No connection when using ioredis in a Docker Swarm stack.

[matthias-hampel]

I'm trying to deploy a web application (six Node.js applications and a Redis database) with Docker Swarm.

The web applications writing data into the Redis database and using ioredis.

Once I deploy the Redis database on another node than the web applications are running, they cannot connect to Redis.

I already changed the Redis configuration and set the following properties (this is just an excerpt):

bind 
protected-mode no
requirepass foobared0.0.0.0

The connection string should the look like this:

redis://default:foobared@redis:6379/1

I have checked it, by placing the web applications and Redis on the same machine, where then everything works fine.

But once I distribute the containers over all nodes, the web apps cannot connect to Redis. I created a network that is assigned to all services:

services:
  redis:
    image: redis:latest
    deploy:
      placement:
        constraints: [node.role == manager]
    networks:
      - redis
    command: redis-server /usr/local/etc/redis/redis.conf
    configs:
      - source: redis
        target: /usr/local/etc/redis/redis.conf      
    ports:
      - 6379:6379

networks:
  redis: 
    driver: overlay

One thing that might be important is, that I can reach the Redis host from the web app containers. I tested it by running:

ping redis
It always gave me a response.

I also tried to connect with redis-cli from one of the containers which also worked fine:

root@5495c5a491bd:/app# redis-cli -h redis
redis:6379> auth default foobared 
OK
redis:6379> ping
PONG
redis:6379> 

At this point, I think it could be a problem with ioredis but I am just not sure and I don't know where I can dig deeper to solve the problem.

[victorcastro89]

I have the same issue

[matthias-hampel]

@victorcastro89 I couldn't find the issue and ended up switching to redis which works fine for me.