home-network-k3s-impl/apps/gitea-actions.yaml

---
# Gitea Actions runner (act_runner) — Phase 6 CI/CD (WS-GITOSS).
#
# WHY A DEDICATED, NON-APP NAMESPACE:
#   The runner's job executor is a Docker-in-Docker (DinD) sidecar that MUST run
#   `privileged: true` (dockerd needs it). The Kyverno `restrict-host-namespaces`
#   policy denies privileged containers, but it (and the egress-class / auth-mode /
#   default-deny-baseline policies) scope ONLY to namespaces labeled
#   homelab.keithjackson.dev/app-namespace: "true". This namespace deliberately does
#   NOT carry that label — it is CI plumbing, not a user-facing app — so the privileged
#   DinD sidecar is admitted WITHOUT a policy exception. (Verified: a privileged Pod in
#   a non-app namespace passes server-side admission; Kyverno test fixture
#   `platform-workload` is likewise Excluded from restrict-host-namespaces.)
#
# EXECUTOR MODEL — Docker executor + DinD sidecar (privileged):
#   act_runner runs each job step inside a container it launches via a Docker daemon.
#   That daemon is the co-located `dind` sidecar (shared pod netns → tcp://localhost:2376,
#   TLS via a shared emptyDir of certs). Tradeoff vs the host/self-hosted executor: DinD
#   needs `privileged`, but it gives clean per-job isolation and lets the workflow pick its
#   own job image (the pinned toolchain), which the host executor cannot. Privileged is
#   contained to this CI-only namespace and the runner mounts NO ServiceAccount token
#   (automountServiceAccountToken: false) — CI holds no cluster credentials (R-SEC-02).
apiVersion: v1
kind: Namespace
metadata:
  name: gitea-actions
  labels:
    # NOTE: intentionally NO homelab.keithjackson.dev/app-namespace label (see header).
    homelab.keithjackson.dev/ci: act-runner
---
# Default-deny ingress; broad egress (a CI runner legitimately needs the internet:
# ghcr.io / github.com / docker hub / dl.k8s.io / pypi for job images + pinned tools,
# and the Gitea ingress VIP for registration + repo clone). Nothing connects INTO the
# runner, so ingress is denied entirely.
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default-deny-ingress-allow-egress
  namespace: gitea-actions
  labels:
    homelab.keithjackson.dev/baseline: default-deny
spec:
  podSelector: {}
  policyTypes:
    - Ingress
    - Egress
  ingress: []
  egress:
    # DNS (cluster + split-horizon resolution of gitea.home.keithjackson.dev).
    - to:
        - namespaceSelector:
            matchLabels:
              kubernetes.io/metadata.name: kube-system
      ports:
        - protocol: UDP
          port: 53
        - protocol: TCP
          port: 53
    # Everything else the runner + DinD need: Gitea VIP + internet registries/tool hosts.
    - {}
---
# Runner state (config.yaml + the `.runner` registration file) persists here so the
# runner registers exactly ONCE and reuses its identity across restarts (no duplicate
# offline rows in Gitea). RWO → Deployment strategy must be Recreate (fix/recreate-strategy-rwo).
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: act-runner-data
  namespace: gitea-actions
  labels:
    app.kubernetes.io/name: act-runner
spec:
  accessModes:
    - ReadWriteOnce
  storageClassName: longhorn
  resources:
    requests:
      storage: 1Gi
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: act-runner
  namespace: gitea-actions
  labels:
    app.kubernetes.io/name: act-runner
spec:
  replicas: 1
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app.kubernetes.io/name: act-runner
  template:
    metadata:
      labels:
        app.kubernetes.io/name: act-runner
    spec:
      # CI holds no cluster credentials — do not mount a SA token into the runner or
      # (via the shared netns) the job containers (R-SEC-02, docs/14).
      automountServiceAccountToken: false
      containers:
        # ---- act_runner: registers with Gitea, dispatches jobs to the DinD daemon ----
        - name: runner
          image: gitea/act_runner:0.2.11
          env:
            - name: GITEA_INSTANCE_URL
              value: https://gitea.home.keithjackson.dev
            - name: GITEA_RUNNER_REGISTRATION_TOKEN
              valueFrom:
                secretKeyRef:
                  name: gitea-actions-runner
                  key: token
            - name: GITEA_RUNNER_NAME
              value: incluster-dind
            # runs-on label -> job image. Both map to the catthehacker "act" image, which
            # carries bash/git/curl/tar/python3+pip/node so .gitea/workflows scripts can
            # install the pinned CI toolchain (ci/versions.env) and actions/checkout runs.
            - name: GITEA_RUNNER_LABELS
              value: "ubuntu-latest:docker://ghcr.io/catthehacker/ubuntu:act-22.04,homelab:docker://ghcr.io/catthehacker/ubuntu:act-22.04"
            # Reach the DinD daemon over the shared pod network namespace, TLS-verified
            # against the certs the sidecar drops into the shared /certs emptyDir.
            - name: DOCKER_HOST
              value: tcp://localhost:2376
            - name: DOCKER_CERT_PATH
              value: /certs/client
            - name: DOCKER_TLS_VERIFY
              value: "1"
          volumeMounts:
            - name: data
              mountPath: /data
            - name: certs
              mountPath: /certs
              readOnly: true
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              memory: 512Mi
        # ---- Docker-in-Docker: the job executor daemon (privileged) ----
        - name: dind
          image: docker:27-dind
          securityContext:
            privileged: true
          env:
            # Generate + publish TLS certs into the shared emptyDir; dockerd then listens
            # on tcp://0.0.0.0:2376 (TLS) which the runner reaches at localhost:2376.
            - name: DOCKER_TLS_CERTDIR
              value: /certs
          volumeMounts:
            - name: certs
              mountPath: /certs
            - name: dind-storage
              mountPath: /var/lib/docker
          resources:
            requests:
              cpu: 100m
              memory: 256Mi
            limits:
              memory: 2Gi
      volumes:
        - name: data
          persistentVolumeClaim:
            claimName: act-runner-data
        - name: certs
          emptyDir: {}
        - name: dind-storage
          emptyDir: {}