maintenance socket: provide a default path

[piodul]

The maintenance socket, introduced in #16172, provides a CQL interface through a Unix socket. Its intention is to allow administrative access.

However, the socket is not enabled by default. Initially, we wanted to have a default path but it was decided otherwise on the PR (discussion starts here: #16172 (comment)). We would like to revisit this decision.

One of the reasons that we want to reconsider is schema backup for Scylla Manager. Until now, SM has been saving sstables of the schema tables as a way to backup schema, but this method doesn't work with raft-based schema. We would like it to switch to using DESCRIBE SCHEMA WITH INTERNALS command via maintenance socket. However, because the maintenance socket is not enabled by default, the switch to the new method is not seamless as it requires additional configuration changes from the users.

[kbr-scylla]

Due to the SM backup issue, marking this as release blocker. (@mykaul please review the decision.)

[gleb-cloudius]

Why do you have to use maintenance socket as opposite to regular connection?

[piodul]

AFAIK regular connections may require authentication while the maintenance socket does not. Providing CQL credentials for Scylla Manager is optional.

[mykaul]

AFAIK regular connections may require authentication while the maintenance socket does not. Providing CQL credentials for Scylla Manager is optional.

I personally would make it mandatory (@tzach - unsure if we reached a decision here).

@piodul - is there a patch for this? (I know we are still waiting for gocql to support this!)

[piodul]

I personally would make it mandatory (@tzach - unsure if we reached a decision here).

@piodul - is there a patch for this? (I know we are still waiting for gocql to support this!)

@mykaul Do you mean making it mandatory to provide CQL credentials for SM? AFAIK if SM uses the Unix socket then credentials will not be mandatory.

As for the support for the Unix socket in SM, there is the issue scylladb/scylla-manager#3831 but no patches yet.

[mykaul]

@piodul - patch to providing a default path to the maint. socket.

[piodul]

@piodul - patch to providing a default path to the maint. socket.

It looks like there isn't one yet.
Just to be clear - this task is currently in @kbr-scylla's team scope, core-backend is not working on this.

[tzach]

Lets assume Manager / Admin has premission during restore / backup

[kbr-scylla]

Taking off release blocker label then.