Welcome to Octavia!
Octavia is an open source, operator-scale load balancing solution designed to work with OpenStack.
Octavia was born out of the Neutron LBaaS project. Its conception influenced the transformation of the Neutron LBaaS project, as Neutron LBaaS moved from version 1 to version 2. Starting with the Liberty release of OpenStack, Octavia has become the reference implementation for Neutron LBaaS version 2.
Octavia accomplishes its delivery of load balancing services by managing a fleet of virtual machines, containers, or bare metal servers—collectively known as amphorae— which it spins up on demand. This on-demand, horizontal scaling feature differentiates Octavia from other load balancing solutions, thereby making Octavia truly suited “for the cloud”.
Where Octavia fits into the OpenStack ecosystem¶
Load balancing is essential for enabling simple or automatic delivery scaling and availability. In turn, application delivery scaling and availability must be considered vital features of any cloud. Together, these facts imply that load balancing is a vital feature of any cloud.
Therefore, we consider Octavia to be as essential as Nova, Neutron, Glance or any other “core” project that enables the essential features of a modern OpenStack cloud.
In accomplishing its role, Octavia makes use of other OpenStack projects:
Nova - For managing amphora lifecycle and spinning up compute resources on demand.
Neutron - For network connectivity between amphorae, tenant environments, and external networks.
Barbican - For managing TLS certificates and credentials, when TLS session termination is configured on the amphorae.
Keystone - For authentication against the Octavia API, and for Octavia to authenticate with other OpenStack projects.
Glance - For storing the amphora virtual machine image.
Oslo - For communication between Octavia controller components, making Octavia work within the standard OpenStack framework and review system, and project code structure.
Taskflow - Is technically part of Oslo; however, Octavia makes extensive use of this job flow system when orchestrating back-end service configuration and management.
Octavia is designed to interact with the components listed previously. In each case, we’ve taken care to define this interaction through a driver interface. That way, external components can be swapped out with functionally-equivalent replacements— without having to restructure major components of Octavia. For example, if you use an SDN solution other than Neutron in your environment, it should be possible for you to write an Octavia networking driver for your SDN environment, which can be a drop-in replacement for the standard Neutron networking driver in Octavia.
As of Pike, it is recommended to run Octavia as a standalone load balancing solution. Neutron LBaaS is deprecated in the Queens release, and Octavia is its replacement. Whenever possible, operators are strongly advised to migrate to Octavia. For end-users, this transition should be relatively seamless, because Octavia supports the Neutron LBaaS v2 API and it has a similar CLI interface. Alternatively, if end-users cannot migrate on their side in the forseable future, operators could enable the experimental Octavia proxy plugin in Neutron LBaaS.
It is also possible to use Octavia as a Neutron LBaaS plugin, in the same way as any other vendor. You can think of Octavia as an “open source vendor” for Neutron LBaaS.
Octavia supports third-party vendor drivers just like Neutron LBaaS, and fully replaces Neutron LBaaS as the load balancing solution for OpenStack.
For further information on OpenStack Neutron LBaaS deprecation, please refer to https://wiki.openstack.org/wiki/Neutron/LBaaS/Deprecation.
Before you proceed further in this introduction, please note:
Experience shows that—within the subsegment of the IT industry that creates, deploys, and uses load balancing devices or services— terminology is often used inconsistently. To reduce confusion, the Octavia team has created a glossary of terms as they are defined and used within the context of the Octavia project and Neutron LBaaS version 2. This glossary is available here: Octavia Glossary
If you are familiar with Neutron LBaaS version 1 terms and usage, it is especially important for you to understand how the meanings of the terms “VIP,” “load balancer,” and “load balancing,” have changed in Neutron LBaaS version 2.
Our use of these terms should remain consistent with the Octavia Glossary throughout Octavia’s documentation, in discussions held by Octavia team members on public mailing lists, in IRC channels, and at conferences. To avoid misunderstandings, it’s a good idea to familiarize yourself with these glossary definitions.
A 10,000-foot overview of Octavia components¶
Octavia version 4.0 consists of the following major components:
amphorae - Amphorae are the individual virtual machines, containers, or bare metal servers that accomplish the delivery of load balancing services to tenant application environments. In Octavia version 0.8, the reference implementation of the amphorae image is an Ubuntu virtual machine running HAProxy.
controller - The Controller is the “brains” of Octavia. It consists of five sub-components, which are individual daemons. They can be run on separate back-end infrastructure if desired:
API Controller - As the name implies, this subcomponent runs Octavia’s API. It takes API requests, performs simple sanitizing on them, and ships them off to the controller worker over the Oslo messaging bus.
Controller Worker - This subcomponent takes sanitized API commands from the API controller and performs the actions necessary to fulfill the API request.
Health Manager - This subcomponent monitors individual amphorae to ensure they are up and running, and otherwise healthy. It also handles failover events if amphorae fail unexpectedly.
Housekeeping Manager - This subcomponent cleans up stale (deleted) database records and manages amphora certificate rotation.
Driver Agent - The driver agent receives status and statistics updates from provider drivers.
network - Octavia cannot accomplish what it does without manipulating the network environment. Amphorae are spun up with a network interface on the “load balancer network,” and they may also plug directly into tenant networks to reach back-end pool members, depending on how any given load balancing service is deployed by the tenant.
For a more complete description of Octavia’s components, please see the Octavia v0.5 Component Design document within this documentation repository.