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Re: Problem with KVM version in Buildbot?


On Mon, Oct 20, 2014 at 7:12 AM, Kristian Nielsen
<knielsen@xxxxxxxxxxxxxxx> wrote:
> Otto Kekäläinen writes:
>> There is no need for this image to be so big. The OS is maybe that 3.1
>> GB and the MariaDB build output is about 3 GB, so something like 9 GB
>> disk size should be well enough by a fair margin.
> Right.
> On the other hand, there is a lot of work involved in re-doing the VM images
> in case of too-small image, so I can understand Daniel's reasons for making
> the images "large enough". This is just the maximum size, the actual size will
> be no bigger than what is actually used.
> However, with a large max size, we still need to disable the ramdisk
> usage. Because in case a lot of space is used, this can cause failures in
> other, unrelated builds due to disk full.
> I don't know that the ramdisk optimisation is that important anyway, so it
> seems reasonable to just disable it here.
>> + qemu-img create -b /kvm/vms/vm-centos7_0-x86_64-build.qcow2 -f qcow2 /dev/shm/vm-tmp-2302.qcow2
>> qemu-img: '' uses a qcow2 feature which is not supported by this qemu version: QCOW version 3
>> qemu-img: Could not open '/kvm/vms/vm-centos7_0-x86_64-build.qcow2'
>> Failed to clone base image, aborting
> For now, I updated the Buildbot config to not use the terrier buildslave for
> this builder. If any more images are made with the newer file version, the
> associated builders need to be similarly disabled, using this option:
>    slaves=kvm11_slaves

I think it was just the CentOS7 VMs that were created such that they
aren't compatible with the older qcow2 format. When I made the
opensuse VMs, for example, I made sure they used the old qcow2 format.
That said, I think we really need to rebuild terrier, to get it
up-to-date, install a larger hard disk, and generally get it more in
step with bb01 and bb02, but that's a different discussion.

>> Also, another issue related to VM images. Our old images were created with
>> rather small disk size. I noticed that some new images are created much
>> larger, for example:
>> I will try to fix the config to not use ramdisk for existing images that have
>> too large virtual size. But it is something to keep in mind for the future.
> So now I added an option ramdisk=True|False to getDebBuilder() and similar
> functions. And I checked all images, and added ramdisk=False for all those
> builders that I found used some of the images with large maximum size.
> Any further image made with large max size should then also use the
> ramdisk=False option.
> An alternative method to having big VM max size is to do like getFullTest()
> does. It adds an extra blank disk image that is not put in ramdisk:
>   args = args + ["--kvm=-hdb", "--kvm=vm-blank-20G.qcow2"]
> and then mounts and uses it inside the VM.
> But again, if the ramdisk optimisation is not needed on the newer/better
> buildbot machines, there might be little need for this extra complexity.

Thanks! This solution works for me.

Daniel Bartholomew, MariaDB Release Manager
MariaDB | http://mariadb.com