OVN Upgrades

Since OVN is a distributed system, special consideration must be given to the process used to upgrade OVN across a deployment. This document discusses the recommended upgrade process.

Release Notes

You should always check the OVS and OVN release notes (NEWS file) for any release specific notes on upgrades.

OVS

OVN depends on and is included with OVS. It’s expected that OVS and OVN are upgraded together, partly for convenience. OVN is included in OVS releases so it’s easiest to upgrade them together. OVN may also make use of new features of OVS only available in that release.

Upgrade ovn-controller

You should start by upgrading ovn-controller on each host it’s running on. First, you upgrade the OVS and OVN packages. Then, restart the ovn-controller service. You can restart with ovn-ctl:

$ sudo /usr/share/openvswitch/scripts/ovn-ctl restart_controller

or with systemd:

$ sudo systemd restart ovn-controller

Upgrade OVN Databases and ovn-northd

The OVN databases and ovn-northd should be upgraded next. Since ovn-controller has already been upgraded, it will be ready to operate on any new functionality specified by the database or logical flows created by ovn-northd.

Upgrading the OVN packages installs everything needed for an upgrade. The only step required after upgrading the packages is to restart ovn-northd, which automatically restarts the databases and upgrades the database schema, as well.

You may perform this restart using the ovn-ctl script:

$ sudo /usr/share/openvswitch/scripts/ovn-ctl restart_northd

or if you’re using a Linux distribution with systemd:

$ sudo systemctl restart ovn-northd

Schema Change

During database upgrading, if there is schema change, the DB file will be converted to the new schema automatically, if the schema change is backward compatible. OVN tries the best to keep the DB schemas backward compatible.

However, there can be situations that an incompatible change is reasonble. An example of such case is to add constraints in the table to ensure correctness. If there were already data that violates the new constraints got added somehow, it will result in DB upgrade failures. In this case, user should manually correct data using ovn-nbctl (for north-bound DB) or ovn-sbctl (for south- bound DB), and then upgrade again following previous steps. Below is a list of known impactible schema changes and how to fix when error encountered.

1. Release 2.11: index [type, ip] added for Encap table of south-bound DB to prevent duplicated IPs being used for same tunnel type. If there are duplicated data added already (e.g. due to improper chassis management), a convenient way to fix is to find the chassis that is using the IP with command:

   $ ovn-sbctl show
   

   Then delete the chassis with command:

   $ ovn-sbctl chassis-del <chassis>
   

Upgrading OVN Integration

Lastly, you may also want to upgrade integration with OVN that you may be using. For example, this could be the OpenStack Neutron driver or ovn-kubernetes.

OVN’s northbound database schema is a backwards compatible interface, so you should be able to safely complete an OVN upgrade before upgrading any integration in use.