ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services.
Space separated list of extra deb packages to install.
Four letter words to whitelist.
List of signing keys for install_sources package sources, per charmhelpers standard format (a yaml list of strings encoded as a string). The keys should be the full ASCII armoured GPG public keys. While GPG key ids are also supported and looked up on a keyserver, operators should be aware that this mechanism is insecure. null can be used if a standard package signing key is used that will already be installed on the machine, and for PPA sources where the package signing key is securely retrieved from Launchpad.
List of extra apt sources, per charm-helpers standard format (a yaml list of strings encoded as a string). Each source may be either a line that can be added directly to sources.list(5), or in the form ppa:<user>/<ppa-name> for adding Personal Package Archives, or a distribution component to enable.
The status of service-affecting packages will be set to this value in the dpkg database. Valid values are "install" and "hold".
Enable standalone for development/singleton deploys.