On Wed, 2017-06-07 at 10:20 -0500, Matt Riedemann wrote: > The [libvirt]/live_migration_uri config option was deprecated in Ocata > [1] in favor of two other config options: > > live_migration_scheme: defaults to tcp (could be ssh), only used for > kvm/qemu virt types > > live_migration_inbound_addr: defaults to None, only used if doing a > non-tunneled live migration > > Those are used here: > > https://github.com/openstack/nova/blob/7815108d4892525b0047c787cbd2fe2f26c204c2/nova/virt/libvirt/ > driver.py#L652 > > If you leave a %s in the URI, the libvirt driver will replace that with > the destination target host. > > Devstack is configuring the live_migration_uri option and setting it to > "qemu+ssh://stack@%s/system" in our CI jobs. That %s gets replaced with > the target destination host IP as noted above. > > Since live_migration_uri is deprecated, I tried to update devstack to > use the new options that replace it [2], but then I ran into some > problems [3]. > > What I'm trying to do is continue to use ssh as the scheme since that's > what devstack sets up. So I set live_migration_scheme=ssh. > > Within the libvirt driver, it starts with a URL like this for qemu: > > qemu+%s://%s/system > > And does a string replace on that URL with (scheme, destination), which > would give us: > > qemu+ssh://<dest>/system > > The problem lies in the dest part. Devstack is trying to specify the > username for the ssh URI, so it wants "stack@%s" for the dest part. I > tried setting live_migration_inbound_addr="stack@%s" but that doesn't > work because the driver doesn't replace the dest on top of that again, > so we just end up with this: > > qemu+ssh://stack@%s/system > > Is there some other way to be doing this? We could try to use tunneling > but the config option help text for live_migration_tunnelled makes that > sound scary, e.g. "Enable this option will definitely > impact performance massively." Holy crap Scoobs, let's scram! > > Should we check if the scheme is ssh and try a final string replacement > with the destination host after we've already applied > (live_migration_scheme, live_migration_inbound_addr)? > > Other ideas? Given the bazillion config options related to libvirt live > migration, this is just a landmine of terrible so I'm interested in what > people are doing config-wise if they are using ssh.
I _think_ this bug [1] is the same thing, and I've some patches already up to resolve it [2]. Reviews appreciated :) Stephen [1] https://bugs.launchpad.net/nova/+bug/1671288 [2] https://review.openstack.org/#/c/456571/ > [1] https://review.openstack.org/#/c/410817/ > [2] https://review.openstack.org/#/c/471011/ > [3] > http://logs.openstack.org/19/471019/1/check/gate-tempest-dsvm-multinode-live-migration-ubuntu-xeni > al/546935b/logs/screen-n-cpu.txt.gz?level=TRACE#_Jun_05_15_56_42_184587 > __________________________________________________________________________ OpenStack Development Mailing List (not for usage questions) Unsubscribe: openstack-dev-requ...@lists.openstack.org?subject:unsubscribe http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev