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xsrv.backup

This role will setup rsnapshot, an incremental backup system.

rsnapshot is a filesystem snapshot utility based on rsync. rsnapshot makes it easy to make periodic snapshots of local machines, and remote machines over ssh. It makes extensive use of hard links whenever possible, to greatly reduce the disk space required. rsnapshot allows running scripts before taking actual snapshots of the filesystem (for example, dumping a database, performing an application data export...)

  • configurable backup sources (local/remote), destinations, scripts and retention policy
  • loads any additional/custom configuration from /etc/rsnapshot.d/*.conf
  • (optional) aggregation of rsnapshot logs to syslog
  • monitoring of time since last successful daily backup

Requirements/dependencies/example playbook

  • See meta/main.yml
  • On hosts that should be backed up, firewall/NAT rules allowing SSH connections from the backup server
# playbook.yml
- hosts: my.CHANGEME.org
  roles:
    - nodiscc.xsrv.common # (optional) base server setup, hardening, firewall, bruteforce prevention
    - nodiscc.xsrv.backup
    - nodiscc.xsrv.monitoring # (optional) rsnapshot log aggregation, health monitoring

See defaults/main.yml for all configuration variables

Usage

  • force running backups immediately: TAGS=utils-backup-now xsrv deploy or ssh -t user@my.example.org sudo rsnapshot daily
  • show the size of backups on the host: ssh -t user@my.example.org sudo du --human-readable --summarize --time /var/backups/srv01/*
  • transfer latest daily backups form the host to the controller (this may take a while): xsrv fetch-backups PROJECT my.CHANGEME.org

Backups size: If a file is completely unchanged between two backups, the second backup will not consume more space on disk (incremental backup, deduplication using hardlinks). If you rename the file or change a single byte, the full file will we backed up again. This can increase disk usage if you keep adding/removing/renaming/editing large files. If you want to free up disk space, and you are certain you will not need to recover files from old backups, you can start by deleting the oldest generations (e.g. xsrv shell then sudo rm -r /var/backups/rsnapshot/monthly.5). You can visualize disk space consumed by each backup generatino using tools such as ncdu or duc provided by the monitoring_utils role.

Local backups are inherently not secure, because the device being backed up is able to delete/compromise its own backups, and backups are stored in the same location as the live data. Local backups still offer a recovery solution for accidental deletion of a specific piece of data, or application bugs. For disaster recovery, prefer remote pull backups from another machine (i.e. setup the backup role on a dedicated machine, and configure it to pull backups from other hosts, see backup data from remote machines). In addition, you should perform periodic copies of the latest backup generation to an offline/offiste storage, using the xsrv fetch-backups command, or manually:

Example Using shell commands: 
rsync --quiet --hard-links --archive --verbose --compress --partial --progress --delete \
--rsh "ssh -p $ansible_ssh_port"
"user@my.example.org:/var/backups/srv01/daily.0" "/path/to/offsite-backups/${inventory_hostname}-daily.0.$(date +%Y-%m-%d)"

Backup data from remote machines:

  • configure the list of hosts, SSH users, ports, paths... in the rsnapshot_remote_backups configuration variable and deploy the role to the backup server.
  • setup a user account on the machine to backup, authorize the backup server's root public SSH key to connect to it (the key is displayed when the backup role is deployed, and a copy is downloaded to "{{ playbook_dir }}/data/public_keys/root@{{ inventory_hostname }}.pub" on the controller), and allow it to run sudo rsync without password.
# example using https://gitlab.com/nodiscc/xsrv/-/tree/master/roles/common
linux_users:
   - name: "rsnapshot"
     groups: [ "ssh-access", "sudo" ]
     comment: "limited user account for remote backups"
     ssh_authorized_keys: ['public_keys/root@backupserver.CHANGEME.org.pub']
     sudo_nopasswd_commands: ['/usr/bin/rsync']
Example using shell commands: 
# upload the backup server's public SSH key to the remote host
user@controller:~ $ rsync -avP public_keys/root@backupserver.CHANGEME.org.pub:
# login to the remote host using SSH
user@controller:~ $ ssh remotehost.CHANGEME.org
# create a limited user account to which the backup server will connect
user@remotehost:~ $ sudo useradd --groups ssh-access,sudo --comment "limited user account for remote backups" rsnapshot
# authorize the backup server's SSH key on the rsnapshot user account
user@remotehost:~ $ sudo mkdir /home/rsnapshot/.ssh && cat root@backupserver.CHANGEME.org.pub | sudo tee -a /home/rsnapshot/.ssh/authorized_keys && sudo chown -R g-rwx /home/rsnapshot/.ssh/
# allow the rsnapshot user to run sudo rsync without password
user@remotehost:~ $ echo 'rsnapshot ALL=(ALL) NOPASSWD: /usr/bin/rsync' | sudo tee -a /etc/sudoers.d/nopasswd && sudo chmod 0660 /etc/sudoers.d/nopasswd

Removing old backup jobs: if a backup job is added at some point, then later removed (for example, removed backup jobs for a decomissionned server), the corresponding files will be kept in later backup generations. To clean up files produced by removed backup jobs, delete the corresponding directory in /var/backups/rsnapshot/*/.

Tags

backup - setup rsnapshot backup utility
rsnapshot-ssh-key - generate ssh key for rsnapshot backup utility
utils-backup-now - (manual) transfer latest daily backups from the host to the controller

References

License

GPLv3