Description of problem: After upgrading to systemd-216-5.fc21.x86_64, /dev/disk/by-path is missing when mounting iscsi volumes. The systemd-215-19.fc21.x86_64 package is unaffected. ** This breaks OpenStack nova's volume handling as it depends heavily on the predictably-named /dev/disk/by-path directory. ** Version-Release number of selected component (if applicable): systemd-216-5.fc21.x86_64 <-- affected systemd-215-19.fc21.x86_64 <-- not affected Steps to Reproduce: 1. Create iscsi target on another machine 2. Do iscsiadm discovery and log into the other machine using iscsiadm 3. /dev/sdX appears in fdisk -l output on the initiator machine 4. /dev/disk/by-path is missing on the initiator machine when running systemd-216-5.fc21.x86_64 Additional info: A question was raised about this on the systemd-devel list earlier this month[1]. There's also a LaunchPad ticket[2] and here is a link the problematic systemd patch[3]. [1] http://lists.freedesktop.org/archives/systemd-devel/2014-October/023705.html [2] https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1321816 [3] http://cgit.freedesktop.org/systemd/systemd/commit/?id=e98bbfd20
Let me quote Kay's reply: > It is not about non-conflicting numbers, it is about predictability of > the numbers. The SCSI enumeration numbers are not predictable and > depend on enumeration or discovery order. The numbers used in by-path > links would need to be able to be calculated before the device is > connected. > The by-path links with non-predictable numbers are pointless and wrong > to create. It is expected that only a very limited subset of devices > support by-path, there is nothing wrong if iSCSI does not have them. Does this incorrect? Are the iscsi paths predictable?
I've read some of that thread, and while it does make some sense, it seems like the by-path directory should still be made available should a user want to use it. A lack of by-path links will disrupt how OpenStack's nova-volume works. I'm working on a patch for the systemd-216-5 package this morning and I'll test it on a 200+ node environment to verify. I'll report back in a few hours.
I applied a one-line patch to systemd that brings back by-path links for iscsi volumes: Source: https://github.com/major/systemd/commit/fcc922e74dcc4f722c8f04c3d8303481da3ae036 Build: http://koji.fedoraproject.org/koji/taskinfo?taskID=7961229 It's currently running on 204 servers within my testing environment and the OpenStack nova-volume code works properly with it. I tested it against several iscsi targets as well. What are the the potential pitfalls to applying this patch to the Fedora systemd package? This seems to restore the functionality prior to the systemd patch[1] from August without causing any significant headaches for me so far. [1] http://cgit.freedesktop.org/systemd/systemd/commit/?id=e98bbfd20
kmod-18-4.fc21,systemd-216-7.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/kmod-18-4.fc21,systemd-216-7.fc21
kmod-18-4.fc21,systemd-216-9.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/kmod-18-4.fc21,systemd-216-9.fc21
kmod-18-4.fc21,systemd-216-10.fc21 has been submitted as an update for Fedora 21. https://admin.fedoraproject.org/updates/kmod-18-4.fc21,systemd-216-10.fc21
Package kmod-18-4.fc21, systemd-216-10.fc21: * should fix your issue, * was pushed to the Fedora 21 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing kmod-18-4.fc21 systemd-216-10.fc21' as soon as you are able to, then reboot. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2014-14307/kmod-18-4.fc21,systemd-216-10.fc21 then log in and leave karma (feedback).
Package kmod-18-4.fc21, systemd-216-11.fc21: * should fix your issue, * was pushed to the Fedora 21 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing kmod-18-4.fc21 systemd-216-11.fc21' as soon as you are able to, then reboot. Please go to the following url: https://admin.fedoraproject.org/updates/FEDORA-2014-14307/kmod-18-4.fc21,systemd-216-11.fc21 then log in and leave karma (feedback).
kmod-18-4.fc21, systemd-216-11.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.