Re: [Xen-users] how to start VMs in a particular order

[lee <lee@xxxxxxxxxxxxxxx>]

"J. Roeleveld" <joost@xxxxxxxxxxxx> writes:

> On Saturday, June 28, 2014 08:25:11 AM lee wrote:
>> "J. Roeleveld" <joost@xxxxxxxxxxxx> writes:
>> > On Thursday, June 26, 2014 06:19:30 PM lee wrote:
>> >> Since dom0 crashes once every 24 hours, it would be nice if I could at
>> >> least get the machine rebooted without more intervention than having to
>> >> press the reset button ...
>> > 
>> > I would fix this with a higher priority, to be honest.
>> 
>> Yes, if I could ...
>> 
>> So far, I might have made some progress on that by removing a package
>> that checks the status of the RAID volumes.  It's too early to tell for
>> sure; at least the server hasn't crashed since.
>
> Interesting. Maybe check on a Debian mailing list to see what that package 
> might be doing to cause a crash?

Apparently it's using arcconf to query the status of the
volumes/controller.  Last crash, I got a message on the console saying
that arcconf appeared to be hanging for 120 seconds, and the regularity
of the crashes was suspicious.  The software is ancient, so it's
possible that it causes problems with somewhat recent kernels :(

>> On Debian, /etc/init.d/xendomains seems to be what brings up the domains
>> automatically.  It would be a good place to add a timer or to add checks
>> for services.
>
> That script is part of Xen, not just Debian. I have the same file in Gentoo.

Hm, is it still there when systemd is used?

>> So when you're careful, you can specify the order in which VMs are
>> brought up (at least when using Debians' script) --- but is it a granted
>> feature that the names always appear in any particular order?  It looks
>> more like a side effect.
>
> It is how the shell, by default, orders files when enumerating wild-cards.
> This can be relied upon.

With any shell that might be used?

>> Anyway, I think I'll modify the script so that the domains are brought
>> up in a particular order with fixed delays as needed.  That seems the
>> most simple and efficient way to do it.
>
> I did something similar.
> I have the following directories:
>
> ****
> # ls /etc/xen/auto/
> disabled  stage1  stage2  stage3  stage4  stage5
> ****
>
> I then have duplicates for the xendomains script, with a few changes, that 
> starts the domains in the relevant stage folder.
> Currently, I check that the domains in the stage-folder are started 
> successfully before the next one is started.

That's a good idea; I'll do that likewise.


-- 
Knowledge is volatile and fluid.  Software is power.

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxx
http://lists.xen.org/xen-users