[Windows] Prepare-AntreaAgent.ps1 fails for containerized ovs

[antoninbas]

Describe the bug
I am trying to add a Windows Node to a K8s cluster using the "containerized OVS" installation method for Antrea.
When trying to run Prepare-AntreaAgent.ps1, I get the following error:

PS C:\k\antrea> .\Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false
Cleaning stale Antrea network resources if they exist...
[SC] CreateService SUCCESS
[SC] ChangeServiceConfig2 SUCCESS
Start-Service : Service 'ovsdb-server (ovsdb-server)' cannot be started due to the following error: Cannot start service ovsdb-server on computer '.'.
At C:\k\antrea\Clean-AntreaNetwork.ps1:80 char:5
+     Start-Service ovsdb-server
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : OpenError: (System.ServiceProcess.ServiceController:ServiceController) [Start-Service], ServiceCommandException
    + FullyQualifiedErrorId : CouldNotStartService,Microsoft.PowerShell.Commands.StartServiceCommand

The error is generated by Clean-AntreaNetwork.ps1, which is invoked by Prepare-AntreaAgent.ps1.

We can see that the script tries to create an OVS service, which doesn't make sense for the containerized OVS case.

The following questions come to mind:

1. When running Prepare-AntreaAgent.ps1 with -RunOVSServices $false, should Clean-AntreaNetwork.ps1 be invoked with -OVSRunMode "container"?
2. When running Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false, it seems that Prepare-AntreaAgent.ps1 doesn't actually do anything besides calling Clean-AntreaNetwork.ps1. Is that accurate? I just want to check that my understanding is correct.

Versions:
Antrea v1.14 and top-of-tree

[antoninbas]

@Atish-iaf @NamanAg30 @rajnkamr

[Atish-iaf]

Hi @antoninbas

When running Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false, it seems that Prepare-AntreaAgent.ps1 doesn't actually do anything besides calling Clean-AntreaNetwork.ps1. Is that accurate? I just want to check that my understanding is correct.

Yes, and i think in case of containerized ovs instead of
.\Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false
we can use

# If OVS userspace processes were running inside container in antrea-agent Pod
./Clean-AntreaNetwork.ps1 -OVSRunMode "container"

https://github.com/antrea-io/antrea/blob/main/docs/windows.md#:~:text=%23%20If%20OVS%20userspace%20processes%20were%20running%20inside%20container%20in%20antrea%2Dagent%20Pod%0A./Clean%2DAntreaNetwork.ps1%20%2DOVSRunMode%20%22container%22
always, because incase of containerized OVS, -RunOVSServices will always be false and -InstallKubeProxy will also be false as -InstallKubeProxy is true for k8s version prior to 1.26 but ovs containerization uses windows host process as true which was GA in k8s 1.26.

[antoninbas]

In any case, it would make sense to fix .\Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false. Even if Clean-AntreaNetwork.ps1 can be run directly, we would just make the documentation more complicated by calling this out.

[antoninbas]

If it's just about invoking Clean-AntreaNetwork.ps1 with the correct OVSRunMode flag, I can take care of it. I'll just need folks to review the PR and tell me if I'm missing something.

[rajnkamr]

2. When running Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false, it seems that Prepare-AntreaAgent.ps1 doesn't actually do anything besides calling Clean-AntreaNetwork.ps1. Is that accurate? I just want to check that my understanding is correct.

@antoninbas
In Ovs containerization case,
"Prepare-AntreaAgent.ps1 -InstallKubeProxy $false -RunOVSServices $false" will only be used for calling Clean-AntreaNetwork.ps1 to clean antrea-hns network / Remove stale network resources created by antrea-agent after the Windows Node reboots and will not start ovs services.

I also think it is better to still use Prepare-AntreaAgent.ps1 and invoke Clean-AntreaNetwork.ps1 with right parameters in ovs containerization case.