2.3.1 evqld

evqld, also known as the EventQL server, is the main server program. When the EventQL server starts, it listens for network connections and HTTP requests from client programs and executes inserts and queries on behalf of those clients.

The EventQL server can be run in two modes called "standalone mode" and "cluster mode".

In the standalone mode evqld runs as a standalone process on a single machine and has no further dependencies. The standalone mode is ideal for evaluating and development setups as it allows you to have a server up and running within seconds. To learn more about how to run EventQL in standalone mode, read the First Steps or Standalone pages.

In the cluster mode, many instances of the evqld binary are run on a number of machines. When running in cluster mode, the individual EventQL Server instances connect to a coordination service like Zookeeper.

The evqld program has some options that can be specified at startup. For a complete list of options, run this command:

$ evqld  --help

Usage: $ evqld [OPTIONS]

   -c, --config <file>       Load config from file
   -C name=value             Define a config value on the command line
   --standalone              Run in standalone mode
   --datadir <path>          Path to data directory
   --listen <host:port>      Listen on this address (default: localhost:9175)
   --daemonize               Daemonize the server
   --pidfile <file>          Write a PID file
   --loglevel <level>        Minimum log level (default: INFO)
   --[no]log_to_syslog       Do[n't] log to syslog
   --[no]log_to_stderr       Do[n't] log to stderr
   -?, --help                Display this help text and exit
   -v, --version             Display the version of this binary and exit

   $ evqld --standalone --datadir /var/evql
   $ evqld -c /etc/evqld.conf --daemonize --pidfile /run/evql.pid

The EventQL Server also optionally reads a set of configuration variables that affect its operation as it runs. Configuration variables can be set as command line flags or loaded from a configuration file. For more information on the support configuration variables check the Configuration page.