On Wed, Nov 25, 2009 at 04:40:07PM +0100, Paolo Bonzini wrote:
> This adds a new flag, VIR_MIGRATE_PAUSED, that mandates pausing
> the migrated VM before starting it.
>
> * include/libvirt/libvirt.h.in (virDomainMigrateFlags): Add
> VIR_MIGRATE_PAUSED.
> * src/qemu/qemu_driver.c (qemudDomainMigrateFinish2): Handle
> VIR_MIGRATE_PAUSED.
> * tools/virsh.c (opts_migrate): Add --suspend.
> (cmdMigrate): Handle it.
> * tools/virsh.pod (migrate): Document it.
> ---
> The complicated part of the patch is simply this with diff -b:
>
> @@ -7320,6 +7320,7 @@ qemudDomainMigrateFinish2 (virConnectPtr dconn,
> qemuDomainObjPrivatePtr priv = vm->privateData;
> dom = virGetDomain (dconn, vm->def->name, vm->def->uuid);
>
> + if (!(flags & VIR_MIGRATE_PAUSED)) {
> /* run 'cont' on the destination, which allows migration on
> qemu
> * >= 0.10.6 to work properly. This isn't strictly necessary
> on
> * older qemu's, but it also doesn't hurt anything there
> @@ -7335,9 +7336,17 @@ qemudDomainMigrateFinish2 (virConnectPtr dconn,
> qemuDomainObjExitMonitorWithDriver(driver, vm);
>
> vm->state = VIR_DOMAIN_RUNNING;
> + }
>
> include/libvirt/libvirt.h.in | 1 +
> src/libvirt.c | 1 +
> src/qemu/qemu_driver.c | 33 +++++++++++++++++++++------------
> tools/virsh.c | 5 ++++-
> tools/virsh.pod | 7 ++++---
> 5 files changed, 31 insertions(+), 16 deletions(-)
>
> diff --git a/include/libvirt/libvirt.h.in b/include/libvirt/libvirt.h.in
> index 5bc7694..0488cbf 100644
> --- a/include/libvirt/libvirt.h.in
> +++ b/include/libvirt/libvirt.h.in
> @@ -341,6 +341,7 @@ typedef enum {
> VIR_MIGRATE_TUNNELLED = (1 << 2), /* tunnel migration data over
> libvirtd connection */
> VIR_MIGRATE_PERSIST_DEST = (1 << 3), /* persist the VM on the
> destination */
> VIR_MIGRATE_UNDEFINE_SOURCE = (1 << 4), /* undefine the VM on the
> source */
> + VIR_MIGRATE_PAUSED = (1 << 5), /* pause on remote side */
> } virDomainMigrateFlags;
>
> /* Domain migration. */
> diff --git a/src/libvirt.c b/src/libvirt.c
> index 05e45f3..2ced604 100644
> --- a/src/libvirt.c
> +++ b/src/libvirt.c
> @@ -3179,6 +3179,7 @@ virDomainMigrateDirect (virDomainPtr domain,
> * on the destination host.
> * VIR_MIGRATE_UNDEFINE_SOURCE If the migration is successful, undefine the
> * domain on the source host.
> + * VIR_MIGRATE_PAUSED Leave the domain suspended on the remote side.
> *
> * VIR_MIGRATE_TUNNELLED requires that VIR_MIGRATE_PEER2PEER be set.
> * Applications using the VIR_MIGRATE_PEER2PEER flag will probably
> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
> index 44cec6c..4d20fb7 100644
> --- a/src/qemu/qemu_driver.c
> +++ b/src/qemu/qemu_driver.c
> @@ -7320,24 +7320,33 @@ qemudDomainMigrateFinish2 (virConnectPtr dconn,
> qemuDomainObjPrivatePtr priv = vm->privateData;
> dom = virGetDomain (dconn, vm->def->name, vm->def->uuid);
>
> - /* run 'cont' on the destination, which allows migration on qemu
> - * >= 0.10.6 to work properly. This isn't strictly necessary on
> - * older qemu's, but it also doesn't hurt anything there
> - */
> - qemuDomainObjEnterMonitorWithDriver(driver, vm);
> - if (qemuMonitorStartCPUs(priv->mon, dconn) < 0) {
> - if (virGetLastError() == NULL)
> - qemudReportError(dconn, NULL, NULL, VIR_ERR_INTERNAL_ERROR,
> - "%s", _("resume operation failed"));
> + if (!(flags & VIR_MIGRATE_PAUSED)) {
> + /* run 'cont' on the destination, which allows migration on qemu
> + * >= 0.10.6 to work properly. This isn't strictly necessary on
> + * older qemu's, but it also doesn't hurt anything there
> + */
> + qemuDomainObjEnterMonitorWithDriver(driver, vm);
> + if (qemuMonitorStartCPUs(priv->mon, dconn) < 0) {
> + if (virGetLastError() == NULL)
> + qemudReportError(dconn, NULL, NULL,
> VIR_ERR_INTERNAL_ERROR,
> + "%s", _("resume operation failed"));
> + qemuDomainObjExitMonitorWithDriver(driver, vm);
