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

On Mon, Dec 8, 2014 at 7:31 PM, Matthias Gatto <matthias.gatto(a)outscale.com&gt; 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