如何在旧版Docker Swarm中使用Docker Compose

Question

I am trying to deploy my app with Compose and Swarm . Currently I don't want to upgrade my docker-compose.yaml from v2 to v3 . So I am only able to do that with standalone(legacy) swarm rather that docker swarm mode based on Stoneman's answer and official Swarm documents.

Following the official instruction , I successfully set up a swarm cluster. I ran docker -H :4000 info on the swarm manager node to check the swarm cluster status, as shown below. There are two other worker nodes in this cluster. Next, I want to create an overlay network with this cluster and refer this network in the docker-compose.yaml . But when I ran docker -H :4000 network create -d overlay test on the swarm manager node to create the netwrok, it reported error: Error response from daemon: Error response from daemon: This node is not a swarm manager. Use "docker swarm init" or "docker swarm join" to connect this node to swarm and try again. Error response from daemon: Error response from daemon: This node is not a swarm manager. Use "docker swarm init" or "docker swarm join" to connect this node to swarm and try again.

So, how can I create a network with a swarm cluster( without docker-machine and virtual box )? Currently, the swarm manager and worker nodes are running as docker containers.

Answer 1

Did you setup overlay networking with it's own etcd backend first? https://docs.docker.com/network/overlay-standalone.swarm/

Swarm "classic" is deprecated and replaced by docker swarm mode. Everything is harder in classic, including setting up overlay. I wouldn't recommend using it for anything new unless you had a hard requirement.

Answer 2

In swarm mode you run all commands at the swarm manager host. Same with creating networks, secrets, etc. You can find out the docker manager machine by: $docker node ls Manager host is marked with MANAGER STATUS:Leader. After creating the network on the manager all nodes on that swarm should see the network.

"I ran docker -H :4000 network create -d overlay test" Better to declare the network inside the stack yml file, for faster and easier deployment. you can create network and expose your ports at the yml file, no need to create them manually every time you run the stack. Add the following block under the docker service:

services:
...
#Network
   networks:
    - network-name-here
...
#Exposed ports:
  ports:
    - target: 4000 
      published: 4000

At the end of the yml file add the following block to declare the network, so its created every time you run $docker stack deploy:

networks:
  network-name-here:
   driver: overlay