How to get mysqld.sock be in the pod environment without a volume?

[DevDorrejo]

Hello,

I am trying to setup koha-community in a container for a library, but while trying to connect to the database while everything is in a pod, it will fail if try to connect with the next structure: mysql -h db_koha -u koha -p, When executed, it will fail asking for mysqld.socket.

So, how can i expose mysqld.socket to the pod?

i run mariadb + temporal ubuntu container.

Thank you.

[baude]

consider --share when creating the pod

[DevDorrejo]

thank for the reply and sorry for bothering you, but can you be a bit more clear pls, i read the man and find that with share is to delimit the namespaces:
(--share string A comma delimited list of kernel namespaces the pod will share (default "ipc,net,uts")

But what namespaces you refer which certain I ignore it's existence.

thank you.

[rhatdan]

If you want to share mysql from the host into the container, then you need to use a volume. If you want to have all containers within the Pod see the same mysql socket, then you have to place the socket on a shared volume.

[DevDorrejo]

The only way is adding this to the pod/continaer -v mysql_socket:/var/run/mysqld/mysqld.sock?

[eriksjolund]

Maybe some day in the future it will be possible to use the OpenFile= systemd directive?
I created a feature request for MariaDB Connector/C
See also

• support for systemd directive OpenFile= could be useful when connecting to a Unix socket in MariaDB Connector/C eriksjolund/mariadb-podman-socket-activation#10

[DevDorrejo]

That's nice, but would not work, because the rootfs share between containers.

[eriksjolund]

The Unix socket file does not need to be on the rootfs of the container. I wrote an example with a web server running on the host that is listening on Unix socket. A modified curl running in a container fetches a web page from that web server. It works because systemd on the host connects to the Unix socket. Then systemd, podman and conmon passes the file descriptor to the container via fork/exec inheritance.

See example:
https://github.com/eriksjolund/podman-OpenFile