Imply ships with a supervise command that manages service lifecycles and console logs. It is configured through a single configuration file per machine. Each machine can potentially start many services. For example, when you run the command:
bin/supervise -c conf/supervise/master-with-zk.conf
This tells supervise to use the file
conf/supervise/master-with-zk.conf to select which services
By default, the supervise program runs in the foreground. You can run supervision in the
background, if you want, by adding the
bin/supervise -c conf/supervise/master-with-zk.conf --daemon
You can restart an individual service using its name. For example, to restart the zk service,
bin/service --restart zk from the distribution.
To shut down all services on a machine, kill the supervise process (CTRL-C or
both work) or run the command
bin/service --down from the distribution.
By default, logs are written to
var/sv/<service>/current in the distribution. You can write these
files to any location you want by passing the
-d <directory> argument to
For added convenience, you can also tail log files by running
bin/service --tail <service>.
On MacOS and Linux, logs are automatically rotated using the included logger program. On
other platforms, to prevent log files from growing forever, you can periodically truncate the
truncate -s 0 <logfile>.
You can modify the provided supervision files or create new files of your own. There are two kinds of lines in supervision files:
:verify some-program will run some-program on startup. If the program exits successfully,
supervise will continue. Otherwise, supervise will exit.
foo some-program will supervise a service named foo by running the program some-program. If
the program exits, supervise will start it back up. Its console logs will be logged to a file
When updating an Imply cluster, you should follow the typical procedure for a Druid Rolling Update. If you have deployed your cluster with the Master, Query, and Data server configuration, then take note of the following: