Using the CLI Tool

The nanny command acts on the configuration of a service, by first checking any pre-launch requirements, starting it when those are OK, and then watching logs and other status indicators until it reaches a stable running state.

Use nanny --help to get a list of global options and sub-commands, nanny ‹command› --help for detailed help on a specific command and its options, and nanny help to get information like the paths to configuration files and plugin directories.

Performing Checks

While checking requirements is always done when launching a service, it can also be triggered explicitely by using the check sub-command. If any requirement isn’t satisfied, the return code will reflect that – use this together with the -q option to test them in scripts.

The --pre and --post options can be used to select which checks to perform, if neither is given, all checks are active.

Each check produces a result with the following attributes: ok (either true or false), name (the qualfied name of the check), comment (details on the requirement, e.g. a file system path), and diagnostics (error messages, output of a command that actually performed the check, …).

Unless the global option -q is used, check results are printed to the console; if you use -v, diagnostic information is included, which can help to hunt down the reason for a check failure. The available output formats are text (tabular output), tap (Perl’s Test Anything Protocol), and serialization into json, yaml, or csv. Use the --format option to select them, text is the default.


$ nanny -v check -f tap
not ok 1 FileSystem:exists /etc/cassandra/
ok 2 FileSystem:exists /etc/hosts
not ok 3 FileSystem:mounted /mnt/data
# [Errno 2] No such file or directory: '/mnt/data'
not ok 4 FileSystem:mounted /mnt/commitlog
# [Errno 2] No such file or directory: '/mnt/commitlog'
not ok 5 FileSystem:mounted /opt
# path resides in root file system
ok 6 FileSystem:mounted /home
ok 7 FileSystem:mounted /home/jhe
not ok 8 FileSystem:diskfree /home 70% 44GiB [46.9% 43.8GiB/104.6GiB free]
# violated 70% condition (46.9% 43.8GiB free)
# violated 44GiB condition (46.9% 43.8GiB free)
ok 9 Host:packages oracle-java8-jre | oracle-java8-installer
# oracle-java8-jre 8.45-1~ui1404+1 install ok installed
ok 10 Host:packages javaservicewrapper
# javaservicewrapper 3.5.22-1~ui1404+1 install ok installed
not ok 11 Host:packages jolokia-jvm-agent
# Command '[u'dpkg-query', u'-W', u'-f=${Package} ${Version} ${Status}', u'jolokia-jvm-agent']' returned non-zero exit status 1

Launching Services