bridge: Enable disabling bridge interface

[ormergi]

The new disableContainerInterface parameter is added to the bridge plugin to enable setting the container interface state down.

When the parameter is enabled, the container interface (veth peer that is placed at the container ns) remain down (i.e: disabled). The bridge and host peer interfaces state are not affected by the parameter.

Notes for reviewers:

• Since IPAM logic involve various configurations including waiting for addresses to be realized and setting the interface state UP, the new parameter cannot work with IPAM. In case both IPAM and DisableContainerInterface parameters are set, the bridge plugin will raise an error.
• CNI versions 0.1.0 and 0.2.0 result expect single IP addresses, where newer versions expect multiple addresses (slice). When the new parameter is set, there will be no IP to report, thus it cannot work with older versions. In newer versions it works and an empty IP addresses slice will return.

Related Issue: https://github.com/containernetworking/plugins/issues/951

[ormergi]

/cc @EdDev @AlonaKaplan

[ormergi]

Changes: fix linter issues

[ormergi]

Changes: add failing test when both IPAM and disable-interface parameters are set

[ormergi]

have you checked if there is something to do for the check command? Does it verify that the link is up?

Hi @mlguerrero12 thanks for the review :grinning: , from what I saw the check cmd does not check the interface state at all.

[squeed]

From what I saw the check cmd does not check the interface state at

Hah. Oops :-). Well, that would be good to fix, but it could be in a separate PR :grimacing:

[ormergi]

Hey @squeed please take another look, let me know if there is anything else we should do :slightly_smiling_face:

[ormergi]

Updating docs PR https://github.com/containernetworking/cni.dev/pull/137

[squeed]

Thanks for your contribution!