Implementing multicast connectivity test

[yushoyamaguchi]

Proposal / RFE

We would like to implement a connectivity test for multicast.

#2574

[yushoyamaguchi]

Some questions:

• To what extent Multicast E2E test is required ?
  • You definitely want it, or you'll review it if you can afford it ?

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• How should we prepare a container image by which we can use both IGMP and multicast communication check tool(s) ?
  • Idea1 : FRR or so on for IGMP and iperf2/socat or so on for multicast communication check
    • A test scenario which check the contents of stdout is allowed? (we cannot check using exit-code when using iperf2)
  • Idea2 : Using ROS2 and related middleware for both enabling IGMP and checking communication.
    • It will become simple but is it allowed to rely on ROS2?

---

• Is it allowed to create a test scenario which affects the state of cilium-agent?
  • In multicast, remote-node must be registered in each node to achieve communication. (by cilium-dbg or cilium-cli subcommand)
  • One idea : Make it a prerequisite for the test that some multicast settings are already included

[harsimran-pabla]

To what extent Multicast E2E test is required ?
You definitely want it, or you'll review it if you can afford it ?

We would definitely want it since more functionality is being added to cilium bpf code and cilium-cli,
it is natural that we want some sort of automated testing to ensure that there is no regression
introduced.

There are couple of incentives to get these tests completed sooner rather than later:

• Before we introduce any new functionality to existing multicast implementation (cli or bpf), we should
  get e2e tests first.
• In order to move this feature out of beta, we need to have e2e tests.

I will be happy to review the changes as well as provide feedback on proposed test scenarios.

[harsimran-pabla]

How should we prepare a container image by which we can use both IGMP and multicast communication check tool(s) ?

Consider using https://github.com/nicolaka/netshoot container. You can use the socat utility to send and receive multicast packets; it will also send IGMP to join/leave messages.

http://www.dest-unreach.org/socat/doc/socat-multicast.html

[harsimran-pabla]

Is it allowed to create a test scenario which affects the state of cilium-agent?

I am not sure if I understand this correctly, cilium agent state is modified by CLIs; is there any other state change you have in mind?

I'd say define the test cases, and we can go over the details of such scenarios.

[yushoyamaguchi]

@harsimran-pabla
Thank you for your comment.
I'll start implementation using socat.

Regarding the third concern, in APAC Dev MTG, I was told that as long as I return to the original state finally, I can put the settings in cilium-agent for testing purposes. (In this case, I would register a multicast group and its remote subscribers to cilium-agent(BPF map of multicast) for E2E test temporarily. )

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Closing.