Provisioning System Sample Clauses

Provisioning System. The PARTHENOS e-infrastructure is currently comprising 212 servers and one of its core ambitions in designing it was the reduction of the deployment, operation, and maintenance costs. To achieve this ambition a key aspect was to automatize the configuration and management of servers, combining multi-servers software deployment, supporting ad hoc task execution, and configuration management. Ansible is a free-software platform allowing configuration of servers according to idempotence. Idempotency is basically based on the description of what state is required on a server and Ansible figures out how to get to that state. This approach is opposite to other approaches that require specification of what to run on a server and how to run it. This allows to reduce drastically the costs of operations since it becomes possible to run Ansible plays over and over and it does the right thing according to the status of the server instead of repeating commands and configurations. Ansible is really useful for repeatedly setting up servers in the Cloud which need to be set up the same way. In order to exploit Ansible in the PARTHENOS e-infrastructure, it was needed to define a number of resources and configuration scripts that then are exploited by Ansible to perform the activities • inventories - list of servers to configure and maintain • playbooks - collection of plays, or simply a collection of roles for a 1-play playbook • plays - a collection of roles • roles - generally, one service (like postgres or nginx) • tasks - a command that Ansible runs via its modules, like a task for installing a package via apt-get • handlers - like tasks that get called when other tasks request them via notifications. Typically used to restart services. • host vars - variables that apply to one collection of hosts • modules - provided by Ansible to do things like configure MySQL (mysql module), install via apt-get (apt module), copy over files (file module), add users (user module). Overall, to manage the PARTHENOS e-infrastructure 197 roles have been defined.