3.5 KiB
Logical Architecture
Current architecture uses so-called "Metadata via Facter Extension" approach, inspired by blog posts self-classifying puppet nodes, pulling a list of hosts from mcollective for puppet, A Simple Puppet Function to Retrieve Information From the Stored Config DB, nodeless-puppet example.
In a nutshell, the Fuel deployment orchestration engine Astute manages OS
provisioning via Cobbler, and uses an MCollective plugin to distribute a
Facter facts file that defines node's role and other deployment
variables for Puppet. You can find a detailed breakdown of how this
works in the Sequence Diagrams </develop/sequence>.
Following components are involved in managing this process:
- Astute: deployment orchestrator, manages the Puppet cluster (via MCollective) and the Cobbler provisioning service (over XML-RPC)
- Naily: RPC consumer implementing communication between Nailgun and Astute over AMQP protocol
- Nailgun1: Web UI backend based on the web.py
framework, includes following sub-components:
- Nailgun DB: a relational database holding the current state all OpenStack clusters and provisioning tasks
- Data Model (api/models.py, fixtures/): the definition of NailgunDB using SQLAlchemy ORM
- REST API (api/handlers/): controller layer of the Web UI, receives REST requests from the JavaScript UI and routes them to other Nailgun components
- RPC Receiver (rpc/): handles AMQP messages from Astute
- Task Manager (task/): creates and tracks background tasks
- JavaScript UI (static/js/): Web UI frontend based on Twitter Bootcamp framework, communicates with Nailgun using REST API
In the current implementation the deployment business logic is spread between Nailgun (primarily in Task, Network, and Volume Manager components) and Astute. Going forward, all logic should be moved from Astute to Nailgun, and Astute should become a simple executor of tasks defined by Nailgun.
Communication paths between these components are illustrated on the Logical Architecture Diagram:
package "Master Node" { [JavaScript UI] package "Nailgun Backend" { package "SQL Database" <<Database>> { [Nailgun DB] } [Nailgun DB] --> [Data Model] [Data Model] <-- [REST API] [RPC Receiver] --> [Nailgun DB] } [Provisioner (Cobbler)] --> [DHCP, DNS, TFTP] [RPC Consumer (Naily)] --> [RPC Receiver] : AMQP [RPC Consumer (Naily)] --> [Orchestrator (Astute)] : AMQP [Orchestrator (Astute)] --> [MCollective] [Puppet Master] } package "Target Node" { [MCollective Agent] --> [Puppet] } actor Web_User actor CLI_User Web_User --> [JavaScript UI] CLI_User --> [REST API]
[JavaScript UI] --> [REST API]
[Orchestrator (Astute)] --> [Provisioner (Cobbler)] : XML-RPC
[MCollective] --> [MCollective Agent] [Puppet] --> [Puppet Master]
Footnotes
Not to be confused with Nailgun the Java CLI accelerator↩︎