policy-webhook.yaml

# Copyright 2021 The Sigstore Authors.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

---
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: policy-webhook
  namespace: cosign-system
spec:
  selector:
    matchLabels:
      role: policy-webhook
  template:
    metadata:
      labels:
        role: policy-webhook
    spec:
      # To avoid node becoming SPOF, spread our replicas to different nodes.
      affinity:
        podAntiAffinity:
          preferredDuringSchedulingIgnoredDuringExecution:
          - podAffinityTerm:
              labelSelector:
                matchLabels:
                  role: policy-webhook
              topologyKey: kubernetes.io/hostname
            weight: 100

      serviceAccountName: webhook
      containers:
      - name: policy-webhook
        # This is the Go import path for the binary that is containerized
        # and substituted here.
        image: ko://github.com/sigstore/cosign/cmd/cosign/policy_webhook
        resources:
          requests:
            cpu: 20m
            memory: 20Mi
          limits:
            cpu: 200m
            memory: 200Mi
        env:
        - name: SYSTEM_NAMESPACE
          valueFrom:
            fieldRef:
              fieldPath: metadata.namespace
        - name: CONFIG_LOGGING_NAME
          value: config-logging
        - name: METRICS_DOMAIN
          value: sigstore.dev/policy
        - name: WEBHOOK_NAME
          value: policy-webhook

        securityContext:
          allowPrivilegeEscalation: false
          readOnlyRootFilesystem: true
          runAsNonRoot: true
          capabilities:
            drop:
            - all

        volumeMounts:
        # Failing to provide a writable $HOME can cause TUF client initialization to panic
        - mountPath: /home/nonroot
          name: writable-home-dir

        readinessProbe: &probe
          failureThreshold: 6
          initialDelaySeconds: 20
          periodSeconds: 1
          httpGet:
            scheme: HTTPS
            port: 8443
            httpHeaders:
            - name: k-kubelet-probe
              value: "policy-webhook"
        livenessProbe: *probe

      # Our webhook should gracefully terminate by lame ducking first, set this to a sufficiently
      # high value that we respect whatever value it has configured for the lame duck grace period.
      terminationGracePeriodSeconds: 300

      volumes:
      - emptyDir: {}
        name: writable-home-dir