On 02/10, Rikimaru Honjo wrote: > Hello, > > I'd like to discuss about the following bug of os-brick. > > * os-brick's iscsi initiator unexpectedly reverts node.startup from > "automatic" to "manual". > https://bugs.launchpad.net/os-brick/+bug/1670237 > > The important point of this bug is: > > When os-brick initializes iscsi connections: > 1. os-brick will run "iscsiadm -m discovery" command if we use iscsi > multipath.
This only happens with a small number of cinder drivers, since most drivers try to avoid the discovery path due to the number of disadvantages it presents for a reliable deployment. The most notorious issue is that the path to the discovery portal on the attaching node is down you cannot attach the volume no matter how many of the other paths are up. > 2. os-brick will update node.startup values to "automatic" if we use iscsi. > 3. "iscsiadm -m discovery" command will recreate iscsi node repositories.[1] > As a result, node.startup values of already attached volumes will be revert > to default(=manual). > > Gorka Eguileor and I discussed how do I fix this bug[2]. > Our idea is this: > > 1. Confirm node.startup values of all the iscsi targets before running > discovery. > 2. Re-update node.startup values of all the iscsi targets after running > discovery. > > But, I afraid that this operation will take a long time. > I ran showing & updating node.startup values 100 times for researching. > As a result, it took about 4 seconds. > When I ran 200 times, it took about 8 seconds. > I think this is a little long. > > If we use multipath and attach 25 volumes, 100 targets will be created. > I think that updating 100 times is a possible use case. > > How do you think about it? > Can I implement the above idea? > The approach I proposed is on the review is valid, the flaw is in the specific implementation, you are doing 100 request where 4 would suffice. You don't need to do a request for each target-portal tuple, you only need to do 1 request per portal, which reduces the number of calls to iscsiadm from 100 to 4 in the case you mention. You can check all targets for an IP with: iscsiadm -m node -p IP This means that the performance hit from having 100 or 200 targets should be negligible. Cheers, Gorka. > [1]This is correct behavior of iscsiadm. > https://github.com/open-iscsi/open-iscsi/issues/58#issuecomment-325528315 > [2]https://bugs.launchpad.net/os-brick/+bug/1670237 > -- > _/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/_/ > Rikimaru Honjo > E-mail:honjo.rikim...@po.ntt-tx.co.jp > > > > __________________________________________________________________________ > 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 __________________________________________________________________________ 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
