Warning This document has not been updated for a while now. It may be out of date.

Last updated: 9 Jun 2020

govuk-aws: 29. Combine api-redis into backend-redis

Date: 2017-09-14

Status

Accepted

Context

We currently have 3 Redis instances that we run in Elasticache:

• backend-redis
• logs-redis
• api-redis

Most applications use backend-redis, the logging cluster uses logs-redis (which should soon be replaced), and Rummager uses api-redis.

This was traditionally the case because Rummager lived in a different vDC to redis-1/redis-2, but this is no longer a concern in AWS.

Decision

Update Rummager configuration so it uses backend-redis, and remove api-redis.

Consequences

Everything relying on a single redis instance could potentially have impact if there is an issue with that Elasticache instance.

We will save money on not running multiple Elasticache instances.