ERROR 2005 (HY000): Unknown MySQL server host 'some-mysql' (0)

[pcantalupo]

I'm trying to follow instructions on this page to run docker mysql

$ docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql
c365f36e34cd5a580d380f09be3845e84a7a8a741b5a739062d976895d353fb6

$ docker ps | grep some-mysql
c365f36e34cd        mysql               "docker-entrypoint.s…"   27 seconds ago      Up 26 seconds       3306/tcp, 33060/tcp   some-mysql

$ docker inspect bridge | grep -B2 -A5 some-mysql
        "Containers": {
            "c365f36e34cd5a580d380f09be3845e84a7a8a741b5a739062d976895d353fb6": {
                "Name": "some-mysql",
                "EndpointID": "5edbd0af493cad5c8c69525576aab0db8472e7523668104c2b23299053ed9bd6",
                "MacAddress": "02:42:ac:11:00:03",
                "IPv4Address": "172.17.0.3/16",
                "IPv6Address": ""
            },

Then I'm trying to connect to MySQL from the MySQL command line client with your example code where I replaced some_network with bridge since that is the network some-mysql is on. However I get the following error...why?

$ docker run -it --network bridge --rm mysql mysql -hsome-mysql -u root -p
Enter password: 
ERROR 2005 (HY000): Unknown MySQL server host 'some-mysql' (0)

Thank you

[tianon]

Docker's built-in DNS doesn't apply on the default bridge network -- it has to be a custom/user-created network for Docker to provide DNS resolution of containers.

[pcantalupo]

Is it possible up update your documentation to make this clearer? Thank you

[wglambert]

The default bridge network behavior isn't directly related to the image so reproducing Docker's documentation seems unnecessary and out of scope

https://docs.docker.com/network/bridge/#differences-between-user-defined-bridges-and-the-default-bridge

Containers on the default bridge network can only access each other by IP addresses, unless you use the --link option, which is considered legacy. On a user-defined bridge network, containers can resolve each other by name or alias.

Going to close since this is resolved

[martinp999]

I agree with @pcantalupo - the documentation should say something like -

"To get up and running fast -

• docker network create mysql-net
• docker run --network mysql-net --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag
• docker run --network mysql-net -it --rm mysql:tag mysql -hsome-mysql -uroot -p
  "

[wglambert]

We were using --link in the images examples but changed it from the discussion in #545

docker-library/docs#1441

Ditch a lot of "--link" examples (using "--network some-network" instead to force users to do more homework)

[maaikez]

I agree with @pcantalupo - the documentation should say something like -
* docker network create mysql-net
* docker run --network mysql-net --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag
* docker run --network mysql-net -it --rm mysql:tag mysql -hsome-mysql -uroot -p

Would be great if this was added to the documentation.

[liranye]

@martinp999
using your advice I still get the following error:
ERROR 2003 (HY000): Can't connect to MySQL server on 'some-mysql' (113)

[liran@localhost ~]$ docker run --network mysql-net --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:latest
497ff8aa24ce904230170a51649df8eb96de638baec90ed3510ec3d420f7c7e6
[liran@localhost ~]$ docker container ls
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS                 NAMES
497ff8aa24ce        mysql:latest        "docker-entrypoint.s…"   9 seconds ago       Up 8 seconds        3306/tcp, 33060/tcp   some-mysql
[liran@localhost ~]$ docker run --network mysql-net -it --rm mysql:latest mysql -hsome-mysql -uroot -p
Enter password: 
ERROR 2003 (HY000): Can't connect to MySQL server on 'some-mysql' (113)
[liran@localhost ~]$ 

[martinp999]

Hi @liranye,

I copied your cli statements (with the addition of an initial docker network create mysql-net) and I got in no problems. The fact that you get asked for a password indicates that the network bridge is working fine. Did you use the correct db pswd (my-secret-pw)?

I am using docker 20.10.2, build 2291f61.

[cas--]

I encountered this error while quickly trying to setup mysql. I would expect the documentation to get me up and running not:

force users to do more homework

There is little hint that users need to actually create a network so this is leaving them completely in the dark. Also by the time they come to connect with client using --network option they will need to go back destroy server container and recreate it using custom network...

I am thinking that the next step after starting the server could be an exec command to help users quickly get connected:

docker exec -it some-mysql mysql -p

Otherwise at a minimum for the client instance the wording could be improved

- connected to the `some-network` Docker network
+ connected to `some-network`, a [user-defined Docker network](https://docs.docker.com/network/network-tutorial-standalone/#use-user-defined-bridge-networks)).