# Istio CNI Node Agent

The Istio CNI Node Agent is responsible for several things

- Install an Istio CNI plugin binary on each node's filesystem, updating that node's CNI config in e.g (`/etc/cni/net.d`), and watching the config and binary paths to reinstall if things are modified.

	// This is effectively an analog for Istio's old-style podSpec-based health check rewrites.
	// Before Istio would update the pod manifest to rewrite healthchecks to go to sidecar Envoy port 15021,
	// so that it could distinguish things that can be unauthenticated (healthchecks) from other kinds of node traffic
	// (e.g. LoadBalanced Service packets, etc) that need to be authenticated/captured/proxied.
	//

// and iptables will be smart enough to pick the correct underlying set (v4 or v6, based on context),
// reducing the # of rules we need.
//
// BUT netlink lib doesn't support adding things to `list:set` types yet, and current tagged release
// doesn't support creating `list:set` types yet (is in main branch tho).
// So this will actually create 2 underlying ipsets, one for v4 and one for v6

            - ALL
            add: # See https://man7.org/linux/man-pages/man7/capabilities.7.html
            - NET_ADMIN # Required for TPROXY and setsockopt
            - SYS_ADMIN # Required for `setns` - doing things in other netns
            - NET_RAW # Required for RAW/PACKET sockets, TPROXY
          readOnlyRootFilesystem: true
          runAsGroup: 1337
          runAsNonRoot: false
          runAsUser: 0