Anonymous user
Tech:Incidents/2015-04-04-prod7-resize: Difference between revisions
Jump to navigation
Jump to search
Tech:Incidents/2015-04-04-prod7-resize (view source)
Revision as of 21:28, 4 April 2015
, 9 years agono edit summary
imported>Addshore m (Addshore moved page Tech:Incidents/2015-04-04-prod6-resize to Tech:Incidents/2015-04-04-prod7-resize without leaving a redirect) |
imported>Addshore No edit summary |
||
Line 1:
'''15 mins of downtime''' were caused when '''resizing prod7''' from a 512MB DO instance to a 1GB DO instance (memory) and 20Gb to 30GB hdd.
== Details==
'''Why the resize needed to happen:'''
* static (nfs) which is hosted on prod7 had a very limited amount of space left.
* redis kept being killed OOM
'''What we were expecting to happen during resizing:'''
* page load speed be increased
* login / session ability be decreased
* Loading of files / static content js / css be impossible
'''What happened:'''
* Site was inaccessible for 15 mins while a snapshot was taken.
== Timeline ==
* Some testing happened prior to this seeing short bursts of no loading pages lasting around 30 - 60 seconds x2-3
* 20:14 - SF - [https://github.com/Orain/ansible-playbook/commit/890d63efbc718cf7859ba9503cc6ac7783685ee5 disable redis for MW]
* 20:32 - SF - [https://github.com/Orain/ansible-playbook/commit/54581a97ffdad0200d366d61b216498c31682163 reverted the above]
* 20:49 - AS - umount /mnt/mediawiki/private/uploads on prod11
* 20:53 - AS - Switch all mw traffic to hit prod11
* 20:54 - AS - Disable redis d on prod7
* 20:55 - AS - Shutdown prod7
* 20:58 - AS - Start snapshot of prod7 before resizing should happen
* 20:59 - '''MW pages stop being loaded, 504s!'''
* 21:14 - AS - Noticed [https://github.com/Orain/ansible-playbook/commit/54581a97ffdad0200d366d61b216498c31682163 this revert] and manually commented out redis stuff on prod11
* 21:14 - '''MW Pages start loading again with no styles of JS'''
* 21:15 - Snapshot of prod7 done - rebooted automatically
* 21:18 - AS - Shutdown prod7 again for resize
* 21:21 - AS - Resizing prod7 in DO
* 21:36 - Resize done! - Booting up
* 21:42 - AS - Rebooting mw servers prod8 and prod9
* 21:53 - AS - Switch all MW traffic to prod8 & prod9 '''All MW pages fully load again'''
* 21:53 - AS - Running ansible on prod11
* 21:58 - AS - Running ansible on prod10 (restoring original LB settings)
== lessons. ==
* When performing tasks like this make sure you have a fool proof plan and stick to every stage of it, double check each stage!!
* It may be nice to have a CDN infront of static meaning if static.orain.org is down pages still get JS CSS and files (We did once have this)
* We need to work out how login sessions can be handled without redis (so we can touch redis and people can still log in)
* NFS for static sucks? Maybe we could use S3? Perhaps? Or something similar?
| |||