Configuration Reference

TODO

Configuration File Structure

Configuration files consist of sections that start with a [section-name] line, with an (unnamed) global section before the named ones. Nesting sub-sections into outer sections is achieved by adding more square brackets. See ConfigObj Files for more details.

Each section holds a list of key/value pairs.

Note

Later versions will offer alternative formats like YAML, as long as they’re able to represent this nested structure of sections and key/value pairs.

Main Configuration Files

Configuration files are expected at the locations as shown by the nanny help command, on a Linux system that is:

/etc/bootils/nanny.conf
/etc/bootils/nanny.d/*.conf
~/.config/bootils/nanny.conf

If you define the NANNY_CONFIG environment variable with additional files, those will be appended to the default list – try this command to see for yourself:

NANNY_CONFIG=/tmp/foo.conf:/tmp/bar.conf nanny help

Configuration files are merged in the given order, i.e. keys that appear in files further down the list shadow those in files read earlier. This allows you to provide general settings in the default files, and then modify and extend them for a specific service.

Common usage patterns are to have everything in /etc/bootils/nanny.conf if you only ever run a single service (say, in a Docker container), and use the conf.d directory for snippets of global configuration added by packages. If you run several services on one machine, keep nanny.conf clear of settings specific to any service, and use nanny.d/‹service›.conf files for those. In the service-specific files, be sure to qualify your top-level sections with the service name, e.g. [‹service›:pre-check].

Built-in Plugins

FileSystem

This plugin allows to check that a certain path exists, is executable, or is mounted (i.e. not part of the root file-system). You can also check for free space of the volume of a given path using diskfree.

All these attributes take a multi-line list of paths to check, diskfree also expects a percentage or size threshold of minimal free space. If both a percentage and a size is given, each must be satisfied for the check to be OK.

Example:

[pre-check]

[[FileSystem]]

exists = """
    /etc/cassandra/jolokia-config.properties
    /etc/hosts
"""

executable = """
    /bin/bash
"""

mounted = """
    /mnt/data
    /mnt/commitlog
    /opt
    /home
"""

diskfree = """
    /home 5% 42GiB
"""

Host

With the Host plugin, you can ensure that essential packages were indeed installed by your configuration management tool. This provides explicit diagnostics (unlike e.g. a command not found for some missing tool), and avoids errors that might only appear when a service tries to access an optional component that was not installed.

Example:

[pre-check]

[[Host]]
packages = """
    oracle-java8-jre | oracle-java8-installer
    service-wrapper
    jolokia-jvm-agent
"""

Network

The network plugin is able to check if all ports and addresses, that your server is going to use, are not already bound.

Example (short-hand notation):

[pre-check]

[[Network]]
ports = 80, 8081

Example (verbose):

[pre-check]

[[Network]]

[[[http]]]
port = 80
family = tcp
address = 0.0.0.0

[[[jmx_port]]]
port = 6379
family = tcp
address = 127.0.0.1