[virt-tools-list] Including standard stanzas in new libvirt domain definitions

[Sorrillo, Lawrence]

By others I mean anyone who wants to include any qemu supported custom stanzas automatically in their libvirt XML domain definitions.

I can image different sites might find something like this useful and am a bit surprised this isn't already included.

Recently I discovered, 

	virsh domxml-from-native qemu-argv vm.args > vm.xml

which is wonderful because it allow us to force livbirt to describe features that qemu knows about but which libvirt doesn't natively know about. 
This is desirable for some.

But in general I can imagine the ability to pass custom hypervisor specific stanzas to libvirt for automatically inclusion in VM domain definitions is something that
can be useful as virtualization develops.

I am experimenting with virt-xml but I would rather the stanza included at first creation of the domain XML definition. 
What if I had another lay of abstraction above libivrt, like Openstack?  This is where automating custom VM definitions become helpful.

~Lawremce



-----Original Message---
From: Cole Robinson [mailto:crobinso at redhat.com] 
Sent: Sunday, September 13, 2015 1:57 PM
To: Sorrillo, Lawrence; 'virt-tools-list at redhat.com'
Subject: Re: [virt-tools-list] Including standard stanzas in new libvirt domain definitions

Do you mean 'others' in general or something specific to your setup? I'd
probably need more details about what you are trying to accomplish.

You can simplify adding the device to an existing VM using the virt-xml tool,
it shouldn't be hard to come up with a one liner. You could tell users to run
that manually for each VM you want. Or you could build a script that iterates
over every VM on the system and attached that filesystem if it doesn't already
exist.

But to do it in an automated fashion for every new VM... maybe using libvirt
hooks or some crazy inotify watch on /etc/libvirt but that's getting pretty
intense.

- Cole

On 09/13/2015 01:33 PM, Sorrillo, Lawrence wrote:
> Cole,
> 
> Do you have any suggestions about where I might start to do this in a way that perhaps others might use it?
> 
> ~Lawrence
> 
> -----Original Message-----
> From: Cole Robinson [mailto:crobinso at redhat.com] 
> Sent: Sunday, September 13, 2015 1:17 PM
> To: Sorrillo, Lawrence; 'virt-tools-list at redhat.com'
> Subject: Re: [virt-tools-list] Including standard stanzas in new libvirt domain definitions
> 
> On 09/13/2015 11:54 AM, Sorrillo, Lawrence wrote:
>> I had to use the upstream qemu to get the filesystem passthrough to be enabled.
>>
>> I have another question:  I would like to always  include and automate  a standard stanza in newly created libvirt  XML domain definition of a VM.
>> For example, 
>>
>> <filesystem type='mount' accessmode='passthrough'>
>>    <source dir='/var/tmp/shareme1'/>
>>    <target dir='hostshare1'/>
>>    <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
>> </filesystem>
>>
>> Is there a way, a qemu configuration or a libvirt config, to automate  including this stanza in all newly created VMs?
>>
> 
> No there isn't any option for that, you'd probably need to come up with your
> own solution to make it work.
> 
> - Cole
> 
>>
>> -----Original Message-----
>> From: Cole Robinson [mailto:crobinso at redhat.com] 
>> Sent: Thursday, September 03, 2015 1:36 PM
>> To: Sorrillo, Lawrence; 'virt-tools-list at redhat.com'
>> Subject: Re: [virt-tools-list] "Grey-out" Filesystem add hardware option in virt-manager in RHEL7.1 - kernel 3.10.0-229.11.1.el7.x86_64
>>
>> On 09/02/2015 01:53 PM, Sorrillo, Lawrence wrote:
>>> Hello,
>>>
>>>  
>>>
>>> I was wondering about virt-manager support for the file-sharing option between
>>> host and guest in RedHat, CentOS and Fedora.
>>>
>>>  
>>>
>>> This appears to be grey out and a complaint about the inability of the
>>> installed combination of
>>>
>>> libvirt and qemu to support this option is displayed. The link below shows the
>>> virt-manager screen 
>>>
>>> WITHOUT the grey-out filesystem option.
>>>
>>>  
>>>
>>> http://www.linux-kvm.org/page/9p_virtio
>>>
>>>  
>>>
>>> For redhat based linuxes though this appears to be always greyed out in stock
>>> builds(even without 9p
>>>
>>> and even when Qemu supports the file sharing option). Why is this?
>>>
>>>  
>>>
>>> [root at xxx tmp]# qemu-kvm --version
>>>
>>> *QEMU emulator version 1.5.3 (qemu-kvm-1.5.3-86.el7_1.5), Copyright (c)
>>> 2003-2008 Fabrice Bellard*
>>>
>>> [root at xxx tmp]# qemu-kvm --help | grep fsdev
>>>
>>> *-fsdev
>>> fsdriver,id=id[,path=path,][security_model={mapped-xattr|mapped-file|passthrough|none}]*
>>>
>>> [root at xxx tmp]#  tmp]#
>>>
>>> root at xxx   tmp]#
>>>
>>> [root at xxx    tmp]# rpm -qa | grep libvirt-1.2.8
>>>
>>> *libvirt-1.2.8-16.el7_1.3.x86_64*
>>>
>>> [root at xxx  tmp]#
>>
>> It's likely disabled/greyed-out on RHEL because on RHEL Red Hat explicitly
>> doesn't support filesystem passthrough for various maintenance and business
>> reasons. I think even if you attached the XML to your libvirt config, qemu
>> would fail to start because it's compiled out, but I haven't verified.
>>
>> - Cole
>>
>>
> 
>