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Knot-Resolver Administration
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Instances
=========

The kresd instances can be generated on the fly with the help of the template unit file under systemd. Simultaneously with the creation of the service a control-socket is created.

For example: systemctl start kresd@foo.service

When the instances should be persistent these commands can be used:

.. code-block:: bash

    systemctl enable --now kresd@1.service
    systemctl enable --now kresd-control@1.socket

To manage all kresd instances a slice can be used. When changing something in the configuration file a restart of the slice is the recommended way to apply the changes. Furthermore when stopping the slice serivce all instances are going down (Not the same behaviour as restart). When the slice is taken down no instance comes up automatically even if a query comes in.

.. code-block:: bash

    systemctl status system-kresd.slice
    systemctl stop system-kresd.slice
    systemctl start system-kresd.slice

Start all kresd instances at the same time.

.. code-block:: bash

    systemctl --all start kresd@*.service

Start all kresd instances explicitly.

.. code-block:: bash

    systemctl start kresd@{1,2,3,4}.service

A stopped kresd instance assumed that the slice is still running comes up automatically when a query comes in since it is a socket activated service.

Debugging
=========

For debugging two methods are possible:
        - With restart
        - without restart

With restart
------------

To enable verbosity add this line in the configuration file and restart (reload is not possible) the kresd slice:

.. code-block:: bash

    verbose(true)


Without restart
---------------

To enable verbosity on a running kresd instances a connection to a control socket is necessary. This command have to be executed on every control socket because it is not clear which one is responding a query.

.. code-block:: bash

    socat - UNIX-CONNECT:/run/knot-resolver/control@${socket}
    $ verbose true

Clear cache
-----------

To clear the cache do the following. It is enough to do it only on one control socket because the cache is shared among them.

.. code-block:: bash

    socat - UNIX-CONNECT:/run/knot-resolver/control@${socket}
    $ cache.clear()