charm-specs/specs/train/implemented/charm-openstack-ovn.rst

OVN

OVN provides open source network virtualization for Open vSwitch (OVS):

• Logical switches
• IPv4 and IPv6 logical routers
• L2/L3/L4 ACLs (Security Groups)
• Multiple tunnel overlays (Geneve, STT and VXLAN)
• Logical L4 load-balancing
• TOR-based L2 logical-physical gateways (VTEP)
• Software-based L2/L3 logical-physical gateways

OVN integration components exists for OpenStack Neutron, Kubernetes and others.

Problem Description

There is currently no charms available that lets you easily deploy the services required to make use of OVN.

This will also benefit OPNFV's JOID installer in providing another scenario in its deployment.

Proposed Change

Implement new reactive charms that adds support for deploying OVN and integration with OpenStack.

Alternatives

None

Implementation

The implementation consists of the following charms:

• ovn-central
  • Principal charm that deploys ovn-northd, the OVN central control daemon, and ovsdb-server, the Open vSwitch Database (OVSDB).
  • The ovn-northd daemon is responsible for translating the high-level OVN configuration into logical configuration consumable by daemons such as ovn-controller.
  • The ovn-northd process talks to OVN Northbound- and Southbound-databases.
  • The ovsdb-server exposes endpoints over relations implemented by the ovsdb interface.
  • The charm supports clustering of the OVSDB, you must have a odd number of units for this to work. Note that write performance decreases as you increase the number of units.
  • Running multiple ovn-northd daemons is supported and they will operate in active/passive mode. The daemon uses a locking feature in the OVSDB to automatically choose a single active instance.
  • The charm MUST configure TLS transport between OVSDB and its clients supporting both charm static configuration or with help from vault and the tls-certificates interface.
• ovn-chassis
  • Subordinate charm that deploys the OVN local controller and Open vSwitch Database and Switch.
  • It connects up to the OVN Southbound database over the OVSDB protocol, down to the unit local Open vSwitch database over the OVSDB protocol and to the unit local Open vSwitch daemon via OpenFlow.
  • Each hypervisor, software gateway or other units in need of OVN networking runs its own independent copy of the ovn-controller daemon.
  • Modules to integrate with specific software, such as OpenStack nova-compute and Kubernetes worker, should all be added to this subordinate charm. Which module(s) to activate should be determined at runtime through presence of optional relations.
  • A LXD profile will be required for this charm to enable container placement of OVN/OVS components.
• ovn-dedicated-chassis
  • Principal charm for deployments that require a dedicated software gateway.
  • This charm will be built from the ovn-chassis subordinate codebase.
• neutron-api-plugin-ovn
  • Subordinate charm that deploys the networking-ovn component on neutron-api units and augments Neutron's configuration for use with the OVN ML2 plugin.
• octavia-ovn-provider
  • Subordinate charm that deploys the networking-ovn component on octavia units and augments Octavia's configuration for use with the OVN provider driver.

The implementation consists of the following interfaces:

• ovsdb
  • Interface that facilitates a provider charm to publish connection properties of a OVSDB.
  • Interface that facilitates a requirer charm to consume a remote OVSDB.
• octavia-provider
  • Interface that facilitates a provider subordinate charm to publish information about a Octavia provider driver to and to trigger restart of the Octavia service.
  • Interface that facilitates the Octavia charm to add provider information and react to restart requests from a subordinate provider charm.

The charms should be implemented in such a way so that the non-OpenStack specific components can be deployed with other software components such as the Charmed Distribution of Kubernetes.

Wherever possible and relevant, existing interfaces or charm libraries should be consumed or extended to work with the new charms.

Assignee(s)

Primary assignee:

fnordahl

Gerrit Topic

Use Gerrit topic "ovn-charm" for all patches related to this spec.

git-review -t ovn-charm

Work Items

See Implementation section

Repositories

• charm-ovn
• charm-ovn-controller
• charm-ovn-dedicated-controller
• charm-neutron-api-plugin-ovn
• charm-octavia-ovn-provider
• charm-interface-ovsdb
• charm-interface-octavia-provider

Documentation

Each charm should contain a README with instructions on deploying the charm.

In addition to that a appendix will be added to the deployment guide with details about how to deploy OpenStack with OVN.

Security

Communication between OVSDB and its clients is authenticated and secured by the use of TLS and PKI. This must be implemented using secure best practices.

TLS configuration should be possible both statically through configuration and through automatic certificate provisioning with vault and the tls-certificates interface.

Testing

Code written or changed will be covered by unit tests; functional testing will be implemented using the Zaza framework.

Dependencies

• There may be need for changes to the layout of the openvswitch source package to cater for running the ovsdb-server process without having the package attempting to configure the switching components. This will help with container placement of the ovsdb charm without requiring a LXD profile.
• There may be need for changes to the layout of the netwokring-ovn source package to cater for Octavia provider driver enablement.