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ganeti-confd(8) Ganeti | Version @GANETI_VERSION@

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Name

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ganeti-confd - Ganeti conf daemon

Synopsis

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**ganeti-confd** [-f] [-d]

DESCRIPTION

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**ganeti-confd** is a daemon used to answer queries related to the

configuration of a Ganeti cluster.

For testing purposes, you can give the ``-f`` option and the

program won't detach from the running terminal.

Debug-level message can be activated by giving the ``-d`` option.

Logging to syslog, rather than its own log file, can be enabled by

passing in the ``--syslog`` option.

The **ganeti-confd** daemon listens to port 1814 UDP, on all interfaces,

by default. The port can be overridden by an entry the services database

(usually ``/etc/services``) or by passing the ``-p`` option.  The ``-b``

option can be used to specify the address to bind to (defaults to

``0.0.0.0``). The daemon also listens on a Unix socket

(``@LOCALSTATEDIR@/run/ganeti/socket/ganeti-query``) on which it exports

a ``Luxi`` endpoint, serving query operations only. Commands and tools

use this socket if the build-time option for split queries has been

enabled.

The daemon will refuse to start if the user and group do not match the

one defined at build time; this behaviour can be overridden by the

``--no-user-checks`` option.

ROLE

~~~~

The role of the conf daemon is to make sure we have a highly available

and very fast way to query cluster configuration values.  This daemon

is automatically active on all master candidates, and so has no single

point of failure. It communicates via UDP so each query can easily be

sent to multiple servers, and it answers queries from a cached copy of

the config it keeps in memory, so no disk access is required to get an

answer.

The config is reloaded from disk automatically when it changes, with a

rate limit of once per second.

If the conf daemon is stopped on all nodes, its clients won't be able

to get query answers.

COMMUNICATION PROTOCOL

~~~~~~~~~~~~~~~~~~~~~~

The confd protocol is an HMAC authenticated json-encoded custom

format, over UDP. A client library is provided to make it easy to

write software to query confd. More information can be found in the

Ganeti 2.1 design doc, and an example usage can be seen in the

(external) NBMA daemon for Ganeti.

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