What is it?
The Red Hat Enterprise Linux OpenStack Platform director is a toolset that was produced by Red Hat. It is made for installing and managing a complete OpenStack environment. Red Hat Director is primarily based on the OpenStack project TripleO. TripleO is an abbreviation for “OpenStack-On-OpenStack”. This project takes advantage of OpenStack components to install a fully operational OpenStack environment. This includes new OpenStack components that provision and control bare metal systems to use as OpenStack nodes. This in turn provides a more simple method for installing a complete Red Hat Enterprise Linux OpenStack Platform environment that is both lean and robust.
Our experience is that Red Hat Director is a great solution for most use cases. But also can be tricky for some specific use cases; for example when Lifecycle Management is an important part of the business model.
Why does it exist?
An OpenStack deployment can be known to be a bit challenging. That’s mainly because deployment includes a lot more than just getting the software installed. For instance, it’s about architecting your platform to use existing infrastructure as well as planning for future scalability and flexibility. OpenStack is designed to be a massively scalable platform, with distributed components on a shared message bus and database backend. Our experience with OpenStack, as well as with other open source solutions is that when you configurere it properly you won’t be needing much troubleshooting or maintenance to keep it going.
How does it work?
The Red Hat Enterprise Linux OpenStack Platform director uses two main concepts: an Undercloud and an Overcloud.
The Undercloud is the main director node. It is a single-system OpenStack installation that includes components for provisioning and managing the OpenStack nodes that form your OpenStack environment (the Overcloud). To get the OpenStack Overcloud provisioned the following components are used in the Undercloud:
· Ironic and Nova for managing bare metal nodes
· Neutron for controlling the network of bare metal nodes
· Glance for storing images that are written to the bare metal machines.
· Heat and Puppet for providing the orchestration and configuration of nodes.
· Ceilometer for monitoring and data collection.
· Keystone for authentication and authorization for the directors’ components.
· MariaDB for database backend for the director.
· RabbitMQ for messaging queue.
The Overcloud is basically the cloud which executes all the typical cloud workloads. This means that the Overcloud consists of the controller nodes for providing network, administration and high availability of the cloud, Compute nodes for the delivery of compute power and Storage nodes (Ceph, Cinder and Swift).
Red Hat Director ships with a number of validation tools to verify that any user-provided templates are correct (like the networking files), that also be useful when performing updates or upgrades. For that, we leverage Ansible in the upgrade sanity check scripts. Once deployed you can automatically test a deployed overcloud using Director’s Tempest toolset. Tempest verifies that the overcloud is working as expected with hundreds of end-to-end tests, in a way that it conforms to the upstream API specification. Red Hat is committed to shipping the standard API specification and not breaking update and upgrade paths for customers and therefore providing an automated mechanism for compatibility is of paramount importance.
In terms of the deployment architecture itself, Red Hat has built a highly available reference architecture containing our recommended practices for availability, resiliency, and scalability. The default Heat templates as shipped within Director have been engineered with this reference architecture in-mind, and therefore a customer deploying OpenStack with Director can leverage their extensive work with customers and partners to provide maximum stability, reliability, and security features for their platform. For instance, Red Hat Director can deploy SSL/TLS based OpenStack endpoints for better security via encrypted communications.
At Fairbanks and 42on we not only love Linux, OpenStack and Kubernetes but off course also Ceph. Because of this we are happy that the majority of the production customers are using Ceph combined with OpenStack. That’s why Ceph is the default storage backend within the Red Hat Director, and automatically deploys Ceph monitors on controller nodes, and Ceph OSDs on dedicated storage nodes. Alternatively, it can connect the OpenStack installation to an existing Ceph cluster. The Red Hat Director supports a wide variety of Ceph configurations.
Source: Red Hat