CODEWITHSUNDEEP
amazon-web-servicesdockeramazon-ec2
Mahiz
Mahiz

Reputation: 295

One App -> Run Multiple Docker Instances on Single Ec2

I have an application , say an api , running as docker container on ec2. As this container has dependency on the ec2 host ( port mapping) , i am unable to run more than one instance in a same machine.

I want to achieve a state where i have 5 hosts which are fronted with an elb and i should be able to run more than 1 instance of the container in all these hosts.

I am aware that i can achieve this state using ECS.

Can i do this with Ec2 , ELB and Docker?

-Thanks

Upvotes: 4

Views: 1595

Answers (1)

Tarun Lalwani
Tarun Lalwani

Reputation: 146630

There are multiple ways to do it

Use different port for each docker container

docker run -d -p 81:80 yourimage
docker run -d -p 82:80 yourimage
docker run -d -p 83:80 yourimage
docker run -d -p 84:80 yourimage
docker run -d -p 85:80 yourimage

And then you can put a nginx load balancer on port 80. See more details on http://nginx.org/en/docs/http/load_balancing.html

You need to use a config like below

http {
    upstream myapp1 {
        server 127.0.0.1:81;
        server 127.0.0.1:82;
        server 127.0.0.1:83;
        server 127.0.0.1:84;
        server 127.0.0.1:85;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://myapp1;
        }
    }
}

Use single node docker swarm manager

You can setup a single node docker swarm using below command

docker swarm init

And then on that machine run the below command

docker service create --name=myapp --replicase=5 -p 80:80 yourimage

This will create 5 load balanced container and publish them on port 80.

No ELB needed in both cases. And I doubt ELB works on same host + multi port scenario

Upvotes: 4

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