tc eBpf demo of Nodeport N-S load balancing and SNAT/ DNAT using recently added kfuncs to support connection tracking and NAT using eBpf programs. This could also be an option to implement L4 Route services for the Kubernetes Gateway API using these new eBpf functions.

Notes:

• The design is based on Approach A2 as documented here.
• The current version is an initial Proof of Concept/ demo currently meant to validate Approach A2 and the use of the newly added kfuncs for managing kernel connection tracking (conntrack) tables.
• This requires a system built with a custom kernel currently (it has been tested using a kernel from bpf-next/ 6.0.0-rc3)
• To build, first recursively load all the sub-modules at the top of the repo (git submodule update --init --recursive), then 'make tc' under src

A Tech Talk and demo of this project is available here.

For the initial demo, the eBpf program is invoked from a CLI command and not via a Kubernetes controller for services (this is to be addressed in a following rev). To run the demo, create a Kubernetes deployment and provide the NodePort and backends via the CLI invocation on the Kubernetes worker nodes. For example: tc eth0 <nodeport> <backend_ip_1> <backend_ip_2> <targetPort>. (For example tc eth0 31000 10.240.1.2 10.240.1.3 80).

Additional details to be added with future updates ...