Planned for Thurs July 22nd at 15:00 UTC (08:00 PDT / 11:00 EDT / 17:00 CEST)
Completed on schedule, no issues to report.
Netops plan to adjust the buffer memory configuration for all switches in Eqiad Row C, to address tail drops observed on some of the devices, which is causing throughput issues.
This is an intrusive change, the Juniper documentation says it will bring all traffic on the row to a complete stop for a short time as the switches reconfigure themselves. Experience from the change to Row D indicates that this interruption is very brief (no ping loss was observed,) so the expected interruption is less than 1 second, and no interface state changes or similar will occur. As always there is a very small potential something will go wrong, we hit a bug etc, that will disrupt networking on the row for longer. TL;DR the interruption should be short enough nobody notices, but the row should be considered "at risk".
Service owners may want to take some pro-active steps in advance to failover / de-pool systems, to address this higher risk.
The complete list of servers in this row can be found here:
https://netbox.wikimedia.org/dcim/devices/?q=&rack_group_id=7&status=active&role=server
Summary of hosts by type here:
| Server Name / Prefix | Count | Relevant Team | Action Required | Action Status |
|---|---|---|---|---|
| mw | 39 | Service Operations | N | N/A |
| db | 23 | Data Persistence | N | N/A |
| an-worker | 16 | Analytics SREs | N | N/A |
| elastic | 9 | Search Platform SREs | N | N/A |
| ms-be | 7 | Data Persistence (Media Storage) | N | N/A |
| wtp | 6 | Service Operations | N | N/A |
| analytics | 5 | Analytics SREs | N | N/A |
| mc | 5 | Service Operations | N | N/A |
| cp | 4 | Traffic | depool the individual hosts with the depool command | Complete |
| dbproxy | 4 | Data Persistence | dbproxy1018 and dbproxy1019 owned by cloud-services-team, dbproxy1020 requires action after row D is done, dbroxy1021 doesn't | dbproxy1020 has been depooled by DBA |
| ganeti | 4 | Infrastructure Foundations | N | N/A |
| es | 3 | Data Persistence | N | N/A |
| kafka-jumbo | 3 | Analytics SREs & Infrastructure Foundations | N | N/A |
| kubernetes | 3 | Service Operations | N | N/A |
| clouddb | 2 | WMCS, with support from DBAs | Y | |
| labstore | 2 | WMCS | Y | |
| ms-fe | 2 | Data Persistence (Media Storage) | N | N/A |
| ores | 2 | Machine Learning SREs | N | N/A |
| wdqs | 2 | Search Platform SREs | N | N/A |
| alert1001 | 1 | Observability | N | N/A |
| an-conf1002 | 1 | Analytics | N | N/A |
| an-druid1002 | 1 | Analytics | N | N/A |
| an-test-master1002 | 1 | Analytics | N | N/A |
| an-test-worker1002 | 1 | Analytics | N | N/A |
| aqs1005 | 1 | Analytics SREs | N | N/A |
| backup1002 | 1 | Data Persistence | Heads up to Jaime before | N/A |
| cloudcontrol1005 | 1 | WMCS | ||
| cloudelastic1003 | 1 | WMCS | ||
| cloudmetrics1001 | 1 | WMCS | N | N/A |
| cumin1001 | 1 | Infrastructure Foundations | Y - Tell other SREs to use cumin2002 instead that day. Announce it few days earlier as some cookbooks takes days to run. | Complete |
| dbprov1003 | 1 | Data Persistence | N | N/A |
| dbstore1005 | 1 | Analytics SREs & Data Persistence | N | N/A |
| druid1002 | 1 | Analytics | N | N/A |
| dumpsdata1003 | 1 | Service Operations & Platform Engineering | Y | |
| kafka-main1003 | 1 | SRE | Y - Keith to depool in advance | Complete (re-pooled) |
