gitlab: add script to create fs and raid for backup partition

This change adds a script to configure the two additional SSDs
to be used as backup partition for /srv/gitlab-backup. As mentioned in
Ie77560b55076c94bec255f5577e2d75492496d08 we were unable to implement
this in partman, so bootstrapping the backup partition was moved to
a dedicated script.

Bug: T330172
Bug: T333674
Change-Id: I8766182572f2a3da2916b85c7ec3226b60ba5119

modules/gitlab/files/gitlab-backup-raid.cfg

@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: Apache-2.0
+# File was created using sfdisk --dump on a properly configured disk.
+label: dos
+label-id: 0x94fe5067
+unit: sectors
+sector-size: 512
+start=        2048, size=  3750746800, type=fd

modules/gitlab/files/provision-backup-fs.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+
+# Provision filesystems and raid for GitLab backup volume
+# GitLab backups are stored on dedicated SSDs /dev/sdc and /dev/sdd
+# https://phabricator.wikimedia.org/T333674
+
+RAID_NAME="/dev/md1"
+MOUNT_POINT="/srv/gitlab-backup"
+
+set -u
+set -x
+
+create_fs() {
+  if [ ! -e $RAID_NAME ]; then
+    sfdisk /dev/sdc < /opt/gitlab-backup-raid.cfg
+    sfdisk /dev/sdd < /opt/gitlab-backup-raid.cfg
+
+    mdadm --create $RAID_NAME --level=mirror --raid-devices=2 /dev/sdc1 /dev/sdd1
+    mkfs.ext4 $RAID_NAME
+  else
+    echo "Raid $RAID_NAME already exists, skipping creation"
+  fi
+
+}
+
+mount_fs() {
+  if [ ! -d "$MOUNT_POINT" ]; then
+    mkdir $MOUNT_POINT
+  else
+    echo "Mountpoint $MOUNT_POINT already exists, skipping creation"
+  fi
+
+  if ! grep -q "^$RAID_NAME $MOUNT_POINT " /etc/fstab ; then
+    echo "$RAID_NAME $MOUNT_POINT ext4 defaults 0 0" >> /etc/fstab
+  else
+    echo "fstab entry for $RAID_NAME at $MOUNT_POINT already exists, skipping creation"
+  fi
+
+  if ! findmnt $MOUNT_POINT; then
+    mount $MOUNT_POINT
+  else
+    echo "$MOUNT_POINT already mounted, skipping mount"
+  fi
+}
+
+create_fs
+mount_fs

modules/gitlab/manifests/init.pp

@@ -150,4 +150,21 @@
         restore_dir_data      => $backup_dir_data,
         restore_interval      => $restore_interval,
     }
+
+    # Install configuration file for gitlab backup partition layout.
+    file {'/opt/gitlab-backup-raid.cfg':
+        mode   => '0744' ,
+        owner  => 'root',
+        group  => 'root',
+        source => 'puppet:///modules/gitlab/gitlab-backup-raid.cfg';
+    }
+
+    # Install scipt to configure backup partition layout and raid.
+    # This script is executed manually while provisioning a new GitLab instance.
+    file {'/opt/provision-backup-fs.sh':
+        mode   => '0744' ,
+        owner  => 'root',
+        group  => 'root',
+        source => 'puppet:///modules/gitlab/provision-backup-fs.sh';
+    }
 }