Cannot access MySQL using default `docker run` command

[arencambre]

Per https://hub.docker.com/_/mysql, I can use docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:tag to start a MySQL instance. In my case, I used latest where tag was.

Adding a -p 3306:3306 switch has no effect, even thought that should work.

This does not work:

Per my Docker Desktop client, it is started:

It appears that it is not binding to its own port:

Here's a copy of the logs from Docker Desktop when I don't use the -p switch: mysql.log

Same log but when I do use the -p switch, which causes it to exit with an error code of 1: mysql_3306.log

The essentials of my network are running correctly and as expected, so I am at a loss to explain this. I am able to browse to the Drupal instance in the container that you can see is running above:

It is binding correctly:

[tianon]

Unfortunately, we don't have the bandwidth for providing deployment assistance here -- I would suggest trying a dedicated support forum, such as the Docker Community Slack, Server Fault, Unix & Linux, or Stack Overflow.

[arencambre]

Hi, I am not sure the issue is clear. The problem is with your documentation. If it says "do x to run MySQL", but x does not work, then you need to update your docs or advise that the provided instructions are incomplete (i.e., "Starting a MySQL instance is simple" misrepresents what needs to happen).

[yosifkit]

You must map the port if you want to access it from the Windows host and it needs to be before the image name, (i.e. a flag to the docker run, not a flag to mysqld):

$ # this passes the flag to docker run:
$ docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d -p 3306:3306 mysql:8

$ # this one won't work since it becomes a flag to mysqld:
$ docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:8 -p 3306:3306

Caveat is that in most Docker setups this will likely expose your database to the entire network on which your host resides. But you do not need the port if you only want other containers to have access, they can just hit the IP address of the container (and, on Linux, the host can too).

---

On a side note, you'll definitely want to look into Docker volumes if you want any of the data to persist longer than one docker run (https://github.com/docker-library/docs/tree/b23dd339992a0173a7e0db1a8ec4809b6cb0e64c/mysql#where-to-store-data).

[arencambre]

@yosifkit thank you. Through an interaction at (https://serverfault.com/questions/1121831/cannot-access-mysql-in-container-from-windows-host), I have determined the issue is with the order of the -d and -p switches.

This is what I originally used, and it does not work: docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mysql:latest -p 3306:3306

This works: docker run --name some-mysql -e MYSQL_ROOT_PASSWORD=my-secret-pw -p 3306:3306 -d mysql:latest

Both of these are simply switches on the docker run command, and the reference does not specify any meaning to the order they appear. I am not yet clear how to explain this.

[arencambre]

OK, now I see the whole problem. I had interpreted that the image name was part of the -d switch. In fact, the image is not referenced by a switch, and it needs to appear after all switches. My bad, and sorry for the false alarm.

n00b errors are fun. Stupid n00b!