Re: [gpfsug-discuss] wait for mount during gpfs startup
On Thu, Apr 30, 2020 at 12:50:27PM +0200, Ulrich Sibiller wrote: > Am 28.04.20 um 15:57 schrieb Skylar Thompson: > >> Have you looked a the mmaddcallback command and specifically the file > system mount callbacks? > > > We use callbacks successfully to ensure Linux auditd rules are only loaded > > after GPFS is mounted. It was easy to setup, and there's very fine-grained > > events that you can trigger on: > > Thanks. But how do set this up for a systemd service? Disable the dependent > service and start it > from the callback? Create some kind of state file in the callback and let the > dependent systemd > service check that flag file in a busy loop? Use inotify for the flag file? In the pre-systemd days, I would say just disable the service and let the callback handle it. I do see your point, though, that you lose the other systemd ordering benefits if you start the service from the callback. Assuming you're still able to start the service via systemctl, I would probably just leave it disabled and let the callback handle it. In the case of auditd rules, it's not actually a service (just a command that needs to be run) so we didn't run into this specific problem. -- -- Skylar Thompson (skyl...@u.washington.edu) -- Genome Sciences Department, System Administrator -- Foege Building S046, (206)-685-7354 -- University of Washington School of Medicine ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] wait for mount during gpfs startup
I now better understand the functionality you were aiming to achieve. You want anything in systemd that is dependent on GPFS file systems being mounted to block until they are mounted. Currently we do not offer any such feature though as Carl Zetie noted there is an RFE for such functionality, RFE 125955 ( https://www.ibm.com/developerworks/rfe/execute?use_case=viewRfe&CR_ID=125955 ). For the mmaddcallback what I was thinking could resolve your problem was for you to create a either a "startup" callback or "mount" callbacks for your file systems. I thought you could use those callbacks to track the file systems of interest and then use the appropriate means to integrate that information into the flow of systemd. I have never done this so perhaps it is not possible. Regards, The Spectrum Scale (GPFS) team -- If you feel that your question can benefit other users of Spectrum Scale (GPFS), then please post it to the public IBM developerWroks Forum at https://www.ibm.com/developerworks/community/forums/html/forum?id=----0479 . If your query concerns a potential software error in Spectrum Scale (GPFS) and you have an IBM software maintenance contract please contact 1-800-237-5511 in the United States or your local IBM Service Center in other countries. The forum is informally monitored as time permits and should not be used for priority messages to the Spectrum Scale (GPFS) team. From: Ulrich Sibiller To: gpfsug-discuss@spectrumscale.org Date: 04/30/2020 06:57 AM Subject:[EXTERNAL] Re: [gpfsug-discuss] wait for mount during gpfs startup Sent by:gpfsug-discuss-boun...@spectrumscale.org Am 28.04.20 um 15:57 schrieb Skylar Thompson: >> Have you looked a the mmaddcallback command and specifically the file system mount callbacks? > We use callbacks successfully to ensure Linux auditd rules are only loaded > after GPFS is mounted. It was easy to setup, and there's very fine-grained > events that you can trigger on: Thanks. But how do set this up for a systemd service? Disable the dependent service and start it from the callback? Create some kind of state file in the callback and let the dependent systemd service check that flag file in a busy loop? Use inotify for the flag file? Uli -- Science + Computing AG Vorstandsvorsitzender/Chairman of the board of management: Dr. Martin Matzke Vorstand/Board of Management: Matthias Schempp, Sabine Hohenstein Vorsitzender des Aufsichtsrats/ Chairman of the Supervisory Board: Philippe Miltin Aufsichtsrat/Supervisory Board: Martin Wibbe, Ursula Morgenstern Sitz/Registered Office: Tuebingen Registergericht/Registration Court: Stuttgart Registernummer/Commercial Register No.: HRB 382196 ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org https://urldefense.proofpoint.com/v2/url?u=http-3A__gpfsug.org_mailman_listinfo_gpfsug-2Ddiscuss&d=DwICAg&c=jf_iaSHvJObTbx-siA1ZOg&r=IbxtjdkPAM2Sbon4Lbbi4w&m=KmkFZ30Ey3pB4QnhsP2vS2mmojVLAWGrIiStGaE0320&s=VHWoLbiq119iFhL724WAQwg4dSJ3KRNVSXnfrFBv9RQ&e= ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] wait for mount during gpfs startup
