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Connecting to Docker Containers

I have been installing and exposing SSH on most of the containers I have deployed, which I know is wrong.

As I have been trying to do things in a more “devops” way I decided to do a little reading on how I can enter and leave running containers on my CentOS 7 instance without having to expose SSH or configure users.

This is when I came across nsenter & docker-enter. As you can see from the following instructions and terminal session installing nsenter and then using docker-enter to connect to a running container is a breeze;

docker run — rm jpetazzo/nsenter cat /nsenter > /tmp/nsenter<br>mv /tmp/nsenter /usr/local/bin/<br>chmod 755 /usr/local/bin/nsenter<br>nsenter -V<br>nsenter — help<br>curl -o /usr/local/bin/docker-enter <a href="https://raw.githubusercontent.com/jpetazzo/nsenter/master/docker-enter" target="_blank" data-href="https://raw.githubusercontent.com/jpetazzo/nsenter/master/docker-enter">https://raw.githubusercontent.com/jpetazzo/nsenter/master/docker-enter</a> <br>chmod 755 /usr/local/bin/docker-enter

Now you have installed nsenter and docker-enter you need to lauch a container to conect to;

docker run -d -p 3306:3306 — name testing russmckendrick/mariadb<br>docker logs testing<br>docker-enter testing # Enters the container, type exit to exit o_O<br>docker-enter testing ls -lha /var/lib/mysql/ # Lists the contents of /var/lib/mysql/<br>docker-enter testing ps -aux # Shows the running processes

You can view this process in the embedded terminal session below or on my asciinema profile

[embed]https://asciinema.org/a/11696[/embed]

Author

Russ McKendrick

Buys way too many vinyl records, writes a lot about Docker & loves orchestration. Works at @node4ltd / @n4stack has written for @PacktPublishing