| lvs1015 | 1 | Traffic | Failover to secondary (lvs1016 in row D) by stopping pybal with puppet disabled | Complete |
| maps1003 | 1 | N | N/A | |
| mc-gp1002 | 1 | Service Operations | N | N/A |
| ms-backup1002 | 1 | Data Persistence ?? | N | N/A |
| mwlog1002 | 1 | Service Operations | N | N/A |
| pc1009 | 1 | SRE Data Persistence (DBAs), with support from Platform and Performance | N | N/A |
| sessionstore1002 | 1 | Service Operations | N | N/A |
| thanos-be1003 | 1 | Observability | N | N/A |
| thanos-fe1003 | 1 | Observability | N | N/A |
VMs on this row are as follows:
| VM Name | Ganeti Host | Team | Action Required | Action Status |
|---|---|---|---|---|
| acmechief-test1001 | ganeti1009 | Traffic | N | N/A |
| acmechief1001 | ganeti1009 | Traffic | N | N/A |
| an-airflow1001 | ganeti1010 | Analytics SREs | N | N/A |
| an-tool1005 | ganeti1009 | Analytics SREs | N | N/A |
| an-tool1007 | ganeti1010 | Analytics SREs | N | N/A |
| doc1002 | ganeti1009 | N | N/A | |
| doh1001 | ganeti1011 | Traffic | N | N/A |
| etherpad1002 | ganeti1009 | Service Operations | N | N/A |
| flowspec1001 | ganeti1009 | Infrastructure Foundations | N | N/A |
| idp-test1001 | ganeti1010 | Infrastructure Foundations | N | N/A |
| kubemaster1002 | ganeti1010 | Service Operations | N | N/A |
| kubernetes1006 | ganeti1009 | Service Operations | N | N/A |
| kubestagetcd1006 | ganeti1012 | Service Operations | N | N/A |
| kubetcd1004 | ganeti1010 | Service Operations | N | N/A |
| logstash1009 | ganeti1010 | Observability | N | N/A |
| logstash1025 | ganeti1009 | Observability | N | N/A |
| matomo1002 | ganeti1009 | Analytics | N | N/A |
| miscweb1002 | ganeti1009 | Service Operations | N | N/A |
| ml-etcd1002 | ganeti1012 | ML team | N | N/A |
| mwdebug1001 | ganeti1010 | Service Operations | N | N/A |
| mx1001 | ganeti1009 | Infrastructure Foundations | N | N/A |
| ncredir1001 | ganeti1009 | Traffic | N | N/A |
| netflow1001 | ganeti1012 | Infrastructure Foundations | N | N/A |
| orespoolcounter1004 | ganeti1010 | Machine Learning SREs | N | N/A |
| ping1001 | ganeti1009 | Infrastructure Foundations | N | N/A |
| poolcounter1005 | ganeti1010 | Service Operations | N | N/A |
| puppetboard1001 | ganeti1010 | Infrastructure Foundations | N | N/A |
| puppetdb1002 | ganeti1012 | Infrastructure Foundations | Y (disable Puppet fleet-wide during maintenance) | Complete |
| registry1004 | ganeti1009 | Service Operations | N | N/A |
| rpki1001 | ganeti1009 | Infrastructure Foundations | N | N/A |
| seaborgium | ganeti1010 | Infrastructure Foundations | N | N/A |
| urldownloader1002 | ganeti1010 | Infrastructure Foundations | N | N/A |
I have listed the teams, and subscribed relevant individuals to this task, based mostly on the server names and info here: https://wikitech.wikimedia.org/wiki/SRE/Infrastructure_naming_conventions. Don't hesitate to add people I could have missed, or remove yourself from the task if you do not need to be involved.
Days Before:
- Prepare config changes (netops)
- Email ops list as a reminder
1h Before Window:
- Confirm switches are in a healthy state (snapshot MAC and ARP tables, port status, buffer usage) (netops)
- Warn people of the upcoming maintenance on IRC(netops)
After The Change
- Confirm switches are in a healthy state (snapshot MAC and ARP tables, port status, buffer usage, validate against prior values). (netops)