Sorry for the late response. On Mon, Mar 4, 2013 at 7:06 PM, Ansis Atteka <aatt...@nicira.com> wrote: > On Mon, Mar 4, 2013 at 12:08 PM, Ernesto Domato <edo...@gmail.com> wrote: > > If you do not block on interface creation and libvirt/Open vSwitch > init.d dependencies are not right, then I think you might end up with > another race condition, where VM automatic start-up would fail. > Imagine that: > 1. Neither Open vSwitch or libvirt are running > 2. libvirt starts up > 3. libvirt tries to spin up VM and executes "ovs-vsctl --no-wait > --timeout=5 -- del-port ... -- add-port ..." command. After 5 seconds > this command times out, because Open vSwitch wasn't running > 4. After 6 seconds Open vSwitch starts up, but VM still remains down. > > This means that you will have to manually start the VM one more time. >
Ok, so I guess that to solve this problem, the right solution would be that libvirt wait till OVS is up by not timing out, right? I think that could be a good idea, I'll write a new patch for libvirt then and send it to them for comments. >> >> I also added "--no-wait --timeout 5" when libvirt goes down so it can >> timeout if ovs-switch is down. > Just curious, but wasn't this part already solved with libvirt commit > 98e732fc34a47ad9dfdb64aa4207623ee4c1ebcd (network: prevent infinite > hang if ovs-vswitchd isn't running)? Are you using libvirt that has > this patch? > Ok, I'm using the stable version of libvirt and that fix is in experimental package. Anyway, this fix only adds the timeout flag when deleting the interface from OVS which does that libvirt don't hang trying to delete the interface if OVS is down. But it doesn't fix the issue that the OVS-DB still have the reference to the virtual interface and so, when you bring the virtual machine up again, it doesn't response because of this. As you (Ansis Atteka I guess) recommended before, my patch adds that libvirt try to delete (with the --if-exists flag) the interface before adding it again so that problem is resolved. > By the way I tried to execute the same commands as libvirt would have > executed. Except I ran them directly in the shell. What I observed is > that ovs-vsctl did not block indefinitely for this corner case: > > root@ubuntu:~# service openvswitch-switch stop > * ovs-brcompatd is not running > * Killing ovs-vswitchd (13202) > * Killing ovsdb-server (13193) > root@ubuntu:~# ovs-vsctl --timeout=5 -- --if-exists del-port p0 > Mar 04 13:39:14|00002|stream_unix|ERR|/tmp/stream-unix.13222.0: > connection to /var/run/openvswitch/db.sock failed: No such file or > directory > Mar 04 13:39:14|00003|reconnect|WARN|unix:/var/run/openvswitch/db.sock: > connection attempt failed (No such file or directory) > Mar 04 13:39:15|00004|stream_unix|ERR|/tmp/stream-unix.13222.1: > connection to /var/run/openvswitch/db.sock failed: No such file or > directory > Mar 04 13:39:15|00005|reconnect|WARN|unix:/var/run/openvswitch/db.sock: > connection attempt failed (No such file or directory) > Mar 04 13:39:17|00006|stream_unix|ERR|/tmp/stream-unix.13222.2: > connection to /var/run/openvswitch/db.sock failed: No such file or > directory > Mar 04 13:39:17|00007|reconnect|WARN|unix:/var/run/openvswitch/db.sock: > connection attempt failed (No such file or directory) > Alarm clock > root@ubuntu:~# > > I tried this with Open vSwitch: 1.4.3-0ubuntu2.1. Are you seeing the > same effect with your Open vSwitch? Yes, I see the same behavior but after applying the patch that adds the --timeout flag to the older version of libvirt that is currently in Debian as stable but is incorporated in experimental package. So, summarizing, what I'll do is to download the GIT version of libvirt, make patch that just tries to delete the interface before adding it again when the virtual machine is going up and do it in a separate call to ovs-vsctl so when adding the interface, it wait for OVS to be up. Is that the way to solve this problem?, what do you think? :-) Thanks Ernesto _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
