Rails "Redis::CannotConnectError: Connection refused" in CI

Rails tried to reach Redis for the cache, Action Cable, or Sidekiq and the connection was refused. In CI this means no Redis service container is running, or REDIS_URL points at a host and port nothing is listening on.

What this error means

A step fails with "Redis::CannotConnectError: Error connecting to Redis on localhost:6379 (Errno::ECONNREFUSED)".

Redis::CannotConnectError:
Error connecting to Redis on localhost:6379 (Errno::ECONNREFUSED)

Common causes

No Redis service container

The job uses a Redis-backed cache or queue but has no services: redis, so nothing listens on 6379.

REDIS_URL does not match the service

The URL targets the wrong host or port, or the service maps a different port, so the connection is refused.

How to fix it

Add a Redis service with a health check

1. Declare a redis service and map port 6379.
2. Add a redis-cli ping health check so steps wait for readiness.
3. Set REDIS_URL to the mapped host and port.

services:
  redis:
    image: redis:7
    ports: ['6379:6379']
    options: >-
      --health-cmd "redis-cli ping" --health-interval 10s
      --health-timeout 5s --health-retries 5

Point Rails at the Redis service

Export REDIS_URL so the cache, cable, and Sidekiq connect to the container.

env:
  REDIS_URL: redis://localhost:6379/0

How to prevent it

• Add a Redis service and health check when tests use a Redis-backed store.
• Keep REDIS_URL aligned with the service port mapping.
• Use :test cache/queue adapters where a real Redis is not needed.

Related guides