why I can't ping my docker container?

Question

I run a docker container, which is named "redis". I want to use the "redis" container redis service, but I can't ping the container!

As the picture shows, my "redis" container is IP address is 172.17.0.15, but I can't connect to it.

I want to use the redis services. What is wrong with my configuration?

Answer 1

Because you're not on the same network. Containers are started on their own network by default, separate to the host's network.

If you run:

docker run -it debian ping 172.17.0.15

You should find it works. Even better, you can link containers and refer to them by name:

$ docker run -d --name redis redis
$ docker run --link redis:redis redis redis-cli -h redis ping
PONG

If you really want to access redis from your host, just publish a port through to the host:

$ docker run -d -p 6379:6379 redis

You should now be able to reach it at localhost:6379 on the host.