# Extending Docker Configuration

Remco (opens new window) is used to generate the Rundeck configuration files from templates. It supports different key/value sources such as vault, etcd, and dynamodb. All configuration backends are combined into a unified keyspace. This allows storing parts of the configuration space in different backends. The default configuration uses environment variables.

Extending the configuration involves building a derived image with additional template files.

# Configuration Layout

├── Dockerfile
├── remco
   ├── config.toml
   ├── resources.d
   │   ├── artifact-repositories-private.yaml.toml
   │   ├── framework.properties.toml
   │   ├── grails-config.properties.toml
   └── templates
       ├── artifact-repositories-private.yaml
       ├── framework.properties
       ├── grails-config.properties
       ├── jaas-loginmodule.conf
       ├── log4j2.properties

The above is an abridged layout of the remco configuration files in the Rundeck image source directory. The three primary components for the configuration system are:

  • config.toml Where the config backends and resource includes are configured
  • remco/resources.d Directory that includes the resources files declaring the templates
  • remco/templates Directory where the templates are stored

# Template Resources

    src         = "${REMCO_TEMPLATE_DIR}/framework.properties"
    dst         = "${RUNDECK_HOME}/etc/framework.properties"
    mode        = "0644"

The template resource files declare:

  • src The source template file
  • dst Where the template will be rendered on disk
  • mode The file mode for the created file

# Config Merging

    src         = "${REMCO_TEMPLATE_DIR}/rundeck-config-features.properties"
    dst         = "${REMCO_TMP_DIR}/rundeck-config/rundeck-config-features.properties"
    mode        = "0644"

In the above example the destination is the special temporary directory ${REMCO_TMP_DIR}/rundeck-config/. All files in this directory will be merged into rundeck-config.properties before Rundeck starts.

# Special Destination Directories

All template files rendered into special destination directories are merged into common Rundeck configuration files before Rundeck starts. The special template destination directories are:

  • ${REMCO_TMP_DIR}/rundeck-config/ -> rundeck-config.properties
  • ${REMCO_TMP_DIR}/framework/ -> framework.properties

# Extending Configuration

Extending the configuration by building a new Docker image derived from the Rundeck image is a snap. The following example is taken from the Docker Zoo Config Exhibit (opens new window).

Starting with the following layout:

├── docker-compose.yml
├── Dockerfile
├── README.md
└── remco
    ├── resources.d
    │   └── plugin-http-tours-framework.properties.toml
    └── templates
        └── plugin-http-tours-framework.properties

The plugin-http-tours-framework.properties.toml file contents are:

    src         = "${REMCO_TEMPLATE_DIR}/plugin-http-tours-framework.properties"
    dst         = "${REMCO_TMP_DIR}/framework/plugin-http-tours-framework.properties"
    mode        = "0644"

This file declares the input template source and an output destination to the special directory ${REMCO_TMP_DIR}/framework/. This contents of the rendered template will be merged into framework.properties at startup.

The template contents are as follows:

{% if exists("/rundeck/tour/endpoint") %}

framework.plugin.TourLoader.httptours.tourEndpoint={{ getv("/rundeck/tour/endpoint") }}
framework.plugin.TourLoader.httptours.tourManifestName={{ getv("/rundeck/tour/manifest","tour-manifest.json") }}
framework.plugin.TourLoader.httptours.toursSubpath={{ getv("/rundeck/tour/subpath","tours") }}

{% endif %}

This template adds configuration for a new plugin.

The following line from the Dockerfile includes the new remco configurations in the derived Docker image:

COPY --chown=rundeck:root remco /etc/remco
Last Updated: 9/24/2020, 12:18:36 AM