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Maintenance socket

docs/operating-scylla/admin-tools/maintenance-socket.rst

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Maintenance socket

It enables interaction with the node through CQL protocol without authentication. It gives full-permission access. The maintenance socket is available by Unix domain socket with file permissions 755, thus it is not accessible from outside of the node and from other POSIX groups on the node. It is created before the node joins the cluster.

To set up the maintenance socket, use the maintenance-socket option when starting the node.

  • If set to ignore maintenance socket will not be created.
  • If set to workdir maintenance socket will be created in <node's workdir>/cql.m.
  • Otherwise maintenance socket will be created in the specified path.

The maintenance socket path has to satisfy following restrictions:

  • the path has to be shorter than 108 chars (due to linux limits),
  • a file or a directory cannot exists in this path.

Option maintenance-socket-group sets the owning group of the maintenance socket. If not set, the group will be the same as the user running the scylla node. The user running the scylla node has to be in the group specified by maintenance-socket-group option or have root privileges.

Usage

To access the maintenance socket, the user must belong to the same group as the socket's owner group. By default, the maintenance socket is owned by the user running the scylla node. It can be changed by maintenance-socket-group option. To connect to the maintenance socket, the user can add themselves to the 'scylla' group, run cqlsh as 'scylla', or adjust ownership via the maintenance-socket-group flag.

Connect to maintenance socket

With python driver ^^^^^^^^^^^^^^^^^^

.. code-block:: python

from cassandra.cluster import Cluster
from cassandra.connection import UnixSocketEndPoint
from cassandra.policies import WhiteListRoundRobinPolicy

socket = UnixSocketEndPoint("<node's workdir>/cql.m")
cluster = Cluster([socket],
                  # Driver tries to connect to other nodes in the cluster, so we need to filter them out.
                  load_balancing_policy=WhiteListRoundRobinPolicy([socket]))
session = cluster.connect()

With :doc:CQLSh</cql/cqlsh/> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: console

cqlsh <node's workdir>/cql.m