Hello, I have updated an external engine from 4.3 to 4.4 and the OVN configuration seems to have been retained: [root@ovmgr1 ovirt-engine]# ovn-nbctl show switch fc2fc4e8-ff71-4ec3-ba03-536a870cd483 (ovirt-ovn192-1e252228-ade7-47c8-acda-5209be358fcf) switch 101d686d-7930-4176-b41a-b306d7c30a1a (ovirt-ovn17217-4bb1d1a7-020d-4843-9ac7-dc4204b528e5) port c1ec60a4-b4f3-4cb5-8985-43c086156e83 addresses: ["00:1a:4a:19:01:89 dynamic"] port 174b69f8-00ed-4e25-96fc-7db11ea8a8b9 addresses: ["00:1a:4a:19:01:59 dynamic"] port ccbd6188-78eb-437b-9df9-9929e272974b addresses: ["00:1a:4a:19:01:88 dynamic"] port 7e96ca70-c9e3-4efe-9ac5-e56c18476437 addresses: ["00:1a:4a:19:01:83 dynamic"] port d2c2d9f1-8fc3-4f17-9ada-76fe3a168e65 addresses: ["00:1a:4a:19:01:5e dynamic"] port 4d13d63e-5ff3-41c1-9b6b-feac343b514b addresses: ["00:1a:4a:19:01:60 dynamic"] port 66359e79-56c4-47e0-8196-2241706329f6 addresses: ["00:1a:4a:19:01:68 dynamic"] switch 87012fa6-ffaa-4fb0-bd91-b3eb7c0a2fc1 (ovirt-ovn193-d43a7928-0dc8-49d3-8755-5d766dff821a) port 2ae7391b-4297-4247-a315-99312f6392e6 addresses: ["00:1a:4a:19:01:51 dynamic"] switch 9e77163a-c4e4-4abf-a554-0388e6b5e4ce (ovirt-ovn172-4ac7ba24-aad5-432d-b1d2-672eaeea7d63) [root@ovmgr1 ovirt-engine]# Then I updated one of the 3 Linux hosts (not node ng) through remove from web admin gui, install from scratch of CentOS 8.2 OS, configure repos and then add new host (with the same name) in engine and I was able to connect to storage (iSCSI) and start VMs in general on the host. Coming to OVN part it seems it has not been configured on the upgraded host. Is it expected? Eg on engine I only see chassis for the 2 hosts still in 4.3: [root@ovmgr1 ovirt-engine]# ovn-sbctl show Chassis "b8872ab5-4606-4a79-b77d-9d956a18d349" hostname: "ov301.mydomain" Encap geneve ip: "10.4.192.34" options: {csum="true"} Port_Binding "174b69f8-00ed-4e25-96fc-7db11ea8a8b9" Port_Binding "66359e79-56c4-47e0-8196-2241706329f6" Chassis "ddecf0da-4708-4f93-958b-6af365a5eeca" hostname: "ov300.mydomain" Encap geneve ip: "10.4.192.33" options: {csum="true"} Port_Binding "ccbd6188-78eb-437b-9df9-9929e272974b" [root@ovmgr1 ovirt-engine]# What to do to add the upgraded 4.4 host? Can they live together for the OVN part? Thanks, Gianluca