS+=( --anchored --xattrs-include='*.*' --xattrs )
EOF
    Copy to Clipboard Toggle word wrap
Back to top
Red Hat logoGithubredditYoutubeTwitter

Learn

Try, buy, & sell

Communities

About Red Hat Documentation

We help Red Hat users innovate and achieve their goals with our products and services with content they can trust. Explore our recent updates.

Making open source more inclusive

Red Hat is committed to replacing problematic language in our code, documentation, and web properties. For more details, see the Red Hat Blog.

About Red Hat

We deliver hardened solutions that make it easier for enterprises to work across platforms and environments, from the core datacenter to the network edge.

Theme

© 2025 Red Hat