- kubeadm: removed preflight check for existence of the conntrack binary, as conntrack is no longer a kube-proxy dependency in version 1.32 and newer. ([#126953](https://github.com/kubernetes/kubernetes/pull/126953), [@aroradaman](https://github.com/aroradaman))

- `kube-proxy`: Added an option/flag for configuring the `nf_conntrack_tcp_be_liberal` sysctl (in the kernel's netfilter conntrack subsystem).  When enabled, `kube-proxy` will not install the `DROP` rule for invalid conntrack states, which currently breaks users of asymmetric routing. ([#120354](https://github.com/kubernetes/kubernetes/pull/120354), [@aroradaman](https://github.com/aroradaman))

### Feature

- `kubeproxy_conntrack_reconciler_deleted_entries_total` metric can be used to track cumulative sum of conntrack flows cleared by reconciler. ([#130204](https://github.com/kubernetes/kubernetes/pull/130204), [@aroradaman](https://github.com/aroradaman))

- Kubelet TCP and HTTP probes are now more effective using networking resources:
  conntrack entries, sockets. This is achieved by reducing the `TIME-WAIT` state
  of the connection to 1 second, instead of the defaults 60 seconds. This allows
  kubelet to free the socket, and free conntrack entry and ephemeral port associated. ([#115143](https://github.com/kubernetes/kubernetes/pull/115143), [@aojea](https://github.com/aojea))

- Optimized kube-proxy conntrack cleanup logic, reducing the time complexity of deleting stale UDP entries. This significantly improves performance when there are many stale connections to clean up. ([#135511](https://github.com/kubernetes/kubernetes/pull/135511), [@aojea](http...

- Fixes a regression introduced in 1.29 where conntrack entries for UDP connections
  to deleted pods did not get cleaned up correctly, which could (among other things)

- Updated CNI plugins to v1.7.1 ([#131602](https://github.com/kubernetes/kubernetes/pull/131602), [@adrianmoisey](https://github.com/adrianmoisey)) [SIG Cloud Provider, Node and Testing]
- Updated `conntrack` reconciler to consider a Service’s target port during cleanup of stale flow entries. ([#130542](https://github.com/kubernetes/kubernetes/pull/130542), [@aroradaman](https://github.com/aroradaman))

- Fixes a regression introduced in 1.29 where conntrack entries for UDP connections
  to deleted pods did not get cleaned up correctly, which could (among other things)

   * documentation.
   */
  public void add(Runnable runnable, Executor executor) {
    // Fail fast on a null. We throw NPE here because the contract of Executor states that it throws
    // NPE on null listener, so we propagate that contract up into the add method as well.
    checkNotNull(runnable, "Runnable was null.");
    checkNotNull(executor, "Executor was null.");

  * When annotating existing internal code, use `org.jetbrains.annotations.Contract`, e.g. `@Contract(null -> null; !null -> !null)`.
      When doing so, still annotate nullable parameters and the return type as `@Nullable`.
  * Do not use `@Contract` for public APIs.
  * For polynull public APIs, the solution has to be decided on a case-by-case basis.