KubeCon + CloudNativeCon India 2026

The Linux Netlink API is the kernel’s structured communication channel for the user space, enabling interaction with subsystems such as routing, netfilter, and interface management. Introduced as a modern replacement for ioctl, Netlink provides a message-based architecture where the user space and the kernel exchange serialized binary messages through dedicated Netlink families. This session explores how Netlink’s extensible design and attribute-based encoding enable efficient communication between layers of the networking stack.

We’ll then demonstrate how these capabilities can be leveraged in cloud-native systems - showcasing how we are using netlink in kube-proxy to interact with the netfilter accounting (nfacct) subsystem for in-kernel packet counting, and how we recently shifted conntrack cleanup from a user-space binary-based approach to Netlink, significantly reducing connection cleanup time from minutes to seconds.