Agent Package Signing

The creation of a signed agent package requires four certificates. The developer (creator) certificate is used to sign the agent code and allows the platform to verify that the agent code has not been modified since being distributed. The admin certificate is used for allowing the agent into a scope of influence. The initiator certificate is used when the agent is ready to be deployed into a specific platform. The platform certificate is used to sign the possibly modified data that an agent would like to carry with it during moving from platform to platform. All of these certificates must be signed by a “known” Certificate Authority (CA).

In order to facilitate the development of agents Volttron Resticted includes packaging commands for creating the platform CA as well as the CA signed certificates for use in the agent signing process.

When the Volttron Restricted package is installed on a platform the volttron-pkg command will be expanded to

usage: volttron-pkg [-h] [-l FILE] [-L FILE] [-q] [-v]

[–verboseness LEVEL] | {package,repackage,configure,create_ca,create_cert,sign,verify}

The additional (sub)commands:

  • create_ca - Creates a platform specific root CA. When this command is executed the user will be required to respond to prompts in order to fill out the certificate’s data.
  • create_cert - Allows the creation of a ca signed certificate. A type of certificate must be specified as (–creator | –admin | –initiator | –platform) and the name(–name) of the certificate may be specified. The name will be used as the filename for the certificate on the platform.
  • sign - Signs the agent package at the specified level.
  • (ALWAYS REQUIRED) Agent package to be signed.
  • (ALWAYS REQUIRED) Signing level must be specified as one of (–creator | –admin | –initiator | –platform) and must be presented in the correct order. In other words an admin cannot sign the package until the creator has signed it.
  • –contract (resource contract) a file containing the definition of the necessary agent resources needed to execute properly. This option is only available to the creator.
  • –config-file a file used to define custom configuration for the starting of agent on the platform. This option is available to the initiator.
  • –certs_dir Allows the specification of where the certificate store is located. If this is not specified the default certificate store will be used.
  • verify Allows the user to verify a package is valid.
  • package - The agent package to validate against.

Agent Signing Example Using the Listener Agent

If VOLTTRON Restricted is installed and the security features are enabled, all agents must be signed prior to launching them. The following steps will describe how to sign an agent and will use the Listener agent as an example. From a terminal, in the volttron directory (~/volttron), enter the following commands:

  1. Package the agent:

    volttron-pkg package examples/ListenerAgent

  2. Sign the agent as creator:

    volttron-pkg sign --creator --contract resource_contract ~/.volttron/packaged/listeneragent-3.0-py2-none-any.whl

  3. Sign the agent as admin:

    volttron-pkg sign --admin ~/.volttron/packaged/listeneragent-3.0-py2-none-any.whl

  4. Sign the agent as initiator:

    volttron-pkg sign --initiator --config-file examples/ListenerAgent/config ~/.volttron/packaged/listeneragent-3.0-py2-none-any.whl

  5. Set the configuration file:

    volttron-pkg configure ~/.volttron/packaged/listeneragent-3.0-py2-none-any.whl examples/ListenerAgent /config

  6. Install agent into platform (with the platform running):

    volttron-ctl install ~/.volttron/packaged/listeneragent-3.0-py2-none-any.whl

Upon successful completion of this command the terminal output will inform one of the install directory, the agent UUID (unique identifier for an agent, each instance of an agent will have a different UUID) and the agent name:

Installed ~/.volttron/packaged/weatheragent-3.0-py2-none-any.whl as  a9d67c55-7f58-4591-80af-3c1ff8a81740 listeneragent-3.0

Now the agent can be started, enter the following command to start the agent:

volttron-ctl start --name listeneragent-3.0


volttron-ctl start --uuid <UUID>

The previous steps document the signing of an agent using the Listener agent as an example. When deploying other agents the following parameters, used in the example, will need to be modified according to which agent you are signing and starting. The following is a brief description of the components of the commands in the signing example above:

  • examples/ListenerAgent - Path to agents top-level directory.
  • ~/.volttron/packaged/listeneragent-3.0-py2-none-any.whl - Path to the agent wheel (check the ~/.volttron/packaged directory after step 1 in this example to view the name of the wheel).
  • examples/ListenerAgent/config - Path to the agents json style configuration file (note this configuration file is named config).