zhang bo b6fcd7ba06 util: don't fail if no PortData is found while getting migrateData
Introduced by f6a2f97e

Problem Description:
After multiple times of migrating a domain, which has an ovs interface with no portData set,
with non-shared disk, nbd ports got overflowed.

The steps to reproduce the problem:
1 define and start a domain with its network configured as:
    <interface type='bridge'>
          <source bridge='br0'/>
          <virtualport type='openvswitch'>
          </virtualport>
          <model type='virtio'/>
          <driver name='vhost' queues='4'/>
    </interface>
2 do not set the network's portData.
3 migrate(ToURI2) it with flag 91(1011011), which means:
  VIR_MIGRATE_LIVE
  VIR_MIGRATE_PEER2PEER
  VIR_MIGRATE_PERSIST_DEST
  VIR_MIGRATE_UNDEFINE_SOURCE
  VIR_MIGRATE_NON_SHARED_DISK
4 migrate success, but we got an error log in libvirtd.log:
  error : virCommandWait:2423 : internal error: Child process (ovs-vsctl --timeout=5 get Interface
  vnet1 external_ids:PortData) unexpected exit status 1: ovs-vsctl: no key "PortData" in Interface
  record "vnet1" column external_ids
5 migrate it back, migrate it , migrate it back, .......
6 nbd port got overflowed.

The reasons for the problem is :
1 virNetDevOpenvswitchGetMigrateData() takes it as wrong if no portData is available for  the ovs
 interface of a domain. (We think it's not appropriate, as portData is just OPTIONAL)
2 in func qemuMigrationBakeCookie(), it fails in qemuMigrationCookieAddNetwork(), and returns with -1.
 qemuMigrationCookieAddNBD() is not called thereafter, and mig->nbd is still NULL.
3 However, qemuMigrationRun() just *WARN* if qemuMigrationBakeCookie() fails, migration still successes.
 cookie is NULL, it's not baked on the src side.
4 On the destination side, it would alloc a port first and then free the nbd port in COOKIE.
 But the cookie is NULL due to qemuMigrationCookieAddNetwork() failure at src side. thus the nbd port
 is not freed.

In this patch, we add "--if-exists" option to make ovs-vsctl not raise error if there's no portData available.
Further more, because portData may be NULL in the cookie at the dest side, check it before setting portData.

Signed-off-by: Zhou Yimin <zhouyimin@huawei.com>
Signed-off-by: Zhang Bo <oscar.zhangbo@huawei.com>
(cherry picked from commit 25df57db73adc3e610193ee1fcdd202c47ba471d)
2015-04-28 11:06:41 -04:00
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2014-06-26 14:32:35 +01:00

         LibVirt : simple API for virtualization

  Libvirt is a C toolkit to interact with the virtualization capabilities
of recent versions of Linux (and other OSes). It is free software
available under the GNU Lesser General Public License. Virtualization of
the Linux Operating System means the ability to run multiple instances of
Operating Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms if needed.

Daniel Veillard <veillard@redhat.com>
Description
Libvirt provides a portable, long term stable C API for managing the virtualization technologies provided by many operating systems. It includes support for QEMU, KVM, Xen, LXC, bhyve, Virtuozzo, VMware vCenter and ESX, VMware Desktop, Hyper-V, VirtualBox and the POWER Hypervisor.
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