Re: [libvirt] [PATCH 2/2] qemu: don't update cpu unconditionally for migratable flag
On Thu, Sep 21, 2017 at 16:39:39 +0300, Nikolay Shirokovskiy wrote:
Imagine if we use 'virsh dumpxml --migratable' for offline
domain
to get config to tweak before migration. Currenly cpu section will
be expanded, host-cpu mode turns into custom and migration fails
because of ABI check.
Looks like ABI check does not make much sence for offline migration
but we don't want host-cpu mode to turn into custom in the first place.
Using --migratable is reasonable in this case because this flags
makes changes for inactive configs too like removing automatically
added parts that old versions can not handle.
I suggest not to update cpu for inactive configs. This appoach is
coherent with the way migration works for inactive configs in case
it is not specified externally to migration: function qemuMigrationCookieXMLFormat
don't expand cpu too.
Adding flag for active configs is useless because qemuDomainFormatXML
will clear it in this case.
Not anymore, see commit v3.7.0-151-g06f75ff2cb.
...
diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index d9dff93..3223554 100644
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -6993,9 +6993,6 @@ static char
if (qemuDomainUpdateCurrentMemorySize(driver, vm) < 0)
goto cleanup;
- if ((flags & VIR_DOMAIN_XML_MIGRATABLE))
- flags |= VIR_DOMAIN_XML_UPDATE_CPU;
-
ret = qemuDomainFormatXML(driver, vm, flags);
cleanup:
This area of code changed recently and it looks like the following now:
if ((flags & VIR_DOMAIN_XML_MIGRATABLE))
flags |= QEMU_DOMAIN_FORMAT_LIVE_FLAGS;
/* The CPU is already updated in the domain's live definition, we need to
* ignore the VIR_DOMAIN_XML_UPDATE_CPU flag.
*/
if (virDomainObjIsActive(vm) &&
!(flags & VIR_DOMAIN_DEF_FORMAT_INACTIVE))
flags &= ~VIR_DOMAIN_XML_UPDATE_CPU;
But even before the changes, the two lines you are removing were
if ((flags & VIR_DOMAIN_XML_MIGRATABLE))
flags |= QEMU_DOMAIN_FORMAT_LIVE_FLAGS;
since commit v0.10.2-133-g28f8dfdccc, i.e., for the last 5 years. I
guess you have some local changes applied to the libvirt tree.
Jirka