accessing a docker container from another container

Question

i created two docker containers based on two different images. one of db and another for webserver. both containers are running on my mac osx.

i can access db container from host machine and same way can access webserver from host machine.

however, how do i access db connection from webserver?

the way i started db container is

docker run --name oracle-db -p 1521:1521 -p 5501:5500 oracle/database:12.1.0.2-ee

I started wls container as

docker run --name oracle-wls -p 7001:7001 wls-image:latest

I can access db on host by connecting to

sqlplus scott/welcome1@//localhost:1521/ORCLCDB

I can access wls on host as

http://localhost:7001/console

Answer 1

It's easy. If you have two or more running container, complete next steps:

docker network create myNetwork
docker network connect myNetwork web1
docker network connect myNetwork web2

Now you connect from web1 to web2 container or the other way round.

Use the internal network IP addresses which you can find by running:

docker network inspect myNetwork

Note that only internal IP addresses and ports are accessible to the containers connected by the network bridge.

So for example assuming that web1 container was started with: docker run -p 80:8888 web1 (meaning that its server is running on port 8888 internally), and inspecting myNetwork shows that web1's IP is 172.0.0.2, you can connect from web2 to web1 using curl 172.0.0.2:8888).