- In ambient mode, the CNI plugin does not configure any networking, but is only responsible for synchronously pushing new pod events back up to an ambient watch server which runs as part of the Istio CNI node agent. The ambient server will find the pod netns and configure networking inside that pod via iptables. The ambient server will additionally watch enabled namespaces, and enroll already-started-but-newly-enrolled pods in a similar fashion.

## Privileges required

```mermaid
graph LR
    subgraph Client Node
        Client
        CZ["Ztunnel"]
    end
    subgraph Server Node
        Server
        SZ["Ztunnel"]
    end
    Client--Plain-->CZ
    CZ-."HBONE (target)".->Server
    CZ--"HBONE (actual)"-->SZ
    SZ--Plain-->Server
```

### Pooling

User connections can be multiplexed over shared HBONE connections.

default            sleep-7656cf8794-lxcmx                               10.244.2.58 ambient-worker2       None                                HBONE
gateway-system     gateway-api-admission-server-85985d48ff-5jcvd        10.244.2.8  ambient-worker2       None                                TCP

AGENT_BINARIES:=./pilot/cmd/pilot-agent
STANDARD_BINARIES:=./istioctl/cmd/istioctl \
  ./pilot/cmd/pilot-discovery \
  ./pkg/test/echo/cmd/client \
  ./pkg/test/echo/cmd/server \
  ./samples/extauthz/cmd/extauthz \
  ./operator/cmd/operator

# These are binaries that require Linux to build, and should
# be skipped on other platforms. Notably this includes the current Linux-only Istio CNI plugin