[libvirt] [PATCH 0/9] qemu: Add quorum support to libvirt

[Matthias Gatto]

On Mon, Dec 8, 2014 at 7:31 PM, Matthias Gatto
<matthias.gatto at outscale.com> wrote:
> The purpose of these patches is to introduce quorum for libvirt
> I've try to follow this proposal:
> http://www.redhat.com/archives/libvir-list/2014-May/msg00533.html
>
> This feature ask for 6 task:
>
> 1) Allow a _virStorageSource
> to contain more than one backing store.
>
> Therefore we have to treat the field virStorageSourcePtr backingStores
> as an array instead of a pointer.
> But doing that, most of the backingStore field would be an array contening
> only one element.
> So I've decide to allocate the array only if there is more than 1
> backing store in a _virStorageSource.
> Because all the actual libvirt code use the backingStore field
> as a pointer and we needs want to change that, I've decide to encapsulate
> the backingStore field to simplifie the array manipulation.
>
> 2) Add the missing field a quorum need in _virStorageSource and
> the VIR_STORAGE_TYPE_QUORUM and VIR_STORAGE_FILE_QUORUM in
> their respectives enums.
>
> 3) Parse and format the xml
> Because a quorum allows to have more than one backing store at the same level
> we need to change virDomainDiskDefFormat and virDomainDiskDefParseXML
> to call virDomainDiskBackingStoreFormat and virDomainDiskBackingStoreParse
> in a loop.
> virDomainDiskBackingStoreFormat and virDomainDiskBackingStoreParse can
> call themself recursively in a loop because a quorum can contain another
> quorum
>
> 4) Add nodename
> We need to add nodename support in _virStorageSource because qemu
> use them for their child.
>
> 5) Build qemu string
> As for the xml, we have to call the function which create quorum recursively.
> But this task have the problem explained here:
> http://www.redhat.com/archives/libvir-list/2014-October/msg00529.html
> The _virStorageSource missing some informations that can be passed to
> a child, and therefore this version of quorum is incomplet.
>
> 6) Allow to hotplug/change a disk in a quorum
> This part is not present in these patches because for this task
> we have to use blockdev-add, and currently libvirt use
> device_add for hotpluging that doesn't allow to hotplug quorum childs.
>
> There is 3 way to handle this problem:
>       1) create a virDomainBlockDevAdd function in libvirt witch call
>       blockdev-add.
>
>       2) use blockdev-add instead of device_add in qemuMonitorJSONAddDevice
>
>       3) write a hack which uses blockdev-add when only attaching quorum
>       (but i'm pretty sure this solution is not the good one)
>
> Matthias Gatto (9):
>   virstoragefile: Add virStorageSourceGetBackingStore
>   virstoragefile: Always use virStorageSourceGetBackingStore to get
>     backing store
>   virstoragefile: Add virStorageSourceSetBackingStore
>   virstoragefile: Always use virStorageSourceSetBackingStore to set
>     backing store
>   virstoragefile: Treat backingStore as a pointer or an array
>   virstoragefile: Add quorum in virstoragefile
>   domain_conf: Read and Write quorum config
>   qemu: Add quorum support in qemuBuildDriveDevStr
>   virstoragefile: Add node-name
>
>  src/conf/domain_conf.c                | 193 ++++++++++++++++++++++++++--------
>  src/conf/storage_conf.c               |   7 +-
>  src/libvirt_private.syms              |   3 +
>  src/qemu/qemu_cgroup.c                |   4 +-
>  src/qemu/qemu_command.c               | 114 ++++++++++++++++++++
>  src/qemu/qemu_domain.c                |   3 +-
>  src/qemu/qemu_driver.c                |  20 ++--
>  src/security/security_dac.c           |   2 +-
>  src/security/security_selinux.c       |   4 +-
>  src/security/virt-aa-helper.c         |   2 +-
>  src/storage/storage_backend.c         |  12 +--
>  src/storage/storage_backend_fs.c      |  12 +--
>  src/storage/storage_backend_logical.c |   4 +-
>  src/storage/storage_driver.c          |   2 +-
>  src/util/virstoragefile.c             | 136 +++++++++++++++++++++---
>  src/util/virstoragefile.h             |  12 +++
>  tests/virstoragetest.c                |  18 ++--
>  17 files changed, 445 insertions(+), 103 deletions(-)
>
> --
> 1.8.3.1
>

ping