We need to ramp-up usage of php7 to 100% both on the appserver and the API cluster.
This means progressively changing the sampling rate on both clusters to 5,10, 20, 50 and 100%.
For the API cluster, we will convert each API server to serve only via php7.2-fpm. Each API server serves ~2% of traffic.
Once that's done, and we're confident we won't need to revert, we will need to cleanup:
* Remove the conditional in the virtual hosts, send all requests to php by default.
* Remove all the code from the WikimediaEvents extension that sets the cookie for this transition
* Remove any code in apache/varnish that does set the cookie for API requests
#### Record of going live for appservers:
| Level | Went live | Git change |
| ----- | ---------- | ---------- |
| 0.1% | 2019.03.25 | 5a270bbebf |
| 1% | 2019.04.30 | 88984d4d20 |
| 5% | 2019.05.02 | 8afada66e1 |
| 10% | 2019.05.21 | cee99d4ca6 |
| 20% | 2019.05.28 | 4ffc48ff58 |
| 33% | 2019.08.22 | 1b3990ef77 |
| 20% | 2019.08.22 | 7efa56c1f0 |
| 33% | 2019.09.09 | 559c8afb19 |
|Proportion of [[https://gerrit.wikimedia.org/r/plugins/gitiles/operations/puppet/+/HEAD/conftool-data/node/codfw.yaml#77|servers]] | Went live | Server(s) | Git Change |
| ----- | ---------- | ------ | -------- |
| 1/51 | 2019.08.01 | mw1270 | e0d83ea6 |
#### Record of going live for API cluster:
##### eqiad
| Proportion of [[https://gerrit.wikimedia.org/r/plugins/gitiles/operations/puppet/+/HEAD/conftool-data/node/eqiad.yaml#57|servers]] | Went live | Server(s) | Git Change |
| ----- | ---------- | ---------- | ------------ |
| 1/47 | 2019.05.30 | mw1348 | 35b2eca |
| 2/47 | 2019.07.30 | mw1347 | 55e5091 |
| 5/51 | 2019.08.08 | mw122[1-3] | 845752ac43fc |
| 10/51 | 2019.08.12 | mw122[4-8} | 1a7073eef400 |
##### codfw
| Proportion of [[https://gerrit.wikimedia.org/r/plugins/gitiles/operations/puppet/+/HEAD/conftool-data/node/codfw.yaml#77|servers]] | Went live | Server(s) | Git Change |
| ----- | ---------- | ------ | ------- |
| 1/51 | 2019.05.30 | mw2135 | e13905d |
| 2/51 | 2019.07.30 | mw2136 | 55e5091 |