When deploying a service, the charm you use will often support or even require specific configuration options to be set.
Juju provides tools to help manage these options and respond to changes over the lifetime of the service deployment. These options apply to the entire service, as opposed to only a specific unit or relation. The configuration can be modified by an administrator at deployment time or after the services are operational.
Each charm will have its own set of options and possible values. You can discover these in several ways:
- By running the
juju get <service>command.
- By viewing the charm in the charm store.
- By examining the config.yaml file in the charm itself.
Configuration values for a service can be set during deployment in several ways:
- by using a [yaml-formatted][yaml] file
- by passing options/values directly on the command line
- a combination of the above
All these methods use the
For example, upon investigation we discover that the Mediawiki charm allows us to set values for the 'name' of the wiki and the 'skin' to use. We can put these inside a configuration file.
mediawiki: name: Juju Wiki skin: monobook
Assuming the file is called
myconfig.yaml, the service can be deployed and
configured in this way:
juju deploy --config myconfig.yaml mediawiki
Warning: If the configuration file cannot be read or contains syntax errors or invalid options, an error message will be printed to this effect. However, the service will still be deployed .
To pass the options directly:
juju deploy --config name='Juju Wiki' --config skin='monobook'
A combination can also be used. If a duplication arises, the last-mentioned value gets used. For instance, below, the wiki will be assigned the name of 'Juju Wiki':
juju deploy --config name='Juju Wookie' --config myconfig.yaml
It is possible to set or change configuration of a service which is already deployed.
Before you set any of these options, you may want to check what current options
are already set, using the
juju get <service> command. For example:
juju get mediawiki
Should return something like this:
charm: mediawiki service: mediawiki settings: admins: default: true description: Admin users to create, user:pass type: string value: null debug: default: true description: turn on debugging features of mediawiki type: boolean value: false logo: default: true description: URL to fetch logo from type: string value: null name: default: true description: The name, or Title of the Wiki type: string value: Please set name of wiki skin: default: true description: skin for the Wiki type: string value: vector
You can set the options using the
juju set <service>, specifying
multiple key=value pairs if necessary:
juju set mediawiki skin=monoblock name='Juju Wiki'
Setting an option back to its default value is done using the
followed by the service and the respective options:
juju unset mediawiki admins name