[Lxc-users] lxc containers as backup 'replicas'

[Rory Campbell-Lange]

Following the pretty successful tests** I've been making of using lxc
containers I'd be grateful for some advice on using lxc containers as
backp 'replicas' of running machines, to bring up in case the main host
fails.

**(I've been on the list to discuss routing problems which I've solved
temporarily by turning off kernel ethernet filtering -- still an issue
in discussion).

There are 4 parts to a running machine that I will need to replicate to
a lxc container, which I intend to do nightly. These are:

    1. etc configuration (we back config files up through etckeeper)
    2. binaries (we're happy with a dpkg -l listings here)
    3. run-time config for web apps (we back up through a file backup)
    4. database backup (backed up via log shipping)

I'd be grateful to know if it is possible to sync 1. and 3. into the
container when it is not running. In other words, to simply update the
config files in /var/lib/lxc/<container>/rootfs/etc, for example?

On another point I'd also like to know of the recommended way of using
another mount point for lxc containers and the dpkg cache. For example,
I wish to hold my containers in /dev/sdb/ mounted on /containers. Should
I symlink /var/lib/lxc/ to this mount point?

Finally I'd be grateful to learn of people's experiences with btrfs for
snapshotting and managing containers. I personally use it for my laptop
backups, but my host server is on a 3.2.0-4-amd64 kernel which is pretty
old by btrfs standards.

Rory

-- 
Rory Campbell-Lange
rory at campbell-lange.net