Re: [libvirt PATCH v2 03/81] Introduce VIR_DOMAIN_RUNNING_POSTCOPY_FAILED

This new "post-copy failed" reason for the running state will be used on the destination host when post-copy migration fails while the domain is already running there. Signed-off-by: Jiri Denemark <jdenemar(a)redhat.com&gt; --- Notes: Version 2: - documented both VIR_DOMAIN_RUNNING_POSTCOPY_FAILED and VIR_DOMAIN_PAUSED_POSTCOPY_FAILED possibilities on the destination examples/c/misc/event-test.c | 3 +++ include/libvirt/libvirt-domain.h | 2 ++ src/conf/domain_conf.c | 1 + src/libvirt-domain.c | 26 +++++++++++++++++++------- src/qemu/qemu_domain.c | 3 +++ tools/virsh-domain-event.c | 3 ++- tools/virsh-domain-monitor.c | 1 + 7 files changed, 31 insertions(+), 8 deletions(-)

diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c index e3ced700b8..b9f1d73d5a 100644 --- a/src/libvirt-domain.c +++ b/src/libvirt-domain.c @@ -9764,10 +9764,16 @@ virDomainMigrateGetMaxSpeed(virDomainPtr domain, * at most once no matter how fast it changes. On the other hand once the * guest is running on the destination host, the migration can no longer be * rolled back because none of the hosts has complete state. If this happens, - * libvirt will leave the domain paused on both hosts with - * VIR_DOMAIN_PAUSED_POSTCOPY_FAILED reason. It's up to the upper layer to - * decide what to do in such case. Because of this, libvirt will refuse to - * cancel post-copy migration via virDomainAbortJob. + * libvirt will leave the domain paused on the source host with + * VIR_DOMAIN_PAUSED_POSTCOPY_FAILED reason. The domain on the destination host + * will either remain running with VIR_DOMAIN_RUNNING_POSTCOPY_FAILED reason if + * libvirt loses control over the migration (e.g., the daemon is restarted or + * libvirt connection is broken) while QEMU is still able to continue migrating + * memory pages from the source to the destination or it will be paused with + * VIR_DOMAIN_PAUSED_POSTCOPY_FAILED if even the connection between QEMU + * processes gets broken. It's up to the upper layer to decide what to do in

+ * such case. Because of this, libvirt will refuse to cancel post-copy + * migration via virDomainAbortJob. * * The following domain life cycle events are emitted during post-copy * migration: @@ -9781,9 +9787,15 @@ virDomainMigrateGetMaxSpeed(virDomainPtr domain, * VIR_DOMAIN_EVENT_RESUMED_MIGRATED (on the destination), * VIR_DOMAIN_EVENT_STOPPED_MIGRATED (on the source) -- migration finished * successfully and the destination host holds a complete guest state. - * VIR_DOMAIN_EVENT_SUSPENDED_POSTCOPY_FAILED (on the destination) -- emitted - * when migration fails in post-copy mode and it's unclear whether any - * of the hosts has a complete guest state. + * VIR_DOMAIN_EVENT_SUSPENDED_POSTCOPY_FAILED (on the source), + * VIR_DOMAIN_EVENT_RESUMED_POSTCOPY_FAILED (on the destination) -- emitted + * when migration fails in post-copy mode from libvirt's point of view + * and it's unclear whether any of the hosts has a complete guest state. + * This happens when libvirt loses control over the migration. Virtual + * CPUs on the destination are still running. + * VIR_DOMAIN_EVENT_SUSPENDED_POSTCOPY_FAILED (on the destination) -- QEMU is + * not able to keep migration running in post-copy mode (i.e., its + * connection is broken) and libvirt stops virtual CPUs on the destination.

* * The progress of a post-copy migration can be monitored normally using * virDomainGetJobStats on the source host. Fetching statistics of a completed