Re: [vserver] Fedora as host?

From: Ed W <>
Date: Wed 10 Oct 2012 - 18:35:47 BST
Message-ID: <>

On 06/09/2012 09:33, Tor Rune Skoglund wrote:

> Personally, I am used to Gentoo, and the vserver system works
> perfectly. However, in our use case, we might need to avoid a Gentoo
> due the need of quicker updates than what is possible by a source code
> based distro like Gentoo.
> Any comments appreciated.

I use Gentoo on a whole bunch of vservers. My solution is:

- extensive use of custom "profiles". eg I have
- template vservers which are kept mostly up to date. Use these as rsync
build targets to create new images from
- nearly all vservers are close to identical (got a few 32bit wierd
ones, but that's all).
- set portage to create binary packages (and mount the shared package
dir on guests)
- mount the shared package directory differently on
host/guest/wierd-guests. This means you can mainly keep all binary
packages for a given large class of systems.
- update using "emerge -uvDkp --newuse world". The --newuse ensures
that a binary package is rebuilt if necessary due to changed USE flags
from the ones used in the binary package, -k uses binary packages if
they are available (-K to mandate only binary packages, no builds allowed)

Mainly I can then update the template servers, and updating the rest is
then 90% from binary packages. I have only some wierdness with eg,
mysql in that I build the whole server for two instances, but minimal
client tools for everything else - probably I should do some magic in
the package location, but mainly I just order the updates to reduce
rebuilds of that package.

It helps to sync things like PHP flags across servers to reduce rebuilds
(or get clever with binary package locations). eg I might not need
"spell" on every instance, but it saves rebuilds just to keep the binary
instances the same (security gurus are not inhibited from making their
own choice here though)

Additionally I mount my data separately from the OS (I use
/vserver/images/ and /vserver/shared/), and this makes it simple to
snapshot the OS, and fire it up pointing at the live data (mount the
shared data in both images - obviously be careful that this is valid, eg
don't mount a mysql db twice, but for example www files or mail spools
are often fine to be served from two servers at once)

This process above could be used to rebuild a test image first before
you update the live image, and in fact if you needed near instant
switching then simply update the test image, test it, then stop both and
switch out the image directories and restart (takes 5 seconds or so?).
You could even use IP switching or iptables to have basically instant
swapouts if a few seconds is too long? (eg fire up a pool of vservers,
each mounting shared data files and use some load balancer to take out
machines individually as you update them - relatively easy under vserver)

Finally: Daniel very kindly added some features to "vsomething" command
and you can use --mark on multiple marks. I mark up my vservers based
on their class (more than one mark per server), eg www, test, live,
mysql, dont-break-me-be-really-careful. Then I can use vsomething to
run emerge on all servers which meet certain criteria, eg every dev
server running, except the ones marked dont-break-me. Very handy

Good luck

Ed W
Received on Wed Oct 10 18:35:59 2012

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