ERROR: Error fetching job: READONLY You can't write against a read only replica.

[Annastacia-dev]

I'm using sidekiq in my rails app for background processing that depends on a redis container that I have in my compose.yml

 redis:
    image: redis:latest
    container_name: redis_server
    ports:
      - "6379:6379"
    command: redis-server --appendonly yes
    sysctls:
     - net.core.somaxconn=1024
    volumes:
      - redis_data:/data

It works most of the time but sometimes I get this error

 ERROR: Error fetching job: READONLY You can't write against a read only replica.
 2025-03-16T06:30:27.285Z pid=1 tid=j7p WARN: RedisClient::ReadOnlyError: READONLY You can't write against a read only replica. (redis://redis:6379)
 2025-03-16T06:30:27.286Z pid=1 tid=j7p WARN:
 2025-03-16T06:30:28.756Z pid=1 tid=10y1 WARN: Unable to flush stats: READONLY You can't write against a read only replica.
 2025-03-16T06:30:28.771Z pid=1 tid=10y1 ERROR: heartbeat: READONLY You can't write against a read only replica.
 2025-03-16T06:30:35.400Z pid=1 tid=j7p INFO: Redis is online, 8.11720569897443 sec downtime

Which removes all my cron jobs added to the queue and I have to restart my containers.

I have never used redis inside docker before and I haven't faced this issue when using redis anywhere else before.

Any idea what the cause is and how I could fix it would be highly appreciated.