> + goto endjob;
> + }
> qemuDomainObjExitMonitorWithDriver(driver, vm);
> - goto endjob;
> +
> + vm->state = VIR_DOMAIN_RUNNING;
> }
> - qemuDomainObjExitMonitorWithDriver(driver, vm);
>
> - vm->state = VIR_DOMAIN_RUNNING;
> event = virDomainEventNewFromObj(vm,
> VIR_DOMAIN_EVENT_RESUMED,
> VIR_DOMAIN_EVENT_RESUMED_MIGRATED);
> + if (vm->state == VIR_DOMAIN_PAUSED) {
> + qemuDomainEventQueue(driver, event);
> + event = virDomainEventNewFromObj(vm,
> + VIR_DOMAIN_EVENT_SUSPENDED,
> +
> VIR_DOMAIN_EVENT_SUSPENDED_PAUSED);
> + }
> virDomainSaveStatus(dconn, driver->stateDir, vm);
> } else {
> qemudShutdownVMDaemon (dconn, driver, vm);
> diff --git a/tools/virsh.c b/tools/virsh.c
> index 9faac35..9871b4b 100644
> --- a/tools/virsh.c
> +++ b/tools/virsh.c
> @@ -2478,6 +2478,7 @@ static const vshCmdOptDef opts_migrate[] = {
> {"tunnelled", VSH_OT_BOOL, 0, gettext_noop("tunnelled migration")},
> {"persistent", VSH_OT_BOOL, 0, gettext_noop("persist VM on
> destination")},
> {"undefinesource", VSH_OT_BOOL, 0, gettext_noop("undefine VM on
> source")},
> + {"suspend", VSH_OT_BOOL, 0, gettext_noop("do not restart the domain on
> the destination host")},
> {"domain", VSH_OT_DATA, VSH_OFLAG_REQ, gettext_noop("domain name, id or
> uuid")},
> {"desturi", VSH_OT_DATA, VSH_OFLAG_REQ, gettext_noop("connection URI of
> the destination host")},
> {"migrateuri", VSH_OT_DATA, 0, gettext_noop("migration URI, usually can
> be omitted")},
> @@ -2519,10 +2520,12 @@ cmdMigrate (vshControl *ctl, const vshCmd *cmd)
>
> if (vshCommandOptBool (cmd, "persistent"))
> flags |= VIR_MIGRATE_PERSIST_DEST;
> -
> if (vshCommandOptBool (cmd, "undefinesource"))
> flags |= VIR_MIGRATE_UNDEFINE_SOURCE;
>
> + if (vshCommandOptBool (cmd, "suspend"))
> + flags |= VIR_MIGRATE_PAUSED;
> +
> if ((flags & VIR_MIGRATE_PEER2PEER) ||
> vshCommandOptBool (cmd, "direct")) {
> /* For peer2peer migration or direct migration we only expect one URI
> diff --git a/tools/virsh.pod b/tools/virsh.pod
> index 6ff0151..3830464 100644
> --- a/tools/virsh.pod
> +++ b/tools/virsh.pod
> @@ -302,10 +302,11 @@ except that it does some error checking.
> The editor used can be supplied by the C<$EDITOR> environment
> variable, or if that is not defined defaults to C<vi>.
>
> -=item B<migrate> optional I<--live> I<domain-id> I<desturi> I<migrateuri>
> +=item B<migrate> optional I<--live> I<--suspend> I<domain-id> I<desturi>
> I<migrateuri>
>
> -Migrate domain to another host. Add --live for live migration. The
> I<desturi>
> -is the connection URI of the destination host, and I<migrateuri> is the
> +Migrate domain to another host. Add --live for live migration; --suspend
> +leaves the domain paused on the destination host. The I<desturi> is the
> +connection URI of the destination host, and I<migrateuri> is the
> migration URI, which usually can be omitted.
>
> =item B<reboot> I<domain-id>
ACK, though one thing I notice is that the QEMU driver isn't validating
the flags passed in
For example Xen does
if (flags & VIR_MIGRATE_UNDEFINE_SOURCE) {
undefined_source = 1;
flags &= ~VIR_MIGRATE_UNDEFINE_SOURCE;
}
/* Ignore the persist_dest flag here */
if (flags & VIR_MIGRATE_PERSIST_DEST)
flags &= ~VIR_MIGRATE_PERSIST_DEST;
/* XXX we could easily do tunnelled & peer2peer migration too
if we want to. support these... */
if (flags != 0) {
virXendError (conn, VIR_ERR_NO_SUPPORT,
"%s", _("xenDaemonDomainMigrate: unsupported flag"));
return -1;
}
This means if you tried to use this new '--suspend' feature with Xen you'd
get a nice error. If you used it with an old QEMU it'd silently complete
and do nothing. We can't do much about this now, but I think it is worth
adding in such a check, so if we add more migration flags later we wil be
validating them
ACK to this patch anyway
Daniel
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