cert-manager-webhook-gandi

command module
Version: v0.1.1 Latest Latest
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Published: Feb 26, 2020 License: Apache-2.0 Imports: 17 Imported by: 0

README

ACME webhook for Gandi (cert-manager-webhook-gandi)

cert-manager-webhook-gandi is an ACME webhook for cert-manager. It provides an ACME (read: Let's Encrypt) webhook for cert-manager, which allows to use a DNS-01 challenge with Gandi. This allows to provide Let's Encrypt certificates to Kubernetes for service protocols other than HTTP and furthermore to request wildcard certificates. Internally it uses the Gandi LiveDNS API to communicate with Gandi.

Quoting the ACME DNS-01 challenge:

This challenge asks you to prove that you control the DNS for your domain name by putting a specific value in a TXT record under that domain name. It is harder to configure than HTTP-01, but can work in scenarios that HTTP-01 can’t. It also allows you to issue wildcard certificates. After Let’s Encrypt gives your ACME client a token, your client will create a TXT record derived from that token and your account key, and put that record at _acme-challenge.<YOUR_DOMAIN>. Then Let’s Encrypt will query the DNS system for that record. If it finds a match, you can proceed to issue a certificate!

Building

Build the container image cert-manager-webhook-gandi:latest:

make build

Image

Ready made images are hosted on Docker Hub (browse). Use at your own risk:

bwolf/cert-manager-webhook-gandi
Release History

Refer to the ChangeLog file.

Compatibility

This webhook has been tested with cert-manager v0.13.1 and Kubernetes v0.17.x on amd64. In theory it should work on other hardware platforms as well but no steps have been taken to verify this. Please drop me a note if you had success.

Testing with Minikube

  1. Build this webhook in Minikube:

     minikube start --memory=4G --more-options
     eval $(minikube docker-env)
     make build
     docker images | grep webhook
    
  2. Install cert-manager with Helm:

     kubectl create namespace cert-manager
     kubectl apply --validate=false -f https://raw.githubusercontent.com/jetstack/cert-manager/v0.13.1/deploy/manifests/00-crds.yaml
    
     helm repo add jetstack https://charts.jetstack.io
     helm install cert-manager --namespace cert-manager \
         --set 'extraArgs={--dns01-recursive-nameservers=8.8.8.8:53\,1.1.1.1:53}' \
         jetstack/cert-manager
    
     kubectl get pods --namespace cert-manager --watch
    

    Note: refer to Name servers in the official documentation according the extraArgs.

    Note: ensure that the custom CRDS of cert-manager match the major version of the cert-manager release by comparing the URL of the CRDS with the helm info of the charts app version:

         helm search repo jetstack
    

    Example output:

         NAME                    CHART VERSION   APP VERSION     DESCRIPTION
         jetstack/cert-manager   v0.13.1         v0.13.1         A Helm chart for cert-manager
    

    Check the state and ensure that all pods are running fine (watch out for any issues regarding the cert-manager-webhook- pod and its volume mounts):

         kubectl describe pods -n cert-manager | less
    
  3. Create the secret to keep the Gandi API key in the default namespace, where later on the Issuer and the Certificate are created:

     kubectl create secret generic gandi-credentials \
         --from-literal=api-token='<GANDI-API-KEY>'
    

    Note: See RBAC Authorization:

    A Role can only be used to grant access to resources within a single namespace.

    As far as I understand cert-manager, the Secret must reside in the same namespace as the Issuer and Certificate resource.

  4. Grant permission for the service-account to access the secret holding the Gandi API key:

     kubectl apply -f rbac.yaml
    
  5. Deploy this webhook (add --dry-run to try it and --debug to inspect the rendered manifests; Set logLevel to 6 for verbose logs):

     helm install cert-manager-webhook-gandi \
         --namespace cert-manager \
         --set image.repository=cert-manager-webhook-gandi \
         --set logLevel=2 \
         ./deploy/cert-manager-webhook-gandi
    

    Check the logs

         kubectl get pods -n cert-manager --watch
         kubectl logs -n cert-manager cert-manager-webhook-gandi-XYZ
    
  6. Create a staging issuer (email addresses with the suffix example.com are forbidden):

     cat << EOF | sed "s/invalid@example.com/$email/" | kubectl apply -f -
      apiVersion: cert-manager.io/v1alpha2
      kind: Issuer
      metadata:
        name: letsencrypt-staging
        namespace: default
      spec:
        acme:
          # The ACME server URL
          server: https://acme-staging-v02.api.letsencrypt.org/directory
          # Email address used for ACME registration
          email: invalid@example.com
          # Name of a secret used to store the ACME account private key
          privateKeySecretRef:
            name: letsencrypt-staging
          solvers:
          - dns01:
              webhook:
                groupName: acme.bwolf.me
                solverName: gandi
                config:
                  apiKeySecretRef:
                    key: api-token
                    name: gandi-credentials
     EOF
    

    Check status of the Issuer:

     kubectl describe issuer letsencrypt-staging
    

    Note: The production Issuer is similar.

  7. Issue a Certificate for your $DOMAIN (documentation):

     cat << EOF | sed "s/example-com/$DOMAIN/" | kubectl apply -f -
     apiVersion: cert-manager.io/v1alpha2
     kind: Certificate
     metadata:
       name: example-com
     spec:
       dnsNames:
       - example-com
       issuerRef:
         name: letsencrypt-staging
       secretName: example-com-tls
     EOF
    

    Check the status of the Certificate:

     kubectl describe certificate $DOMAIN
    
  8. Issue a wildcard Certificate for your $DOMAIN:

     cat << EOF | sed "s/example-com/$DOMAIN/" | kubectl apply -f -
     apiVersion: cert-manager.io/v1alpha2
     kind: Certificate
     metadata:
       name: wildcard-example-com
     spec:
       dnsNames:
       - '*.example-com'
       issuerRef:
         name: letsencrypt-staging
       secretName: wildcard-example-com-tls
     EOF
    

    Check the status of the Certificate:

     kubectl describe certificate $DOMAIN
    
  9. Uninstall this webhook:

    helm uninstall cert-manager-webhook-gandi --namespace cert-manager
    kubectl delete -f rbac.yaml
    kubectl delete gandi-credentials
    
  10. Uninstalling cert-manager: This is out of scope here. Refer to the official documentation.

Development

Note: If some tool (IDE or build process) fails resolving a dependency, it may be the cause that a indirect dependency uses bzr for versioning. In such a case it may help to put the bzr binary into $PATH or $GOPATH/bin.

Release process

  • Code changes result in a new image version and Git tag
  • Helm chart changes result in a new chart version
  • All other changes are pushed to master

Conformance test

Please note that the test is not a typical unit or integration test. Instead it invokes the web hook in a Kubernetes-like environment which asks the web hook to really call the DNS provider (.i.e. Gandi). It attempts to create an TXT entry like cert-manager-dns01-tests.example.com, verifies the presence of the entry via Google DNS. Finally it removes the entry by calling the cleanup method of web hook.

Note: Replace the string darwin in the URL below with an OS matching your system (e.g. linux).

As said above, the conformance test is run against the real Gandi API. Therefore you must have a Gandi account, a domain and an API key.

cp testdata/gandi/api-key.yaml.sample testdata/gandi/api-key.yaml
echo -n $YOUR_GANDI_API_KEY | base64 | pbcopy # or xclip
$EDITOR testdata/gandi/api-key.yaml
./scripts/fetch-test-binaries.sh
TEST_ZONE_NAME=example.com. go test -v .

Documentation

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There is no documentation for this package.

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