[PATCH] virnetdevopenvswitch: Create OVS ports as transient
Since OVS keeps desired state in a DB, upon sudden crash of the host we may leave a port behind. There's no problem on VM shutdown or NIC hotunplug as we call corresponding del-port function (virNetDevOpenvswitchRemovePort()). But if the host suddenly crashes we won't ever do that. What happens next, is when OVS starts it finds desired state in its DB and creates a stale port. OVS added support for transient ports in v2.5.0 (Feb 2016) and since its v2.9.0 it even installs a systemd service (ovs-delete-transient-ports) that automatically deletes transient ports on system startup. If we mark a port as transient then OVS won't restore its state on restart after crash. This change may render "--may-exist" argument redundant, but I'm not sure about all the implications if it was removed. Let's keep it for now. Resolves: https://gitlab.com/libvirt/libvirt/-/issues/615 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/util/virnetdevopenvswitch.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c index f1765ae1c8..e23f4c83b6 100644 --- a/src/util/virnetdevopenvswitch.c +++ b/src/util/virnetdevopenvswitch.c @@ -164,7 +164,9 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname, cmd = virNetDevOpenvswitchCreateCmd(&errbuf); virCommandAddArgList(cmd, "--", "--may-exist", - "add-port", brname, ifname, NULL); + "add-port", brname, ifname, + "--", "set", "Port", ifname, "other_config:transient=true", + NULL); virNetDevOpenvswitchConstructVlans(cmd, virtVlan); -- 2.43.2
On 4/22/24 3:56 AM, Michal Privoznik wrote:
Since OVS keeps desired state in a DB, upon sudden crash of the host we may leave a port behind. There's no problem on VM shutdown or NIC hotunplug as we call corresponding del-port function (virNetDevOpenvswitchRemovePort()). But if the host suddenly crashes we won't ever do that. What happens next, is when OVS starts it finds desired state in its DB and creates a stale port.
OVS added support for transient ports in v2.5.0 (Feb 2016) and since its v2.9.0 it even installs a systemd service (ovs-delete-transient-ports) that automatically deletes transient ports on system startup. If we mark a port as transient then OVS won't restore its state on restart after crash.
This change may render "--may-exist" argument redundant, but I'm not sure about all the implications if it was removed. Let's keep it for now.
Resolves: https://gitlab.com/libvirt/libvirt/-/issues/615 Signed-off-by: Michal Privoznik <mprivozn@redhat.com> --- src/util/virnetdevopenvswitch.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/util/virnetdevopenvswitch.c b/src/util/virnetdevopenvswitch.c index f1765ae1c8..e23f4c83b6 100644 --- a/src/util/virnetdevopenvswitch.c +++ b/src/util/virnetdevopenvswitch.c @@ -164,7 +164,9 @@ int virNetDevOpenvswitchAddPort(const char *brname, const char *ifname,
cmd = virNetDevOpenvswitchCreateCmd(&errbuf); virCommandAddArgList(cmd, "--", "--may-exist", - "add-port", brname, ifname, NULL); + "add-port", brname, ifname, + "--", "set", "Port", ifname, "other_config:transient=true", + NULL);
virNetDevOpenvswitchConstructVlans(cmd, virtVlan);
While checking this out, I noticed that the machine I was testing on still has ports on its OVS bridge that I had manually created back in 2021 the last time I touched anything related to OVS :-). After adding a new port using the modified commandline, I rebooted the machine and the pre-existing "stale" interfaces were still there, but the one I had just created with transient=true was gone. Reviewed-by: Laine Stump <laine@redhat.com>
participants (2)
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Laine Stump -
Michal Privoznik