apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: kube-cert-manager
  name: kube-cert-manager
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: kube-cert-manager
      name: kube-cert-manager
    spec:
      containers:
        - name: kube-cert-manager
          image: palmstonegames/kube-cert-manager:0.3.1
          args:
            - "-data-dir=/var/lib/cert-manager"
            - "-acme-url=https://acme-staging.api.letsencrypt.org/directory"
            # NOTE: the URL above points to the staging server, where you won't get real certs.
            # Uncomment the line below to use the production LetsEncrypt server:
            #- "-acme-url=https://acme.api.letsencrypt.org/directory"
          volumeMounts:
            - name: data
              mountPath: /var/lib/cert-manager
        - name: kubectl-proxy
          image: palmstonegames/kubectl-proxy:1.4.0
      volumes:
        - name: "data"
          gcePersistentDisk:
            pdName: kube-cert-manager
            fsType: ext4

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  labels:
    app: kube-cert-manager
  name: kube-cert-manager
spec:
  replicas: 1
  template:
    metadata:
      labels:
        app: kube-cert-manager
      name: kube-cert-manager
    spec:
      containers:
        - name: kube-cert-manager
          image: palmstonegames/kube-cert-manager:0.3.1
          args:
            - "-data-dir=/var/lib/cert-manager"
            - "-acme-url=https://acme-staging.api.letsencrypt.org/directory"
            # NOTE: the URL above points to the staging server, where you won't get real certs.
            # Uncomment the line below to use the production LetsEncrypt server:
            #- "-acme-url=https://acme-v01.api.letsencrypt.org/directory"
          volumeMounts:
            - name: data
              mountPath: /var/lib/cert-manager
        - name: kubectl-proxy
          image: palmstonegames/kubectl-proxy:1.4.0
      volumes:
        - name: "data"
          gcePersistentDisk:
            pdName: kube-cert-manager
            fsType: ext4

Correct production Let's Encrypt URL in example
Correct production Let's Encrypt URL in example

The URL in the sample deployment does not work as it is missing the '-v01' suffix.