Maps/Infrastructure plans

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This page describes plans and not the current state of maps servers

Constraints

When updating vector tile styles you may run into a scenario where there is a schema change, and the new style and old style vector and raster parts are not forward or backwards compatible with each other. These should be avoided, but are sometimes necessary.

Additionally, we need to withstand the following while handling a schema change:

- Two specific servers failing

- One specific server failing and a datacenter failing

Desirable properties are the abilities to

- take a database server offline to run maintenance (e.g. reclustering),

- reimport with updated software

- upgrade other software

Architecture

The maps cluster will consist of four machines in each datacenter. Under normal operation, requests can go to any of the four machines. When a schema upgrade is necessary, the following needs to be done