Explanation

Architecture Overview

ctcontroller is made up of two main subcomponents:

1. The Provisioner:
   1. TACC provisioner
   2. Chameleon provisioner
2. The Application Manager:
   1. Camera Traps controller

The provisioner handles the provisioning and deprovisioning of hardware and currently supports two sites: Chameleon Cloud and bare metal nodes at TACC. It can be extended to other sites by defining a new subclass of Provisioner.

The Application Controller handles the setup, running, shutting down, and cleaning up of the application that was provisioned by the Provisioner. It currently only supports the Camera Traps application but can be extended to other applications by defining a new class.

Control Variables

ctcontroller accepts the following environment variables to be defined at runtime:

Variable	Description	Required
CT_CONTROLLER_NUM_NODES	number of nodes that will be provisioned	Yes
CT_CONTROLLER_TARGET_SITE	site where the nodes will be provisioned	Yes
CT_CONTROLLER_NODE_TYPE	identifier of the type of node that will be provisioned	Yes
CT_CONTROLLER_GPU	boolean which tells the provisioner if the node needs to have a GPU and the Application Controller needs to run the application on the GPU	Yes
CT_CONTROLLER_CONFIG_PATH	path to a config file	Yes
CT_CONTROLLER_MODEL	model used by the application	No
CT_CONTROLLER_INPUT	input images into the application	No
CT_CONTROLLER_SSH_KEY	path to the ssh key	No
CT_CONTROLLER_KEY_NAME	name of the ssh key (needed for OpenStack/Chameleon)	No
CT_CONTROLLER_CT_VERSION	version of the application to be run	No
CT_CONTROLLER_TARGET_USER	username to be used on target system	No
CT_CONTROLLER_OUTPUT_DIR	path to output directory	No
CT_CONTROLLER_JOB_ID	unique job ID to be used for provisioning hardware	No
CT_CONTROLLER_ADVANCED_APP_VARS	variables to be passed to application controller	No

Configuration File

The path to the configuration file is specified through the environment variable CT_CONTROLLER_CONFIG_PATH. ctcontroller expects this file to be a YAML file. sample_config.yml is a sample config file. Configuration files can be used to specify target host nodes to be provisioned, service account credentials, and authorized users.

The configuration file consists of three parts:

1. A description of the systems that can be accessed. Each system is given a unique identifier and contains the following attributes:
   1. Name, which expects a string corresponding to an identifier to for the ssh key for the system
   2. Path, which contains the path to the ssh key for the system
   3. Hosts, which is a dictionary whose keys are a hardware type and the values are lists of valid IP addresses for that host and the username on those hosts. For instance, {'hardware_type': [{'IP': ip_address1, 'Username': username1}, {'IP': ip_address2, 'Username: username2}]} would be a valid value for the Hosts attribute.
2. A list of authenticated users. The key is Users and authorized users must be a list
3. Advanced settings. The key is Settings and available settings are:
   1. AuthenticateUsers=True|False.