How to clone a docker stack on the same server-CodePudding

I want to practice using docker-compose. I have a tournament happening over the weekend and I want to set up 10 copies of the same web app on ONE server with urls like:

http://team1.example.com
http://team2.example.com
etc...
http://team10.example.com

There will be 10 teams in the tournament, and they will all go to their respective url http://team<your team number>.example.com via web browser, save some information to a database, and maybe even modify the code on the actual server.

So I built a simple nodejs app that simply writes data to a mongo database. Then I decided to set up two websites http://team1.example.com and http://team2.example.com. So I made this docker compose file:

version: '3'

services:
  api1:
    image: dockerjohn/tournament:latest
    environment:
      - DB=database1
    ports:
      - 80:3000
    networks:
      - net1
  db1:
    image: mongo:4.0.3
    container_name: database1
    networks:
      - net1
  api2:
    image: dockerjohn/tournament:latest
    environment:
      - DB=database2
    ports:
      - 81:3000
    networks:
      - net2
  db2:
    image: mongo:4.0.3
    container_name: database2
    networks:
      - net2

networks:
  net1:
  net2:

Then I installed apache web server to reverse proxy team 1 to port 80 and team 2 to port 81. This all works fine.

To set up the remaining teams 3 to 10, I have to duplicate the entries I have in my docker compose yml file and duplicate virtual host entries in apache.

My question: Is there a docker command that will let me clone each docker stack (team 1, team2, etc...) more easily without all this data entry? Do I need Kubernetes to do this?

CodePudding user response：

Kubernetes would be way easier to set this up. It can take care of the reverse proxy setup too if you install the nginx controller.

You could create a single Kubernetes manifest containing:

a mongodb deployment, service, persistent volume claim
a nodejs deployment, service

You can then apply this 10 times, each time using a different namespace:

kubectl -n team01 -f manifest.yaml
kubectl -n team02 -f manifest.yaml
kubectl -n team03 -f manifest.yaml
...

Of course, you would need 10 different ingress rules because you want 10 different domains, but that would be the only thing you need to copy-paste.

CodePudding user response：

I figured it out. There are options for docker called swarm and stack. First, I simplified my docker-compose.yml file to just this:

version: '3'

services:
  api:
    image: dockerjohn/tournament:latest
    environment:
      - DB=$DB
    ports:
      - $WEB_PORT:3000
    networks:
      - mynet
  db:
    image: mongo:4.0.3
    networks:
      - mynet


networks:
  mynet:

Then I ran these commands from the same folder as my docker-compose file like this

docker swarm init
DB=team1_db WEB_PORT=81 docker stack deploy -c docker-compose.yml team1
DB=team2_db WEB_PORT=82 docker stack deploy -c docker-compose.yml team2
DB=team3_db WEB_PORT=83 docker stack deploy -c docker-compose.yml team3
DB=team4_db WEB_PORT=84 docker stack deploy -c docker-compose.yml team4
DB=team5_db WEB_PORT=85 docker stack deploy -c docker-compose.yml team5
etc...

You have to structure the DB env variable as <stack name located at the end of my docker stack deploy command>_<job name in the docker-compose yaml file>.

Now I just need to find a way to simplify my apache set up so I don't have to duplicate so many vhost entries . I heard there's a docker image called Traefik which can do this reverse proxy. Maybe I'll try that out and update my answer after.