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

[Fajar A. Nugraha]

On Thu, Jun 6, 2013 at 2:57 AM, Rory Campbell-Lange
<rory at campbell-lange.net> wrote:
>> In my case, I'd use zfs snapshot and send|receive (yes, you can use zfs
>> for root). In your case it'd probably be rsync or whatever you're happy with.
>
> Are there any files that shouldn't percolate between a normal running
> server's /etc/ and one in an lxc container?

Newer versions of Ubuntu has pretty tight lxc integration, in that if you use an
existing root on lxc, it would mostly just work. The exceptions are mostly
stuff that you'd need to take care of even on normal servers, like networking
config.

>
>> > 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?
>>
>> I'm pretty sure there were problems wiith that on some versions on lxc
>> (can't remember the exact details, sorry). A bind mount would probably
>> be safer.
>
> do you mean the exivalent of 'mount /dev/sdb1 /var/lib/lxc/' ?

mount --bind /containers /var/lib/lxc

>> > 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.
>>
>> Is there a particular requirement for that version of kernel? In
>> RHEL/Centos/Ubuntu you can often use prebuilt latest vanilla kernel
>> with only minimum change required (although the distro won't offically
>> support it, obviously).
>>
>> If you're stuck with kernel 3.2 then I'd say use zfs. The devs take extra
>> care to make sure it works well on RHEL6 (with its ancient 2.6.32 kernel),
>> and should work on all kernel from that version up to 3.9.
>
> I'm on Debian stable and I like being there for production machines
> (even though this is a backup machine). I'm not sure about the
> availability of a 3.8+ kernel on Debian.

One way to test is to use latest kernel from Debian testing, which
should be 3.9.
That is, if you're REALLY set on using btrfs

>
> I'm tempted by zfs but worried about its likely cohabitation --
> licence-wise -- over time with the kernel.

More details about this should be on zfsonlinux's list, but suffice to say that
ZoL is distributed separately from the kernel (similar to nvidia's kernel
module), and that is unlikely to change.

Looking at its current devs and contributors, personally I'm pretty
sure ZoL will still be around for quite a while.

-- 
Fajar