Ability to specify `ofport_request` in the network configuration

[courtland]

What this PR does / why we need it:

Enables plugin configuration to request a specific ofport number when attaching a container to the host's OVS bridge.

This PR adds a new ofport_request integer field to the network configuration options.

Also addresses the old issue #73.

If the ofport_request field is omitted, the plugin continues to let OVS choose an available port. If the requested ofport is already in use, OVS will automatically choose another free ofport. See man ovs-vswitchd.conf.db(5) for more information about ofport_request behavior.

Special notes for your reviewer:

I am using this as a CNI plugin in conjunction with HashiCorp Nomad and an OpenFlow SDN controller, although I imagine there are use cases for k8s as well. The fixed ofport is required to play nicely with the SDN controller. Containers are bridged into an OVS bridge datapath handled by the OpenFlow controller.

Although I tried to mirror the behavior with the existing OvnPortName option, I am not able to pass along/modify CNI_ARGS through Nomad, which is somewhat related to https://github.com/hashicorp/nomad/issues/13520. This is why I opted to include it in the network configuration along with the vlan/mtu/bridge/etc.

Release note:

Added the ability to request a static OVS `ofport` number via a new `ofport_request` field in the Network Configuration

[kubevirt-bot]

Hi @courtland. Thanks for your PR.

I'm waiting for a k8snetworkplumbingwg member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[phoracek]

Thanks for opening this @courtland, I will review this during the next week.

[courtland]

Thanks for taking a look at this. I have improved the test, so hopefully it is good to merge. I am fine with waiting for #227 - building from my fork solves my immediate problem for the time being.

[phoracek]

/retest

Looks good, thanks!

[phoracek]

@courtland would you please fix this lint error?

/tmp/src/github.com/k8snetworkplumbingwg/ovs-cni/.gopath/src/github.com/k8snetworkplumbingwg/ovs-cni/pkg/plugin/plugin_test.go:670:5: don't use underscores in Go names; var ofport_request should be ofportRequest

[courtland]

@phoracek lint error is fixed - Sorry, too much Python lately and not enough Go 🤦

[phoracek]

Haha, no worries!

[phoracek]

@courtland would you please rebase the PR, so we could merge it?

[courtland]

@phoracek squashed and rebased against latest main

[phoracek]

/retest

[courtland]

@phoracek I'm having trouble understanding whether or not the test failures are something bad with my rebase, or if they are related to errors in the recent port mirroring changes, as they seem specific to creating mirror ports. Any hints?

[phoracek]

It seems like a transient error, not related to this PR.

/retest

[phoracek]

/override pull-e2e-ovs-cni

It failed on an unrelated port mirroring test

[phoracek]

/retest

Sorry about the trouble, I'm working on stabilization of the test in another PR.

[phoracek]

/retest

[phoracek]

/lgtm /approve

[kubevirt-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: courtland, phoracek

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/k8snetworkplumbingwg/ovs-cni/blob/main/OWNERS)~~ [phoracek] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[phoracek]

Thanks @courtland !

[courtland]

No worries, thanks for merging it!