Redis

Redis is an open-source, in-memory data structure store that is used as a database, cache, and message broker. In Mastodon, Redis is used for various purposes to improve the performance, scalability, and reliability of the platform.

Starting in Mastodon 4.4, Redis folks (such as Valkey) or alternatives that implement the Redis API are supported for use.

We use the Dragonfly controlled by their Kubernetes Operator. We have three databases, all in a high-availibility configuration.

Mastodon
Sidekiq
Cache

Our connection to Dragonfly is configured as the REDIS_URL variable using a connection string.

REDIS_URL=redis://dragonfly-db-mastodon.default.svc.cluster.local
SIDEKIQ_REDIS_URL=redis://dragonfly-db-sidekiq.default.svc.cluster.local
CACHE_REDIS_URL=redis://dragonfly-db-cache.default.svc.cluster.local
REDIS_DRIVER=ruby

In addition to the HA-configuration, regular backup operations copy the data to an secure S3 bucket.

InfrastructureProviders

InfrastructureSidekiq