ganeti-confd - Ganeti conf daemon
ganeti-confd [-f] [-d]
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 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.
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.
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.