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<p class="MsoNormal">+1 for using callbacks, we use the Mount and preUnMount callbacks on various things, e.g. before unmount, shutdown all the VMs running on the host, i.e. start and stop other things cleanly when the FS arrives/before it goes away.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Simon<o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black"><gpfsug-discuss-bounces@spectrumscale.org> on behalf of "stockf@us.ibm.com" <stockf@us.ibm.com><br>
<b>Reply-To: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Date: </b>Thursday, 14 March 2019 at 21:04<br>
<b>To: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Cc: </b>"gpfsug-discuss@spectrumscale.org" <gpfsug-discuss@spectrumscale.org><br>
<b>Subject: </b>Re: [gpfsug-discuss] Systemd configuration to wait for mount of SS filesystem<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">But if all you are waiting for is the mount to occur the invocation of the callback informs you the file system has been mounted. You would be free to start a command in the
background, with appropriate protection, and exit the callback script. Also, making the callback script run asynchronous means GPFS will not wait for it to complete and that greatly mitigates any potential problems with GPFS commands, if you need to run them
from the script.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><br>
</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Fred<br>
__________________________________________________<br>
Fred Stock | IBM Pittsburgh Lab | 720-430-8821<br>
stockf@us.ibm.com</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">----- Original message -----<br>
From: "Stephen R Buchanan" <stephen.buchanan@us.ibm.com><br>
Sent by: gpfsug-discuss-bounces@spectrumscale.org<br>
To: gpfsug-discuss@spectrumscale.org<br>
Cc:<br>
Subject: Re: [gpfsug-discuss] Systemd configuration to wait for mount of SS filesystem<br>
Date: Thu, Mar 14, 2019 4:52 PM<br>
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">The man page for mmaddcallback specifically cautions against running "commands that involve GPFS files" because it "may cause unexpected and undesired results, including loss
of file system availability." While I can imagine some kind of Rube Goldberg-esque chain of commands that I could run locally that would trigger the GPFS-filesystem-based commands I really want, I don't think mmaddcallback is the droid I'm looking for.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Helvetica Neue"">Stephen R. Wall Buchanan</span></b><span style="font-size:9.0pt;font-family:"Helvetica Neue""><br>
Sr. IT Specialist</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><br>
</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif">IBM Data & AI North America Government Expert Labs</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><br>
</span><span style="font-size:9.0pt;font-family:"Helvetica Neue"">+1 (571) 299-4601<br>
stephen.buchanan@us.ibm.com</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">----- Original message -----<br>
From: "Frederick Stock" <stockf@us.ibm.com><br>
Sent by: gpfsug-discuss-bounces@spectrumscale.org<br>
To: gpfsug-discuss@spectrumscale.org<br>
Cc: gpfsug-discuss@spectrumscale.org<br>
Subject: Re: [gpfsug-discuss] Systemd configuration to wait for mount of SS filesystem<br>
Date: Thu, Mar 14, 2019 4:17 PM<br>
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">It is not systemd based but you might want to look at the user callback feature in GPFS (mmaddcallback). There is a file system mount callback you could register.<o:p></o:p></span></p>
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</span><span style="font-size:12.0pt;font-family:"Arial",sans-serif">Fred<br>
__________________________________________________<br>
Fred Stock | IBM Pittsburgh Lab | 720-430-8821<br>
stockf@us.ibm.com</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif">----- Original message -----<br>
From: "Stephen R Buchanan" <stephen.buchanan@us.ibm.com><br>
Sent by: gpfsug-discuss-bounces@spectrumscale.org<br>
To: gpfsug-discuss@spectrumscale.org<br>
Cc:<br>
Subject: [gpfsug-discuss] Systemd configuration to wait for mount of SS filesystem<br>
Date: Thu, Mar 14, 2019 3:58 PM<br>
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">I searched the list archives with no obvious results.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">I have an application that runs completely from a Spectrum Scale filesystem that I would like to start automatically on boot, obviously after the SS filesystem mounts, on multiple
nodes. There are groups of nodes for dev, test, and production, (separate clusters) and the target filesystems are different between them (and are named differently, so the paths are different), but all nodes have an identical soft link from root (/) that
points to the environment-specific path. (see below for details)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">My first effort before I did any research was to try to simply use a directive of After=gpfs.service which anyone who has tried it will know that the gpfs.service returns as "started"
far in advance (and independently of) when filesystems are actually mounted.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">What I want is to be able to deploy a systemd service-unit and path-unit pair of files (that are as close to identical as possible across the environments) that wait for /appbin/builds/
to be available (/[dev|tst|prd]01/ to be mounted) and then starts the application. The problem is that systemd.path units, specifically the 'PathExists=' directive, don't follow symbolic links, so I would need to customize the path unit file for each environment
with the full (real) path. There are other differences between the environments that I believe I can handle by specifying an EnvironmentFile directive -- but that would come from the SS filesystem so as to be a single reference point, so it can't help with
the path unit.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">Any suggestions are welcome and appreciated.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">dev:(path names have been slightly generalized, but the structure is identical)<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">SS filesystem: /dev01<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">full path: /dev01/app-bin/user-tree/builds/<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">soft link: /appbin/ -> /dev01/app-bin/user-tree/<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">test:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">SS filesystem: /tst01<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">full path: /tst01/app-bin/user-tree/builds/<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">soft link: /appbin/ -> /tst01/app-bin/user-tree/<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">prod:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">SS filesystem: /prd01<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">full path: /prd01/app-bin/user-tree/builds/<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:9.0pt;font-family:"Arial",sans-serif">soft link: /appbin/ -> /prd01/app-bin/user-tree/<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.5pt;font-family:"Arial",sans-serif"> <o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:9.0pt;font-family:"Helvetica Neue"">Stephen R. Wall Buchanan</span></b><span style="font-size:9.0pt;font-family:"Helvetica Neue""><br>
Sr. IT Specialist</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><br>
</span><span style="font-size:9.0pt;font-family:"Arial",sans-serif">IBM Data & AI North America Government Expert Labs</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><br>
</span><span style="font-size:9.0pt;font-family:"Helvetica Neue"">+1 (571) 299-4601<br>
stephen.buchanan@us.ibm.com</span><span style="font-size:10.5pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Courier New"">_______________________________________________<br>
gpfsug-discuss mailing list<br>
gpfsug-discuss at spectrumscale.org<br>
<a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></span><span style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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gpfsug-discuss mailing list<br>
gpfsug-discuss at spectrumscale.org<br>
<a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></span><span style="font-size:9.0pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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gpfsug-discuss mailing list<br>
gpfsug-discuss at spectrumscale.org<br>
<a href="http://gpfsug.org/mailman/listinfo/gpfsug-discuss" target="_blank">http://gpfsug.org/mailman/listinfo/gpfsug-discuss</a></span><span style="font-size:12.0pt;font-family:"Arial",sans-serif"><o:p></o:p></span></p>
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