{{- /* NetworkPolicy — the reference implementation for Gitea #5. Copy this file with the rest of template-chart and replace every xxx: the values paths (.Values.networkPolicy.*), the helper prefix and the podSelector label, exactly as in the other template files. EVERY COMMENT IN THIS FILE IS A TEMPLATE COMMENT, and that is not a style choice. A "#" comment is part of the RENDERED manifest: it travels into the cluster, shows up in `helm get manifest` and `kubectl get -o yaml`, and bloats every diff a reviewer reads. Reasoning belongs in a Go template comment, which renders nothing. This caught several rounds of this rollout. And a second-order trap found while writing this header: the prose inside a template comment must not spell out the comment's own closing delimiter. The parser ends the comment at the first occurrence, and the remaining prose is then emitted as manifest content - the render fails with "did not find expected node content", pointing at the template and not at the sentence. Describe the delimiters instead of quoting them. WHAT THIS OBJECT DOES, AND - MORE IMPORTANTLY - WHAT IT DOES NOT It is a CEILING ON REACHABILITY, not an authentication layer. Three limits are real and worth having: 1. ONLY THE DECLARED PORTS ARE REACHABLE AT ALL. Whatever else the process binds - a debug listener, a management interface the image opens by default, a port that appears in the next app version - is blocked without anyone having to notice it exists. This is the largest part of what a default-on policy buys in this repository. 2. EGRESS IS CAPPED BY PORT, so a compromised pod cannot open arbitrary outbound connections. 3. INGRESS IS CAPPED BY SOURCE for every port no network probe touches. And three things it does NOT do, each of which has to be written down per chart rather than quietly assumed: a. EGRESS IS COARSE. A NetworkPolicy matches CIDRs and selectors and NEVER hostnames, so "only to the database host" cannot be expressed. This cluster's CNI is Canal (Flannel plus Calico for policy), which has no FQDN rule; Calico's GlobalNetworkSet could express one but would bind every chart to Calico - the same argument that kept implementation- specific objects out of the Gateway-API sweep (Gitea #114). So each egress rule below permits its PORT to any destination. That is a limit of the object, not a shortcut. b. THE PROBED PORT IS OPEN INSIDE THE CLUSTER BY DEFAULT. See the long note on networkPolicy.probeSources in values.yaml. Narrowing it needs the worker node IPs, which this chart cannot know. c. A POLICY IS ONLY A BOUNDARY WHERE THE CNI ENFORCES ONE. An unenforced policy is accepted by the API server and filters nothing, so everything looks configured while nothing is filtered. Measured for this cluster (Canal, 6/6) and for the CI cluster (k3d, which brings k3s' own policy controller) - verify it rather than reading it off a value. ONE CLUSTER SETTING THIS WHOLE CONVENTION DEPENDS ON AND CANNOT CHECK: TRAEFIK MUST NOT RUN WITH hostNetwork. Measured on 2026-10-14: the rke2-traefik DaemonSet has no hostNetwork, and its pods carry real pod IPs (10.42.3.120, 10.42.4.94, 10.42.0.187; the pod CIDR is 10.42.0.0/16, while the nodes sit on entirely different addresses). ONLY BECAUSE OF THAT does the podSelector in networkPolicy.ingressController match it. Switch the ingress controller to host networking and its pods share the node's network namespace. They are then not selectable as pods at all, the ingressController entry matches nothing, and EVERY WEB CHART IN THIS REPOSITORY GOES DARK AT ONCE in the restricted configuration - while every policy is still accepted and still reads as correct. The symptom to recognise is exactly that shape: all web traffic stops together and every pod stays Ready, because the probe path does not run through the controller. Nothing here can detect this and nothing here can fail usefully on it, which is the same class of dependency as --enable-certificate-owner-ref in #126. It is written here, on the thing that depends on it, so whoever changes the controller's networking meets the consequence. AND A POLICY DOES APPLY TO TRAFFIC THAT CAME THROUGH A SERVICE, which is why the ingressController rule works in the first place. A Service is only destination NAT, and the policy is evaluated at the pod's interface, so a ClusterIP exempts nothing. What the Service changes is the SOURCE ADDRESS: pod -> ClusterIP -> pod PRESERVES it, so a podSelector or a namespaceSelector can still match the sender. Traffic arriving from outside through a NodePort with the default