Eric Blake wrote:
On 05/18/2015 01:02 PM, Jim Fehlig wrote:
> On 05/18/2015 11:35 AM, Emma Anderson wrote:
>
>> hi,
>>
>> I use xl toolstack to manage vms on a Xen machine, and also pass some
>> custom parameters when creating a vm, for example:
>>
>> xl create vm.cfg ' param="xyz" '
>>
> Documentation on create subcommand in the xl man page describes the
> 'key=value' options as
>
> key=value
> It is possible to pass key=value pairs on the command line to provide
> options as if
> they were written in the configuration file; these override whatever is
> in the
> configfile.
>
>
>> I am moving to libvirt for vm management. How I can pass those extra
>> parameters using libvirt?
>>
> I'm not aware of similar functionality in libvirt. You would need to
> customize the domXML before feeding it to 'virsh create'.
>
Qemu domains have that ability, via an XML namespace that adds
<qemu:commandline>:
http://libvirt.org/drvqemu.html#qemucommand
but no one has yet implemented that for Xen domains. If you want to add
it, the src/qemu code would be the obvious starting point to copy from.
IIUC, Emma is asking about adding/replacing entries in a config template
when creating the domain. E.g. a 'template.xl' config file might contain
memory=1024
maxmem=1024
vcpus=4
on_poweroff="destroy"
on_reboot="restart"
on_crash="destroy"
localtime=0
builder="linux"
extra='ignore_loglevel'
vfb=['type=vnc,vncunused=1']
The template can be "customized" when creating the domain by adding new
entries or overriding existing ones, using 'xl create's key=value
syntax. E.g.
xl create template.xl extra='ignore_loglevel 3 splash=silent'
name='sales-webserver' uuid='blabla'
'key' must be one of the supported config items in xl.cfg(5). The
libvirt equivalent would be something like
virsh create template.xml --cmdline 'ignore_loglevel 3 splash=silent'
--name sales-webserver --uuid blabla
but I don't think that is supported :-).
Regards,
Jim