Tech:Incidents/2015-04-04-prod7-resize: Difference between revisions
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imported>Cyborg (Undo revision 15983 by 94.198.98.67 (talk)) |
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ALL DATA IS SOLD BY ORAIN |
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An attempt to upgrade [[Tech:prod7|prod7]] from the 512MB to the 1024MB plan, caused 15 minutes of downtime, and more than 1 hour of [[wikipedia:FOUC|FOUC]] issues + cookie issues + login issues etc. |
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== Details == |
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'''Why the resize needed to happen:''' |
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* Static (NFS) which is hosted on prod7 had a very limited amount of space left (~1G). |
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* Redis kept being killed by the Linux Out-Of-Memory Killer |
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'''What we were expecting to happen during resizing:''' |
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* Page loading times increased due to expensive operations normally being cached now being executed all the time |
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* Login/session issues |
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* Loading of files/static content/js/css be impossible |
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'''What happened:''' |
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* Site was inaccessible for 15 mins while a snapshot was taken. |
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== Timeline == |
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* Some testing happened prior to this seeing short bursts of no loading pages lasting around 30 - 60 seconds x2-3 |
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* 20:14 - Southparkfan - [https://github.com/Orain/ansible-playbook/commit/890d63efbc718cf7859ba9503cc6ac7783685ee5 disable redis for MW] |
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* 20:32 - Southparkfan - [https://github.com/Orain/ansible-playbook/commit/54581a97ffdad0200d366d61b216498c31682163 reverted the above] |
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* 20:49 - Addshore - umount /mnt/mediawiki/private/uploads on prod11 |
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* 20:53 - Addshore - Switch all mw traffic to hit prod11 |
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* 20:54 - Addshore - Disable redis on prod7 |
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* 20:55 - Addshore - Shutdown prod7 |
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* 20:58 - Addshore - Start snapshot of prod7 before resizing should happen |
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* 20:59 - '''MW pages stop being loaded, 504s!''' |
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* 21:14 - Addshore - Noticed [https://github.com/Orain/ansible-playbook/commit/54581a97ffdad0200d366d61b216498c31682163 this revert] and manually commented out redis stuff on prod11 |
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* 21:14 - '''MW Pages start loading again with no styles of JS''' |
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* 21:15 - Snapshot of prod7 done - rebooted automatically |
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* 21:18 - Addshore - Shutdown prod7 again for resize |
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* 21:21 - Addshore - Resizing prod7 in DO |
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* 21:36 - Resize done! - Booting up |
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* 21:42 - Addshore - Rebooting mw servers prod8 and prod9 |
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* 21:53 - Addshore - Switch all MW traffic to prod8 & prod9 '''All MW pages fully load again''' |
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* 21:53 - Addshore - Running ansible on prod11 |
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* 21:58 - Addshore - Running ansible on prod10 (restoring original LB settings) |
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== Lessons == |
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* When performing tasks like this make sure you have a fool proof plan and stick to every stage of it, double check each stage! |
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* It may be nice to have a CDN in front of static meaning if static.orain.org is down pages still get JS CSS and files (We did once have this) |
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* We need to work out how login sessions can be handled without Redis (so we can touch Redis and people can still log in) |
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* NFS for static sucks? Maybe we could use S3? Perhaps? Or something similar? Or a server dedicated for |
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== Meta == |
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* Staff on hand: Addshore, Southparkfan |
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* Report published by: Addshore |
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* Timestamp: '''[[User:Addshore|<span style="color:black">·addshore·</span>]]''' <sup>[[User_talk:Addshore|<span style="color:black;">talk to me!</span>]]</sup> 22:28, 4 April 2015 (BST), [[User:Southparkfan|Southparkfan]] ([[User talk:Southparkfan|talk]]) 22:34, 4 April 2015 (BST) |
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Revision as of 18:05, 14 June 2015
ALL DATA IS SOLD BY ORAIN