feat(kubernetes): add cni-sidecar supervisor topology

Signed-off-by: Taylor Mutch <taylormutch@gmail.com>

Author: TaylorMutch

.agents/skills/debug-openshell-cluster/SKILL.md

@@ -285,6 +285,18 @@ workload entrypoint PID to `OPENSHELL_ENTRYPOINT_PID_FILE`
 should read it for binary-scoped policy decisions; if allowed network rules are
 all denied, inspect that file and the network sidecar logs.
 
+If `supervisor_topology = "cni-sidecar"` is rendered, the gateway should render
+the same process container and long-running network sidecar as sidecar mode, but
+there should be no `openshell-network-init` init container in sandbox pods.
+Instead, the chart must install the privileged `openshell-cni` DaemonSet and the
+sandbox pod should carry `openshell.ai/cni=enabled`,
+`openshell.ai/network-enforcement-mode=cni-sidecar`, and
+`openshell.ai/proxy-uid=<uid>` annotations. The CNI DaemonSet copies
+`/openshell-cni` into the host CNI binary directory and patches an existing CNI
+`.conflist`; if sandbox pods bypass network enforcement or fail during pod
+network setup, inspect the DaemonSet logs, the host CNI config, and whether the
+cluster actually invokes chained CNI plugins for the sandbox runtime class.
+
 If `supervisor_topology = "proxy-pod"` is rendered, each sandbox should have a
 separate supervisor Deployment with one supervisor pod, a headless supervisor
 Service, a proxy CA Secret, and two per-sandbox NetworkPolicies. The agent pod
@@ -305,6 +317,9 @@ Inspect all three when sandbox registration or egress enforcement fails:
 kubectl -n openshell get configmap openshell-config -o jsonpath='{.data.gateway\.toml}' | grep supervisor_topology
 kubectl -n <sandbox-namespace> get pod <sandbox-pod> -o jsonpath='{range .spec.initContainers[*]}{.name}{" "}{.command}{"\n"}{end}'
 kubectl -n <sandbox-namespace> get pod <sandbox-pod> -o jsonpath='{range .spec.containers[*]}{.name}{" "}{.command}{"\n"}{end}'
+kubectl -n <sandbox-namespace> get pod <sandbox-pod> -o jsonpath='{.metadata.annotations}'
+kubectl -n openshell get daemonset,pod -l app.kubernetes.io/component=cni
+kubectl -n openshell logs daemonset/openshell-cni -c install-cni --tail=200
 kubectl -n <sandbox-namespace> logs <sandbox-pod> -c openshell-network-init --tail=200
 kubectl -n <sandbox-namespace> logs <sandbox-pod> -c openshell-supervisor-network --tail=200
 kubectl -n <sandbox-namespace> logs <sandbox-pod> -c agent --tail=200
@@ -338,6 +353,7 @@ openshell logs <sandbox-name>
 | Kubernetes gateway pod crash loops | Missing secret, bad DB URL, bad TLS config | `kubectl -n openshell logs deployment/openshell -c openshell-gateway` or `kubectl -n openshell logs statefulset/openshell -c openshell-gateway` |
 | CLI TLS error | Local mTLS bundle does not match server cert/CA | Check `~/.config/openshell/gateways/<name>/mtls/` |
 | Image pull failure | Gateway or sandbox image cannot be pulled | Runtime events and image pull credentials |
+| CNI-sidecar sandbox pods fail network setup | OpenShell CNI DaemonSet did not patch the node CNI conflist, cannot read pods, or the runtime class does not invoke the chained plugin | `kubectl -n openshell logs daemonset/openshell-cni -c install-cni`, chart `cni.*` values, host CNI config |
 | `K8s namespace not ready` with `envoy-gateway-openshell.yaml: the server could not find the requested resource` | Optional Gateway API manifest was applied without Envoy Gateway CRDs, or k3s Helm controller startup exceeded the namespace wait | Apply `deploy/kube/manifests/envoy-gateway-openshell.yaml` manually only after Envoy Gateway is installed and `grpcRoute` is enabled |
 
 ## Reporting

.agents/skills/helm-dev-environment/SKILL.md

@@ -65,6 +65,11 @@ mise run helm:skaffold:run
 mise run helm:skaffold:run:sidecar
 ```
 
+**Supervisor CNI-sidecar topology** (build once and leave running):
+```bash
+mise run helm:skaffold:run:cni-sidecar
+```
+
 **Supervisor proxy-pod topology** (build once and leave running):
 ```bash
 mise run helm:skaffold:run:proxy-pod
@@ -73,7 +78,9 @@ mise run helm:skaffold:run:proxy-pod
 All Skaffold commands build the `gateway` and `supervisor` images and deploy the OpenShell Helm
 chart. The sidecar profile renders an `openshell-network-init` init container for
 nftables setup and a non-root `openshell-supervisor-network` runtime sidecar for
-proxying. The proxy-pod profile renders network supervision in a separate
+proxying. The cni-sidecar profile enables the privileged OpenShell CNI
+DaemonSet and uses the sidecar runtime model without the pod-local network init
+container. The proxy-pod profile renders network supervision in a separate
 supervisor Deployment with one pod and relies on Kubernetes NetworkPolicy
 enforcement so the agent pod can reach only its paired supervisor plus DNS. The
 default local k3s/k3d cluster keeps k3s's embedded NetworkPolicy controller
@@ -104,6 +111,12 @@ Run the sidecar topology e2e environment:
 mise run e2e:kubernetes:sidecar
 ```
 
+Run the CNI-sidecar topology e2e environment:
+
+```bash
+mise run e2e:kubernetes:cni-sidecar
+```
+
 Run the proxy-pod topology e2e environment:
 