Am 28.04.20 um 13:38 schrieb Jonathan Buzzard: Yuck, and double yuck. There are many things you can say about systemd (and I have a choice few) but one of them is that it makes this sort of hackery obsolete. At least that is one of it goals. A systemd way to do it would be via one or more helper units. So lets assume your GPFS file system is mounted on /gpfs, then create a file called ismounted.txt on it and then create a unit called say gpfs_mounted.target that looks like # gpfs_mounted.target [Unit] TimeoutStartSec=infinity ConditionPathExists=/gpfs/ismounted.txt ExecStart=/usr/bin/sleep 10 RemainAfterExit=yes Then the main unit gets Wants=gpfs_mounted.target After=gpfs_mounted.target If you are using scripts in systemd you are almost certainly doing it wrong :-) Yes, that the right direction. But still not the way I'd like it to be. First, I don't really like the flag file stuff. Imagine the mess you'd create if multiple services would require flag files... Second, I am looking for an all_local target. That one cannot be solved using this approach, right? (same for all_remote or all) Uli -- Science + Computing AG Vorstandsvorsitzender/Chairman of the board of management: Dr. Martin Matzke Vorstand/Board of Management: Matthias Schempp, Sabine Hohenstein Vorsitzender des Aufsichtsrats/ Chairman of the Supervisory Board: Philippe Miltin Aufsichtsrat/Supervisory Board: Martin Wibbe, Ursula Morgenstern Sitz/Registered Office: Tuebingen Registergericht/Registration Court: Stuttgart Registernummer/Commercial Register No.: HRB 382196 ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] wait for mount during gpfs startup
Am 28.04.20 um 13:55 schrieb Hannappel, Juergen: a gpfs.mount target should be automatically created at boot by the systemd-fstab-generator from the fstab entry, so no need with hackery like ismountet.txt... A generic gpfs.mount target does not seem to exist on my system. There are only specific mount targets for the mounted gpfs filesystems. So I'd need to individually configure each depend service on each system with the filesystem for wait for. My approach was more general in just waiting for all_local gpfs filesystems. So I can use the same configuration everywhere. Besides, I have once tested and found that these targets are not usable because of some oddities but unfortunately I don't remember details. But the outcome was my script from the initial post. Maybe it was that there's no automatic mount target for all_local, same problem as above. Uli -- Science + Computing AG Vorstandsvorsitzender/Chairman of the board of management: Dr. Martin Matzke Vorstand/Board of Management: Matthias Schempp, Sabine Hohenstein Vorsitzender des Aufsichtsrats/ Chairman of the Supervisory Board: Philippe Miltin Aufsichtsrat/Supervisory Board: Martin Wibbe, Ursula Morgenstern Sitz/Registered Office: Tuebingen Registergericht/Registration Court: Stuttgart Registernummer/Commercial Register No.: HRB 382196 ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] wait for mount during gpfs startup
Am 28.04.20 um 15:57 schrieb Skylar Thompson: >> Have you looked a the mmaddcallback command and specifically the file system mount callbacks? > We use callbacks successfully to ensure Linux auditd rules are only loaded > after GPFS is mounted. It was easy to setup, and there's very fine-grained > events that you can trigger on: Thanks. But how do set this up for a systemd service? Disable the dependent service and start it from the callback? Create some kind of state file in the callback and let the dependent systemd service check that flag file in a busy loop? Use inotify for the flag file? Uli -- Science + Computing AG Vorstandsvorsitzender/Chairman of the board of management: Dr. Martin Matzke Vorstand/Board of Management: Matthias Schempp, Sabine Hohenstein Vorsitzender des Aufsichtsrats/ Chairman of the Supervisory Board: Philippe Miltin Aufsichtsrat/Supervisory Board: Martin Wibbe, Ursula Morgenstern Sitz/Registered Office: Tuebingen Registergericht/Registration Court: Stuttgart Registernummer/Commercial Register No.: HRB 382196 ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