externalTrafficPolicy: Cluster is MASQUERADED to a node, which is why such rules cannot be restricted by source at all and are left open instead. THE PORT NUMBERS HERE ARE POD PORTS, NEVER NODEPORTS. A NetworkPolicy is evaluated at the POD's network interface, after kube-proxy has already translated a NodePort to the targetPort. Writing 30080 where the pod listens on 8080 matches nothing: the object is accepted, looks strict, and blocks every inbound connection instead. ci/run-networkpolicy-test.sh asserts this mechanically - every port named here must exist as a containerPort of the pod spec this policy selects. */ -}} {{- if .Values.networkPolicy.enabled }} {{- $np := .Values.networkPolicy }} {{- $probeSources := $np.probeSources | default list }} {{- $allowedNs := $np.allowedNamespaces | default list }} {{- $ic := $np.ingressController | default dict }} {{- $routed := or .Values.ingress.enabled .Values.httpRoute.enabled }} apiVersion: networking.k8s.io/v1 kind: NetworkPolicy metadata: name: {{ .Release.Name }}-{{ .Chart.Name }}-networkpolicy labels: app: {{ .Release.Name }}-{{ .Chart.Name }}-networkpolicy spec: {{- /* Selects the Deployment's pods. A chart that keeps the StatefulSet instead has to move this selector along with the Service's, and ci/run-networkpolicy-test.sh fails if it selects no pod spec of the same render - which is the mistake that would otherwise leave a NetworkPolicy in the namespace filtering nothing at all. */}} podSelector: matchLabels: app: {{ .Release.Name }}-{{ .Chart.Name }}-deployment policyTypes: - Ingress {{- /* Egress is listed because there IS something to restrict here: this workload needs DNS and nothing else by default. A chart whose workload opens no outbound connection of its own must NOT list Egress - valkey is the example - because an egress rule that constrains nothing makes the object look stricter than it is. */}} - Egress ingress: {{- /* The http port. It is the port all three probes address, so it is the probe path, and the shape below is the whole reason networkPolicy.probeSources exists. */}} - ports: {{- range .Values.xxx.ports }} - protocol: {{ .protocol | default "TCP" }} port: {{ .containerPort }} {{- end }} {{- if $probeSources }} {{- /* RESTRICTED, because the operator supplied probeSources. The kubelet's probes come from the IP of the WORKER NODE running the pod, so that address has to be in the list or the pod never becomes Ready - and a pod that is never Ready reads as a broken application rather than as a policy. The ingress controller is added here too, or the Ingress goes dark the moment this list is filled. */}} from: - namespaceSelector: matchLabels: {{- /* Set by Kubernetes itself on every namespace (>= 1.21), so this needs no labelling work on namespaces this chart does not own. */}} kubernetes.io/metadata.name: {{ .Release.Namespace }} {{- if and $routed $ic.namespace }} {{- /* ONE from-entry with TWO selectors, which is an AND: pods carrying these labels IN that namespace. Written as two list entries it would be an OR and would open the port to the whole controller namespace - kube-system here, i.e. to everything in the cluster's own namespace. */}} - namespaceSelector: matchLabels: kubernetes.io/metadata.name: {{ $ic.namespace | quote }} {{- with $ic.podLabels }} podSelector: matchLabels: {{- toYaml . | nindent 14 }} {{- end }} {{- end }} {{- range $allowedNs }} - namespaceSelector: matchLabels: kubernetes.io/metadata.name: {{ . | quote }} {{- end }} {{- range $probeSources }} - ipBlock: cidr: {{ . | quote }} {{- end }} {{- else }} {{- /* NO "from" SELECTOR, WHICH MEANS OPEN - deliberately, and only inside the cluster, because this port carries no NodePort. The alternative was to guess the worker node CIDRs, and a wrong guess blocks every kubelet probe: the pod stays un-Ready, the rollout times out, and the cause looks like the application. Note what an EMPTY "from: []" would do instead: it also allows everything, but while looking like a restriction. Hence no key at all, and ci/run-networkpolicy-test.sh rejects the empty form. */}} {{- end }} egress: {{- /* DNS, unconditionally. There is no value to switch this off, and that is deliberate: a knob whose only other setting breaks every name lookup in the pod is a trap and not a feature. */}} - ports: - protocol: UDP port: 53 - protocol: TCP port: 53 {{- with $np.egress }} {{- with .extraPorts }} {{- /* Ports only - see note (a) in the header. Any destination. */}} - ports: {{- range . }} - protocol: TCP port: {{ int . }} {{- end }} {{- end }} {{- end }} {{- end }}