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| | {{Incident | | {{Incident |
| − | |brief=We DDoS'd ourselves | + | |brief=Jukebox forgets how an audio happens. and suddenly remembers after scaring the Chief Engineer |
| | |severity=Moderate | | |severity=Moderate |
| − | |impact=Medium (Manual uploaded non-functional, one canceled show as a result - only a few seconds of dead air though) | + | |impact=High (Approx 1hr of dead air) |
| − | |start=04/11/2019 09:00 | + | |start=29/10/2019 11:02 |
| − | |end=05/11/2019 02:00 | + | |end=29/10/2019 12:26 |
| − | |mitigation=Stop the self-DDoS, restart samba, cry | + | |mitigation=Make sure the dead air alarm actually alerts when dead air happens |
| | |leader=Marks Polakovs (MP) | | |leader=Marks Polakovs (MP) |
| − | |others=Matthew Stratford (MS), Isaac Lowe (IL), Anthony Williams (AW) | + | |others=Morgan McKay(MM) |
| | }} | | }} |
| | | | |
| − | =URY is FUCKED (Frustratingly, URY Can't Keep Electronics Deferential)=
| + | Report under construction. |
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| − | '''This is still under construction because this literally just happened. When finished, I'll move this page into mainspace.'''
| + | =Summary= |
| | + | An (As of yet) not pinpointed issue caused Jukebox to fail to output to TX and Online for over an hour, despite the jukebox service still playing out music on Icecast and through the studio faders. Also the dead air alarm didnt tell anyone, the bastard. |
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| − | == Summary == | + | =Rough Sequence of Events= |
| | + | At around 11:02 Jukebox stops playing out audio to streaming and TX. Nobody notices as nobody listens to us, and the dead air detector sends no emails (Not that it could do much other than "We detected a silence, jukebox has been switched to jukebox!") |
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| − | A combination of a regularly scheduled offsite backup job and some strange behaviour by the studio PCs caused urybackup0 (specifically the music store) to have severely degraded performance. This in turn meant that music uploads to the central library, which normally take less than a minute, would take far longer, sometimes reaching 10 minutes and timing out. One show had to be canceled as a result because the host was not able to get all his music onto the system in time. The incident was not resolved, but mitigated by restarting Samba and the studio PCs.
| + | Having finished his morning lectures at around 12:00, MM enters the station and has a quick check of Jukebox via a desks AM feed. MM notices that no sound is coming out. Checking the feed from the AM2, Yamaha, and Icecast show the same. In a nervous panic MM alerts the committee, switching to red and playing out the Jukebox feed via the Pres Pc (Through Icecast, as Jukebox still was playing audio itself) at 12:11. At the time MM didnt know online was off as well as AM so ran into TX and stared at it. The transmitter was sitting there all happy and smug, no reflected power to speak of, just the ominous "Audio break" LED latched on. Having no idea what to check, MM comes back to the studio after a good 10 minute stare and contemplate to find that Jukebox is back on air playing as normal. |
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| − | == Timeline ==
| + | Turns out during this thoughtful TX stare someone came in and thought "Why the fuck is Red on thats not right!" and switched to Jukebox, which suddenly worked as normal. MM is very confused at this and declares the incident over. |
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| − | (all times GMT)
| + | =MPs Investigation= |
| − | | + | (BOLLACKOVS HERE PLS) |
| − | 9:00 - A regularly scheduled offsite backup job, which should be nightly and incremental... was not either of those things, for reasons unknown to man. It starts copying the entirety of the music store from backup0 to moyles (in IT Services TFTA data-center on East), which starts hammering the ZFS pools on backup0.
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| − | | |
| − | 20:48 - A member reports in Slack that they are unable to upload music. With just over an hour to go to their show, and 12 songs left to upload, they are forced to cancel.
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| − | | |
| − | 21:32 - MP alerts #computing in Slack to a serious incident. '''INCIDENT BEGINS.'''
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| − | 21:35 - MS reports that he had done some package updates on dolby(?) over the weekend, including ffmpeg, which may be causing stuck uploads. (This is eventually shown to be a red herring, but is important to include in this report.)
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| − | ''Between these entries, the computing team are sidetracked by an unrelated issue with MyRadio emails''
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| − | 22:30 - MS reports that ffmpeg conversions are working manually.
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| − | | |
| − | 22:36 - MP adds debug logging to the MyRadio upload controller, showing that it is hanging on a call to <code>move_uploaded_file</code>, a built-in PHP function. This leads him to point the finger to the music store.
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| − | | |
| − | 22:55 - AW logs on to backup0 to troubleshoot the pools, sees the degraded performance, but notes that zpool reports it is running fine.
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| − | 22:59 - AW notices the stuck(?) offsite backup job
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| − | | |
| − | 23:04 - AW notes that the RAID controllers are chugging as well
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| − | 23:10 - MP and AW decide to restart Samba, but have to wait until midnight as there is a show on air
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| − | | |
| − | 23:13 - AW notices that a Samba log is generating 100KB/s, and a 5MB log size limit means that it is rotating the log every few seconds. He also notes that the ARC cache is very low and that swap is not enabled. Around this time, a very frustrated MP goes for a run to let off steam.
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| − | | |
| − | 23:25 - AW notes that the incremental backup job... is not incremental... and has been sending the entire music dataset to moyles for over 12 hours
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| − | | |
| − | 23:35 - IL logs on and reports that the backup was ''intentionally'' not an incremental one (for reasons that the author (MP) does not yet understand). At 23:38 he kills it.
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| − | | |
| − | ''23:41 - MP gets lost in Alcuin.''
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| − | 23:49 - MS and IL report that the Windows 10 photos app is seemingly hammering backup0's shares
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| − | | |
| − | 00:05 - MP returns and stops samba. Performance on backup0 immediately jumps tenfold. However, MP screws up and doesn't realise that samba also handles his credentials (from the Windows domain).
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| − | 00:10 - MS logs on with his local account and restarts samba. Performance degrades immediately. MP notes that Xymon does not monitor samba on backup0 at all.
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| − | 00:14 - AW notes that the picture hammering noted earlier is likely one of the studio PCs.
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| − | | |
| − | 00:38-00:43 - MP remotes into wogan and restarts all the studio presenter and guest PCs. At 00:56 he reports that performance has not, in fact, improved substantially.
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| − | 01:06 - MS tests song uploading and notes that, while it is still slow, it has improved dramatically. '''INCIDENT ENDS'''
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| − | 01:26 - MP and the gang head to bed.
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