[Engineering] [Ops] Data center switch-over moving ahead next week: please stay available :)

Thu Apr 21 18:34:33 UTC 2016

Well planned, well done!

Mark thanks for the summaries and hours dedicated to making this all work
well.  Thanks to the many teams working together to complete this effort.

On Thu, Apr 21, 2016 at 11:55 AM, Arthur Richards <arichards at wikimedia.org>
wrote:

> This is so rad - congratulations indeed to everyone who's been working on
> this!
>
> On Thu, Apr 21, 2016 at 8:44 AM, Toby Negrin <tnegrin at wikimedia.org>
> wrote:
>
>> Congrats Mark and everyone else involved. This is a big step for
>> reliability and performance of the sites and a difficult technical task to
>> say the least.
>>
>> Well done!
>>
>> -Toby
>>
>> On Thu, Apr 21, 2016 at 8:37 AM, Mark Bergsma <mark at wikimedia.org> wrote:
>>
>>> We've just completed the switch back, and all services are running from
>>> our main data center eqiad (Ashburn) again.
>>>
>>> The process went very smooth this time around. In the past two days
>>> leading up to this, we've been able to either fix or work around the most
>>> important issues we encountered on Tuesday. This meant that we had no real
>>> setbacks or unanticipated delays today, and therefore were able to complete
>>> the most time pressing and user-impacting part (during which MediaWiki is
>>> read-only) in 20 minutes, down from ~45 minutes two days ago.
>>>
>>> However, we'll be doing this again in the future, and until then we'll
>>> work on improving and further automating this process to get it down to
>>> hopefully much lower levels of impact and duration.
>>>
>>> Please let us know if you see any issues which may be caused by the
>>> switch-over(s).
>>>
>>> Thanks much to everyone involved!
>>>
>>> Mark
>>>
>>>
>>>
>>> On Thu, Apr 21, 2016 at 3:53 PM, Mark Bergsma <mark at wikimedia.org>
>>> wrote:
>>>
>>>> Hi everyone,
>>>>
>>>> After we've been successfully serving our sites from our backup
>>>> data-center codfw (Dallas) for the past two days, we're now starting our
>>>> switch back to eqiad (Ashburn) as planned[1].
>>>>
>>>> We've already moved cache traffic back to eqiad, and within the next
>>>> minutes, we'll disable editing by going read-only for approximately 30
>>>> minutes - hopefully a bit faster than 2 days ago.
>>>>
>>>> [1] http://blog.wikimedia.org/2016/04/11/wikimedia-failover-test/
>>>>
>>>> On Tue, Apr 19, 2016 at 6:00 PM, Mark Bergsma <mark at wikimedia.org>
>>>> wrote:
>>>>
>>>>> Hi all,
>>>>>
>>>>> Today the data center switch-over commenced as planned, and has just
>>>>> fully completed successfully. We are now serving our sites from codfw
>>>>> (Dallas, Texas) for the next 2 days if all stays well.
>>>>>
>>>>> We switched the wikis to read-only (editing disabled) at 14:02 UTC,
>>>>> and went back read-write at 14:48 UTC - a little longer than planned. While
>>>>> edits were possible then, unfortunately at that time Special:Recent Changes
>>>>> (and related change feeds) were not yet working due to an unexpected
>>>>> configuration problem with our Redis servers until 15:10 UTC, when we found
>>>>> and fixed the issue. The site has stayed up and available for readers
>>>>> throughout the entire migration.
>>>>>
>>>>> Overall the procedure was a success with few problems along the way.
>>>>> However we've also carefully kept track of any issues and delays we
>>>>> encountered for evaluation to improve and speed up the procedure, and
>>>>> reducing impact to our users - some of which will already be implemented
>>>>> for our switch back on Thursday.
>>>>>
>>>>> We're still expecting to find (possibly subtle) issues today, and
>>>>> would like everyone who notices anything to use the following channels to
>>>>> report them:
>>>>>
>>>>> 1. File a Phabricator issue with project #codfw-rollout
>>>>> 2. Report issues on IRC: Freenode channel #wikimedia-tech (if urgent)
>>>>> 3. Send an e-mail to the Operations list: ops at lists.wikimedia.org
>>>>>
>>>>> We're not done yet, but thanks to all who have helped so far. :-)
>>>>>
>>>>> Mark
>>>>>
>>>>
>>>> --
>>>> Mark Bergsma <mark at wikimedia.org>
>>>> Lead Operations Architect
>>>> Director of Technical Operations
>>>> Wikimedia Foundation
>>>>
>>>
>>>
>>>
>>> --
>>> Mark Bergsma <mark at wikimedia.org>
>>> Lead Operations Architect
>>> Director of Technical Operations
>>> Wikimedia Foundation
>>>
>>> _______________________________________________
>>> Ops mailing list
>>> Ops at lists.wikimedia.org
>>> https://lists.wikimedia.org/mailman/listinfo/ops
>>>
>>>
>>
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>>
>>
>
>
> --
> Arthur Richards
> Team Practices Manager
> [[User:Awjrichards]]
> IRC: awjr
> +1-415-839-6885 x6687
>
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