I understand your point, Eric and Daniel. Let me rephrase my problem statement. Please suggest me how can I address them.
I have a project environment where guest VMs are getting created and destroyed based on some (irrelevant) parameters (these guest VMs are instantiated with QEMU guest agent running and with any possible changes in that). There is a module in host which is controlling all this. I need to do following things from within that module.
1. Whenever a new guest VM is created, take (predefined) RPM packages from host to guest VM and install them.
2. Start a script in guest VM (at certain events).
3. Start a process in guest VM (at certain events).
I thought to address above issues by having a QEMU guest agent running inside guest VM which has one new command, to which I somehow pass RPMs using "virsh qemu-guest-agent ..." command.
In existing qemu-ga code, I saw some examples where they fork() and execle() some stuff. I though I can achieve [2] and [3] using the same way.
But, I was getting stuck at [1] in how to transfer files from host to guest and do something with them. I thought I should be able to transfer files using channel like socket/virtio, but was not getting the clue on how to use them.
I thought to address above issues by having a QEMU guest agent running inside guest VM which has one new command, to which I somehow pass RPMs using "virsh qemu-guest-agent ..." command.
In existing qemu-ga code, I saw some examples where they fork() and execle() some stuff. I though I can achieve [2] and [3] using the same way.
But, I was getting stuck at [1] in how to transfer files from host to guest and do something with them. I thought I should be able to transfer files using channel like socket/virtio, but was not getting the clue on how to use them.
Regards,
~Puneet
[PS: What is meant by top-post. I am using gmail and using "reply all". How can I avoid top-post?]
On Thu, Jun 12, 2014 at 8:45 PM, Eric Blake <eblake@xxxxxxxxxx> wrote:
On 06/12/2014 09:02 AM, Puneet Bakshi wrote:
[once again, please don't top-post]
Yes, that's how you set up a guest agent.
> If I add following channel in guest VM's xml file
>
> <channel type='unix'>
> <source mode='bind' path='/var/lib/libvirt/qemu/f16x86_64.agent'/>
> <target type='virtio' name='org.qemu.guest_agent.0'/>
> <alias name='channel0'/>
> <address type='virtio-serial' controller='0' bus='0' port='1'/>
> </channel>
Your FIRST task is to submit a patch to the qemu list to add yet another
>
> Would it be possible to use virtio org.qemu.guest_agent.0 for such
> communication between host and guest? If yes, how can we do it?
guest agent command that does what you want. Merely having the guest
agent does not mean you can do anything, but only that you can do what
has already been coded up in the agent interface. And looking at
http://git.qemu.org/?p=qemu.git;a=blob;f=qga/qapi-schema.json I don't
yet see a command that does what you seem to want (guest-file-open will
let you create/open a file in the guest from the host, but nothing yet
lets you create a process in the guest).
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