root / man / ganeti-confd.rst @ 1a182390
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ganeti-confd(8) Ganeti | Version @GANETI_VERSION@ |
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================================================= |
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Name |
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---- |
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ganeti-confd - Ganeti conf daemon |
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Synopsis |
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-------- |
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**ganeti-confd** [-f] [-d] |
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DESCRIPTION |
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----------- |
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**ganeti-confd** is a daemon used to answer queries related to the |
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configuration of a Ganeti cluster. |
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For testing purposes, you can give the ``-f`` option and the |
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program won't detach from the running terminal. |
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Debug-level message can be activated by giving the ``-d`` option. |
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Logging to syslog, rather than its own log file, can be enabled by |
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passing in the ``--syslog`` option. |
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The **ganeti-confd** daemon listens to port 1814 UDP, on all interfaces, |
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by default. The port can be overridden by an entry the services database |
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(usually ``/etc/services``) or by passing the ``-p`` option. The ``-b`` |
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option can be used to specify the address to bind to (defaults to |
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``0.0.0.0``). |
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The daemon will refuse to start if the user and group do not match the |
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one defined at build time; this behaviour can be overridden by the |
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``--no-user-checks`` option. |
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ROLE |
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~~~~ |
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The role of the conf daemon is to make sure we have a highly available |
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and very fast way to query cluster configuration values. This daemon |
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is automatically active on all master candidates, and so has no single |
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point of failure. It communicates via UDP so each query can easily be |
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sent to multiple servers, and it answers queries from a cached copy of |
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the config it keeps in memory, so no disk access is required to get an |
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answer. |
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The config is reloaded from disk automatically when it changes, with a |
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rate limit of once per second. |
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If the conf daemon is stopped on all nodes, its clients won't be able |
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to get query answers. |
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COMMUNICATION PROTOCOL |
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~~~~~~~~~~~~~~~~~~~~~~ |
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The confd protocol is an HMAC authenticated json-encoded custom |
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format, over UDP. A client library is provided to make it easy to |
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write software to query confd. More information can be found in the |
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Ganeti 2.1 design doc, and an example usage can be seen in the |
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(external) NBMA daemon for Ganeti. |
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.. vim: set textwidth=72 : |
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