 ```bash
@@ -176,6 +189,12 @@ For a sidecar-profile deployment:
 mise run helm:skaffold:delete:sidecar
 ```
 
+For a cni-sidecar-profile deployment:
+
+```bash
+mise run helm:skaffold:delete:cni-sidecar
+```
+
 For a proxy-pod-profile deployment:
 
 ```bash
@@ -307,6 +326,7 @@ for dependencies still declared in `Chart.yaml`.
 | `deploy/helm/openshell/ci/values-high-availability.yaml` | HA test overlay (`replicaCount: 2` with external PostgreSQL Secret) |
 | `deploy/helm/openshell/ci/values-keycloak.yaml` | Keycloak OIDC overlay |
 | `deploy/helm/openshell/ci/values-sidecar.yaml` | Supervisor sidecar topology overlay for Kubernetes e2e/dev |
+| `deploy/helm/openshell/ci/values-cni-sidecar.yaml` | Supervisor CNI-sidecar topology overlay for Kubernetes e2e/dev; enables the OpenShell CNI DaemonSet |
 | `deploy/helm/openshell/ci/values-proxy-pod.yaml` | Supervisor proxy-pod topology overlay for Kubernetes e2e/dev; requires NetworkPolicy enforcement |
 | `deploy/helm/openshell/ci/values-spire.yaml` | SPIFFE/SPIRE provider token grant overlay |
 | `deploy/helm/openshell/ci/values-spire-stack.yaml` | SPIRE hardened chart values for local dev |

.github/workflows/docker-build.yml

@@ -246,6 +246,9 @@ jobs:
           fi
           mkdir -p "$stage"
           install -m 0755 "$found" "$stage/$binary"
+          if [[ "${{ inputs.component }}" == "supervisor" ]]; then
+            PREBUILT_ARCH="${{ matrix.arch }}" tasks/scripts/stage-prebuilt-binaries.sh cni
+          fi
           ls -lh "$stage/"
 
       - name: Build ${{ inputs.component }} image

Cargo.lock

@@ -89,19 +89,23 @@ Driver-controlled environment variables must override sandbox image or template
 values for sandbox ID, sandbox name, gateway endpoint, relay socket path, TLS
 paths, and command metadata.
 
-Kubernetes can run the supervisor in the default combined topology or in a
-sidecar topology. Combined mode keeps network and process supervision in the
+Kubernetes can run the supervisor in combined, sidecar, cni-sidecar, or
+proxy-pod topology. Combined mode keeps network and process supervision in the
 agent container. Sidecar mode runs network enforcement, the proxy, and gateway
 loopback forwarding in a dedicated sidecar, while the agent container runs only
 the process-supervision leaf and launches the user workload after the sidecar
 signals readiness. In sidecar mode, an init container performs the privileged
 pod-network nftables setup with `NET_ADMIN` and hands shared state ownership to
 the configured proxy UID; the long-running network sidecar runs as that UID and
-does not keep `NET_ADMIN`. The agent container runs as the resolved sandbox
-UID/GID with no added Linux capabilities. Sidecar mode preserves gateway session
-and SSH behavior, but treats the process leaf as network-only: Landlock
-filesystem policy, process privilege dropping, and process/binary identity
-checks are not applied there.
+does not keep `NET_ADMIN`. CNI-sidecar mode keeps the sidecar runtime model but
+requires the privileged OpenShell CNI DaemonSet to install the pod-network rules
+during CNI `ADD` using nftables or iptables. Proxy-pod mode moves network
+enforcement into a paired supervisor Deployment and requires NetworkPolicy
+enforcement. The agent container runs as the resolved sandbox UID/GID with no
+added Linux capabilities in the alternate topologies. They preserve gateway
+session and SSH behavior, but
+treat the process leaf as network-only: Landlock filesystem policy, process
+privilege dropping, and process/binary identity checks are not applied there.
 
 ## Images
 

architecture/compute-runtimes.md

@@ -0,0 +1,29 @@
+# SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# SPDX-License-Identifier: Apache-2.0
+
+[package]
+name = "openshell-cni"
+description = "OpenShell chained CNI plugin for Kubernetes sidecar network enforcement"
+version.workspace = true
+edition.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+base64 = { workspace = true }
+miette = { workspace = true }
+reqwest = { workspace = true, features = ["blocking"] }
+serde = { workspace = true }
+serde_json = { workspace = true }
+serde_yml = { workspace = true }
+tempfile = "3"
+
+[target.'cfg(target_os = "linux")'.dependencies]
+libc = "0.2"
+
+[dev-dependencies]
+tempfile = "3"
+
+[lints]
+workspace = true