dch-webhooks: Enable host provisioning feature

The *dch-webhooks* server now has a _POST /host/online_ hook that can
be triggered by a new machine when it first comes online. This hook
starts an automatic provisioning process by creating a Kubernetes Job
to run Ansible and publishing information about the host to provision
via AMQP.  Thus, the server now needs access to the Kubernetes API in
order to create the Job and access to RabbitMQ in order to publish the
task parameters.

dch-webhooks/ansible-job.yaml

@@ -0,0 +1,115 @@
+apiVersion: batch/v1
+kind: Job
+metadata:
+  generateName: host-provision-
+  labels: &labels
+    app.kubernetes.io/name: host-provisioner
+    app.kubernetes.io/component: host-provisioner
+spec:
+  backoffLimit: 0
+  template:
+    metadata:
+      labels: *labels
+    spec:
+      restartPolicy: Never
+      initContainers:
+      - name: ssh-agent
+        image: &image git.pyrocufflink.net/infra/host-provisioner
+        imagePullPolicy: Always
+        command:
+        - tini
+        - ssh-agent
+        - --
+        - -D
+        - -a
+        - /run/ssh/agent.sock
+        restartPolicy: Always
+        securityContext:
+          readOnlyRootFilesystem: true
+        volumeMounts:
+        - mountPath: /run/ssh
+          name: tmp
+          subPath: run/ssh
+      - name: ssh-add
+        image: *image
+        command:
+        - ssh-add
+        - -t
+        - 30m
+        - /run/secrets/ssh/host-provisioner.key
+        env:
+        - name: SSH_AUTH_SOCK
+          value: /run/ssh/agent.sock
+        securityContext:
+          readOnlyRootFilesystem: true
+        volumeMounts:
+        - mountPath: /run/ssh
+          name: tmp
+          subPath: run/ssh
+        - mountPath: /run/secrets/ssh
+          name: provisioner-key
+          readOnly: true
+      containers:
+      - name: host-provisioner
+        image: *image
+        env:
+        - name: SSH_AUTH_SOCK
+          value: /run/ssh/agent.sock
+        - name: AMQP_HOST
+          value: rabbitmq.pyrocufflink.blue
+        - name: AMQP_PORT
+          value: '5671'
+        - name: AMQP_CA_CERT
+          value: /run/dch-ca/dch-root-ca.crt
+        - name: AMQP_CLIENT_CERT
+          value: /run/secrets/host-provisioner/rabbitmq/tls.crt
+        - name: AMQP_CLIENT_KEY
+          value: /run/secrets/host-provisioner/rabbitmq/tls.key
+        - name: AMQP_EXTERNAL_CREDENTIALS
+          value: '1'
+        securityContext:
+          readOnlyRootFilesystem: true
+        volumeMounts:
+        - mountPath: /etc/ssh/ssh_known_hosts
+          name: ssh-known-hosts
+          subPath: ssh_known_hosts
+          readOnly: true
+        - mountPath: /home/jenkins
+          name: workspace
+        - mountPath: /run/dch-ca
+          name: dch-root-ca
+          readOnly: true
+        - mountPath: /run/ssh
+          name: tmp
+          subPath: run/ssh
+        - mountPath: /run/secrets/host-provisioner/rabbitmq
+          name: rabbitmq-cert
+          readOnly: true
+        - mountPath: /tmp
+          name: tmp
+          subPath: tmp
+      securityContext:
+        runAsNonRoot: true
+        runAsUser: 1000
+        runAsGroup: 1000
+        fsGroup: 1000
+      volumes:
+      - name: dch-root-ca
+        configMap:
+          name: dch-root-ca
+      - name: provisioner-key
+        secret:
+          secretName: provisioner-ssh-key
+          defaultMode: 0440
+      - name: ssh-known-hosts
+        configMap:
+          name: ssh-known-hosts
+      - name: rabbitmq-cert
+        secret:
+          secretName: rabbitmq-cert
+          defaultMode: 0440
+      - name: tmp
+        emptyDir:
+          medium: Memory
+      - name: workspace
+        emptyDir: {}