I2I: Error Reporting Migration Plan about error-tracker

[rcebulko]

At this point, with 20% of errors in Beta/Experimantal (and 100% of Nightly) reporting to the new endpoint, we can see a very tight sync between the legacy and new endpoints:

Green is GAE-Production; orange is GAE-Canary; purple is GCF-Canary.

This seems to indicate the new endpoint is logging as expected.

[rcebulko]

Last week due to cherry-picks and P0s, there was no release. I've updated all dates here to reflect the delay.

[rcebulko]

Promotion of the 20% split to the new endpoint seems to have gone off without a hitch so far:

Relative increases and decreases to reporting volume, throttle rates, and a handful of other metrics all seem to be in line with expectations.

It's vividly clear that the traffic to the new endpoint went up by almost exactly the 10x we'd expect:

It also appears that scaling up has made response times way more consistent (and lower in general)

Looks like this is scaling very well!

[rcebulko]

Vividly clear that the traffic to the new endpoint went up by almost exactly the 10x we'd expect: