[Linux-ha-dev] new stonith external plugin

[Serge Dubrouski]

On 12/21/06, Andrew Beekhof <beekhof at gmail.com> wrote:
> On 12/21/06, Serge Dubrouski <sergeyfd at gmail.com> wrote:
> > On 12/21/06, Andrew Beekhof <beekhof at gmail.com> wrote:
> > > On 12/21/06, Serge Dubrouski <sergeyfd at gmail.com> wrote:
> > > > On 12/21/06, Andrew Beekhof <beekhof at gmail.com> wrote:
> > > > > On 12/21/06, Serge Dubrouski <sergeyfd at gmail.com> wrote:
> > > > > > Attached is xen0 external stonith plugin (slightly changes ssh plugin)
> > > > > > that can use Xen Dom0 as a stonith device.
> > > > > >
> > > > > > Requirements:
> > > > > >
> > > > > > 1. hostlist parameter configured in cib.xml in a format
> > > > > > node_name:dom0_hostname:configfile_for_dumU
> > > > > >
> > > > > > 2. node_name must be the same as DomU name in Xen.
> > > > > >
> > > > > > 3. xm command has to be available through PATH variable on Dom0
> > > > > >
> > > > > > 4. ssh access without password from cluster nodes to Xen  Dom0.
> > > > > >
> > > > > > When this plugin receives "reset" command it tries to kill DomU with
> > > > > > "xm destroy" and then restart it with "xm create". On and Off commands
> > > > > > aren't supported. But can be easily added if required.
> > > > >
> > > > > i think that would be a good idea
> > > >
> > > > I'll add it.
> > > >
> > > > >
> > > > > > Of course this plugin isn't a good solution for production but can be
> > > > > > used is a testing environment.
> > > > >
> > > > >
> > > > > a nice addition would be for the RA to detect the list of DomU's at
> > > > > startup (and redetect during status or some other recurring action).
> > > > > that would make stonith configuration for clusters of virtual nodes a
> > > > > no-brainer.
> > > >
> > > > I'm not sure that it would work or I don't really get it. The idea
> > > > here is to have a cluster out of virtual nodes. For example on one Xen
> > > > server I configure node1 and on another node2. Heartbeat on those
> > > > nodes doesn't know that it's running on virtual nodes under Xen but
> > > > with this new plugin properly configured it'll be able to kill a
> > > > failed node if necessary. In this configuration Xen RA isn't used at
> > > > all.
> > >
> > > right but we know and as a result we'd add this resource with a list of Dom0s.
> > >
> > > that is enough information for the resource to use "xm list" and
> > > populate the hostlist.
> > > so now any cluster member that is also a DomU can now be fenced.
> >
> > That a nice idea! I'll work on it. Though it'll complicate the script
> > little bit and I'd like to switch to something more intelligent than
> > shell. Probably perl.
>
> not a bad choice... it'd certainly make parsing the output from the xm
> commands easier

Unfortunately there is a problem. I can't find any other way, besides
a user configuring it manually in cib.xml, to find out a name of
config file for DomU. Without that config file name I'm not able to
create a domain. So either user have to set that name in cib.xml or to
put all DomU config files into some default place.