feat: adding stateless CNI support for ACI

[behzad-mir]

feat: adding stateless CNI support for ACI>
New entry in CNS statefile will be added for a container upon updateEndpoint request if the entry does not already exist. This covers a special case for ACI.

In ACI the CNS path to allocate IP address and send goalstate is different than CNS IPAM for Cilium and azure-cni for AKS. As a result, the endpoint entry for statefile is not getting create upon IP allocation and this fix will create the whole entry when CNI send updateEndpoint API request to CNS.

• uses conventional commit messages
• includes documentation
• adds unit tests
• relevant PR labels added

Notes:

[jackieluc]

LGTM. we tested this in an integration environment with ACI and it solved the issue we faced

[QxBytes]

could you add the details of the special case in the pr description (like the timeline of events and why there is no entry in the cns state by the time we call update endpoint helper)-- I thought the endpoint state is usually populated in updateEndpointState in cns, unless we don't request ips? Is InfraContainerID (in update endpoint state) typically equal to endpointID (in update endpoint helper)?

[behzad-mir]

could you add the details of the special case in the pr description (like the timeline of events and why there is no entry in the cns state by the time we call update endpoint helper)-- I thought the endpoint state is usually populated in updateEndpointState in cns, unless we don't request ips? Is InfraContainerID (in update endpoint state) typically equal to endpointID (in update endpoint helper)?

DOne

[tamilmani1989]

can we write UT for this case

[behzad-mir]

can we write UT for this case

Done

[behzad-mir]

/azp run Azure Container Networking PR

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