backy 2.0b3

Synopsis

backy –help

backy scheduler -c CONFIG

backy check -c CONFIG

backy [-b BACKUPDIR ] init

backy [-b BACKUPDIR ] backup TAGS

backy [-b BACKUPDIR ] status

Disaster recovery

$ cd /srv/backy/my-virtual-machine
$ dd if=latest of=/srv/kvm/my-virtual-machine bs=4048000

$ cd /srv/backy/my-virtual-machine
$ backy status
== Revisions
2014-04-25 10:07:51 96d8b001-0ffc-4149-8c35-cf003f5638d6    20.00 GiB   252s
2014-04-25 10:13:20 d95e4f6c-cfef-48ee-aec2-d7c9e91c1bec    24.34 MiB   13s

== Summary
2 revisions
20.02 GiB data (estimated)
$ dd if=96d8b001-0ffc-4149-8c35-cf003f5638d6 of=/srv/kvm/my-virtual-machine bs=4048000

$ cd /srv/backy/my-virtual-machine
$ ls -lah latest
lrwxrwxrwx 1 root root  36 Apr 25 10:13 last -> d95e4f6c-cfef-48ee-aec2-d7c9e91c1bec
$ kpartx -av d95e4f6c-cfef-48ee-aec2-d7c9e91c1bec
add map loop0p1 (253:9): 0 41934815 linear /dev/loop0 8192
$ mkdir /root/restore
$ mount -o ro /dev/mapper/loop0p1 /root/restore
$ cd /root/restore
$ ls
bin  boot  dev  etc  home  lib  lost+found  media  mnt  opt  proc  root  run  sbin  srv  sys  tmp  usr  var

$ cd /srv/backy/my-virtual-machine
$ umount /root/restore
$ kpartx -av d95e4f6c-cfef-48ee-aec2-d7c9e91c1bec

Creating backups

Create a configuration file (see below). Spawn the scheduler with your favourite init system:

backy scheduler -c /path/to/backy.conf

The scheduler runs in the foreground until it is shot by SIGTERM. On resume, the scheduler re-runs missed backup jobs to some degree.

Log output goes to backy.log in the current directory.

Interactive console

Telnet into localhost port 6023 to get a console.

Configuration

Backy’s job scheduler maintains a set of revisions (snapshots) for each configured job according to a schedule. Each revision is marked with a set of tags. A certain number of revisions is kept for each tag.

Refer to examples/backy.conf for a full configuration example. The configuration file is a YAML document with the following top-level sections:

schedules:
    mysched:
        daily:
            interval: 1d
            keep: 9
        weekly:
            interval: 7d
            keep: 5

Backup Sources

Backy comes with a number of plug-ins which define block-file like sources:

• file extracts data from simple image files living on a regular file system.

• ceph pulls data from RBD images using Ceph features like snapshots. Needs environment variables like CEPH_ARGS to provide access IDs.

• flyingcircus is an extension to the ceph source which we use internally on the Flying Circus hosting platform. It uses advanced features like Consul integration.

It should be easy to write plug-ins for additional sources.

Low-level commands

Generally speaking, use the scheduler. In case of need, the following low-level commands can be invoked directly.

Authors

• Daniel Kraft <daniel.kraft@d9t.de>

• Christian Theune <ct@flyingcircus.io>

• Christian Kauhaus <kc@flyingcircus.io>

License

GPLv3

2.0b3 (2015-10-02)

• Improve telnet console.

• If the envionment variable BACKY_FORGET_ABOUT_BTRFS is set, special btrfs features (reflink copies, defrag) are not used. This is intended to run tests on non-btrfs filesystems.

• Provide Nix build script.

• Generate requirements.txt automatically from buildout versions.cfg.

2.0b2 (2015-09-15)

• Introduce scheduler and rework the main backup command. The backy command is now only responsible for dealing with individual backups.

  It does no longer care about scheduling.

  A new daemon and a central configuration file is responsible for that now. However, it simply calls out to the existing backy command so we can still manually interact with the system even if we do not use the daemon.

• Add consul integration for backing up Flying Circus root disk images with clean snapshots (by asking fc.qemu to use fs-freeze before preparing a Ceph snapshot).

• Switch to shorter UUIDs. Existing files with old UUIDs are compatible.

• Turn the configuration format into YAML. Old files are still compatible. New configs will be generated as YAML.

• Performance: defrag all new files automatically to avoid btrfs degrading extent performance. It appears this doesn’t completely duplicate all CoW data. Will have to monitor this in the future.

2.0b1 (2014-07-07)

• Clean up docs.

• Add classifiers in setup.py.

• More or less complete rewrite expecting a copy-on-write filesystem as the target.

• Flexible backup scheduling using free-form tags.

• Compatible with Python 3.2-3.4.

• Initial open source import as provided by Daniel Kraft (D9T).