[Qemu-devel] [question] updating the base image for all clones which have been running for months

[Qemu-devel] [question] updating the base image for all clones which have been running for months

[Zhang Haoyu]

Hi, all

I used base image A to clone so many vm, 
after running for months, each vm has its own private applications and data,
which maybe different from each other.
Now, I want to install some applications for all of the clones,
what should I do?

Can I rebase image A to B which have the applications to be installed,
then change the base image to B for all clones?
I don't think it can work, the clone images maybe corrupted latter.
If the clone image's space is not enough, what will happen?
Any ideas?

My bad idea is to push the applications from center to each clone's guest-agent,
which is responsible to install the applications.

Thanks,
Zhang Haoyu

Re: [Qemu-devel] [question] updating the base image for all clones which have been running for months

[Kevin Wolf]

Am 03.11.2014 um 13:04 hat Zhang Haoyu geschrieben:
> Hi, all
> 
> I used base image A to clone so many vm, 
> after running for months, each vm has its own private applications and data,
> which maybe different from each other.
> Now, I want to install some applications for all of the clones,
> what should I do?

Install the applications on each clone separately, or use some other
method to make it available (like installing on a shared network
resource).

> Can I rebase image A to B which have the applications to be installed,
> then change the base image to B for all clones?

The problem is that rebase works on the block level, not on the file
system level. Changing the backing file won't produce a correctly
working guest, it causes file system corruption.

Kevin

Re: [Qemu-devel] [question] updating the base image for all clones which havebeen running for months

[Zhang Haoyu]

>> Hi, all
>> 
>> I used base image A to clone so many vm, 
>> after running for months, each vm has its own private applications and data,
>> which maybe different from each other.
>> Now, I want to install some applications for all of the clones,
>> what should I do?
>
>Install the applications on each clone separately, or use some other
>method to make it available (like installing on a shared network
>resource).
>
Could you detail "installing on a shared network resource"?

Thanks,
Zhang Haoyu
>> Can I rebase image A to B which have the applications to be installed,
>> then change the base image to B for all clones?
>
>The problem is that rebase works on the block level, not on the file
>system level. 
Yes, this is the point.

>Changing the backing file won't produce a correctly
>working guest, it causes file system corruption.
>
>Kevin

Re: [Qemu-devel] [question] updating the base image for all clones which havebeen running for months

[Eric Blake]

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On 11/03/2014 01:37 PM, Zhang Haoyu wrote:
>>> Hi, all
>>>
>>> I used base image A to clone so many vm, 
>>> after running for months, each vm has its own private applications and data,
>>> which maybe different from each other.
>>> Now, I want to install some applications for all of the clones,
>>> what should I do?

How would you do it for bare metal? Do the same for your guests.

>>
>> Install the applications on each clone separately, or use some other
>> method to make it available (like installing on a shared network
>> resource).
>>
> Could you detail "installing on a shared network resource"?

Set up a network file system, like NFS or gluster, install your software
on the shared file system, and then make each guest mount the shared
file system in order to use the software.  The same as you would on bare
metal.

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] [question] updating the base image for all clones which have been running for months

[Zhang Haoyu]

>>>> Hi, all
>>>>
>>>> I used base image A to clone so many vm, 
>>>> after running for months, each vm has its own private applications and data,
>>>> which maybe different from each other.
>>>> Now, I want to install some applications for all of the clones,
>>>> what should I do?
>
>How would you do it for bare metal? Do the same for your guests.
>
For bare-metal, I use manager to push the applications to each host-agent
which is running in each host, the host-agent is responsible to install the
applications.

Thanks,
Zhang Haoyu

>>>
>>> Install the applications on each clone separately, or use some other
>>> method to make it available (like installing on a shared network
>>> resource).
>>>
>> Could you detail "installing on a shared network resource"?
>
>Set up a network file system, like NFS or gluster, install your software
>on the shared file system, and then make each guest mount the shared
>file system in order to use the software.  The same as you would on bare
>metal.