我如何确保始终连接到相同的Docker容器？

Question

I have a little problem with really understanding this. When I start 3 containers in Docker they get 3 different IP-Addresses, that are assigned sequentially, I can address them from other containers and everything works fine.
But when I start a different container before those 3, the 3 get different IP-Addresses and the entire setup goes to hell.

I have been pestering Google for quite a while now, but I don't seem to find a proper (and not too complicated) solution to have one steady way to connect to a certain container. It's not that I want to assign the IP myself, just to tell the docker host something like "every time container X starts, assign the IP 172.17.0.X to it"
There must be some way in which the order in which I start up the containers doesnt matter, it can't be that I have to change my settings every other time I restart containers.

So some help here would be nice?
Some way in which I can assign IPs to a container or give it some sort of alias that I can address from another container.

Answer 1

I think that you should use hostname instead of IP Address in your Docker containers. And when you run Docker containers, you are able to use --link between the container. See https://docs.docker.com/v1.8/userguide/dockerlinks/#communication-across-links

In the new version, It is easy to connect the containers together in same network. See https://docs.docker.com/engine/userguide/networking/dockernetworks/

Answer 2

Connect from container to another container through ip it is not the "docker-way", so the really proper way is using of --link as posted Nguyen Sy Thanh Son .
As example:
docker run --name=db image1 docker run --name=app --link outernamedb:internalname image2 and then inside of app container use internalname:3306

But it will not work if you try to start app db , for that case there is kind a legal hack for docker higher than 1.11.
From docker official docks you can use --ip flag to set exact ip for container docker run --name=db --ip 172.17.0.90 image1 docker run --name=app --ip 172.17.0.91 image2 and then inside of app container use 172.17.0.90:3306

Answer 3

Use Docker Networks . Links are being deprecated and the IP address stuff is a craziness :)

$ docker network create my-net
$ docker run -d --net my-net --name container1 image1
$ docker run -d --net my-net --name container2 image2
$ docker exec -it container1 sh
# ping container2
PING container2 (172.21.0.3): 56 data bytes
64 bytes from 172.21.0.3: seq=0 ttl=64 time=0.073 ms
...

Answer 4

you can find some information on this post

How do I set up a DNS container inside docker-compose?

i hope this helped ;)