06_names.md

Docker Lab: Names

Previously in the lab...

Question: Where do these strange names come from?

Answer: Docker (what a surprise!)... Beside the CONTAINER_ID the NAME is a unique identifier for a container.

Naming a Container

Unlike the CONTAINER_ID the NAME is something we can manipulate. The name is handy not only for starting/connecting/stopping/destroying a container but also for the networking (which comes later in the lab).

To do so you have to add a parameter in the run command of Docker

docker run --name mariadb-container -e MYSQL_ROOT_PASSWORD=my-secret-pw -d mariadb

As always, to check if this has really worked out look at the container list

$ docker container ls
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
6f08ac657320        mariadb             "docker-entrypoint..."   58 seconds ago      Up 57 seconds       3306/tcp            mariadb-container
699e82ed8f1f        mariadb             "docker-entrypoint..."   24 minutes ago      Up 24 minutes       3306/tcp            jolly_bardeen

If you want to access your DB server there are two ways:

1. Using docker exec -it mariadb-container bash This will connect you into the remote bash shell from where you can connect to the server via mysql -uroot -pmy-secret-pw.

2. Using a local mysqlclient This is a bit tricky. First you have to find out the IP address of your docker container. Therefore use this command:

$ docker inspect mariadb-container
[
    {
        "Id": "6f08ac657320f279a9193728905f6f18d74f72d2c5dea97a9ffc76fb7e216c59",
        "Created": "2018-05-31T06:37:18.180716875Z",
        "Path": "docker-entrypoint.sh",
        "Args": [
            "mysqld"
        ],

...

        "NetworkSettings": {
            "Bridge": "",
            "SandboxID": "5a244dfe119b4211326ae2afb7b4331cba026df3b9b0b535c619606a8fd68a61",
            "HairpinMode": false,
            "LinkLocalIPv6Address": "",
            "LinkLocalIPv6PrefixLen": 0,
            "Ports": {
                "3306/tcp": null
            },
            "SandboxKey": "/var/run/docker/netns/5a244dfe119b",
            "SecondaryIPAddresses": null,
            "SecondaryIPv6Addresses": null,
            "EndpointID": "6dcdf9ed5c90c9fbf5eee5253a7642efff861603c079b0cba17111cb5c3e2514",
            "Gateway": "172.17.0.1",
            "GlobalIPv6Address": "",
            "GlobalIPv6PrefixLen": 0,
            "IPAddress": "172.17.0.2",
            "IPPrefixLen": 16,
            "IPv6Gateway": "",
            "MacAddress": "02:42:ac:11:00:02",
            "Networks": {
                "bridge": {
                    "IPAMConfig": null,
                    "Links": null,
                    "Aliases": null,
                    "NetworkID": "4b12e50d081a1d103918e742503b0d52f05c50daf35c4d07d3bd7cd53fe75a79",
                    "EndpointID": "6dcdf9ed5c90c9fbf5eee5253a7642efff861603c079b0cba17111cb5c3e2514",
                    "Gateway": "172.17.0.1",
                    "IPAddress": "172.17.0.2",
                    "IPPrefixLen": 16,
                    "IPv6Gateway": "",
                    "GlobalIPv6Address": "",
                    "GlobalIPv6PrefixLen": 0,
                    "MacAddress": "02:42:ac:11:00:02",
                    "DriverOpts": null
                }
            }
        }
    }
]

In the last section (NetworkSettings) you will find the IPAddress for your container. In this example it's 172.17.0.2. Once you have the IP you can connect with the command mysql -h172.17.0.2 -uroot -p (use password from run command)

Note: The mysql client must be installed on your computer. On Windows, you can use the binary from the ZIP archive at https://dev.mysql.com/downloads/mysql/.

Question: I have a container with a database server running. But when I remove the container, what happens to my data?

Let's find out in... the next lab!

← Deleting Container | Working with Volumes →