cert-utils-operator

Cert-utils-operator

Cert utils operator is a set of functionalities around certificates packaged in a Kubernetes operator.

Certificates are assumed to be available in a secret of type kubernetes.io/tls (other types of secrets are ignored by this operator). By convention this type of secrets have three optional entries:

1. tls.key: the private key of the certificate.
2. tls.crt: the actual certificate.
3. ca.crt: the CA bundle that validates the certificate.

The functionalities are the following:

1. Ability to populate route certificates
2. Ability to create java keystore and truststore from the certificates
3. Ability to show info regarding the certificates
4. Ability to alert when a certificate is about to expire
5. Ability to inject ca bundles in Secrets, ConfigMaps, ValidatingWebhookConfiguration, MutatingWebhookConfiguration CustomResourceDefinition and APIService objects

All these feature are activated via opt-in annotations.

Populating route certificates

This feature works on secure routes with edge or reencrypt type of termination.

This feature is activated with the following annotation on a route: cert-utils-operator.redhat-cop.io/certs-from-secret: "<secret-name>". Routes that are not secured (tls.termination field initialized to either edge or reencrypt) will be ignored even if they have the annotation.

The following fields of the route will be updated:

1. key with the content of tls.key.
2. certificate with the content of tls.crt.
3. caCertificate with the content of ca.crt.

It is possible to control whether the caCertificate field should be injected via the following annotations cert-utils-operator.redhat-cop.io/inject-CA: "[true|false]". The default is true. This can be useful if the certificate also contains the ca in ca.crt in its certificate chain. In this case the OpenShift route validation will fail.

The destinationCACertificate can also be injected. To activate this feature use the following annotation: cert-utils-operator.redhat-cop.io/destinationCA-from-secret: "<secret-name>". The following field will be updated:

1. destinationCACertificate with the content of ca.crt.

Note that the two annotations can point to different secrets.

Creating java keystore and truststore

Secrets

This feature is activated with the following annotation on a kubernetes.io/tls secret: cert-utils-operator.redhat-cop.io/generate-java-keystores: "true".

When this annotation is set two more entries are added to the secret:

1. keystore.jks: this Java keystore contains the tls.crt and tls.key certificate.
2. trustsstore.jks: this Java keystore contains the ca.crt certificate.

Note that Java Keystore require the key to be in PKCS#8 format. It is a responsibility of the certificate provisioner to make sure the key is in this format. No validation is currently performed by the cert-utils operator.

A such annotated secret looks like the following:

The default password for these keystores is changeme. The password can be changed by adding the following optional annotation: cert-utils-operator.redhat-cop.io/java-keystore-password: <password>. The alias of the certificate inside the keystore is alias.

ConfigMaps

This feature is activated with the following annotation on a configmap: cert-utils-operator.redhat-cop.io/generate-java-truststore: "true".

When this annotation is the following entry is added to the configmap as binaryData:

1. truststore.jks: this Java keystore contains the ca-bundle.crt certificate.

Note that Java Keystore require the key to be in PKCS#8 format. It is a responsibility of the certificate provisioner to make sure the key is in this format. No validation is currently performed by the cert-utils operator.

The default password for these keystores is changeit. The password can be changed by adding the following optional annotation: cert-utils-operator.redhat-cop.io/java-keystore-password: <password>. The alias of the certificate inside the keystore is alias.

Showing info on the certificates

This feature is activated with the following annotation on a kubernetes.io/tls secret: cert-utils-operator.redhat-cop.io/generate-cert-info: "true".

When this annotation is set two more entries are added to the secret:

1. tls.crt.info: this entries contains a textual representation of tls.crt the certificates in a similar notation to openssl.
2. ca.crt.info: this entries contains a textual representation of ca.crt the certificates in a similar notation to openssl.

A such annotated secret looks like the following:

Alerting when a certificate is about to expire

This operator can generate Prometheus alerts and/or Kubernetes events when a certifciate is about to expire.

Generating prometheus alerts

Prometheus alerts are generated for all certificates. In order for the certifciate metrics to be collected and the alerts be generated the Prometheus CRs deployed with this operator must be honored by a Prometheus operator. If you are running on OpenShift just add the label openshift.io/cluster-monitoring="true" to the namespace containing the operator.

The following metrics will be collected for every tls secret:

Alerts will be generated at 85% and 95% of the certifciate lifetime. Alerts are generated for all certificates including certifciate that are possibly automatically rotated. This is intentional as the automation that rotates the certificates may be non-functioning.

If these alerts are not useful in your deployment, you can be silenced them in alert-manager as described here.

Generating Kubernetes events

This feature is activated with the following annotation on a kubernetes.io/tls secret: cert-utils-operator.redhat-cop.io/generate-cert-expiry-alert: "true".

When this annotation is set the secret will generate a Kubernetes Warning Event if the certificate is about to expire.

This feature is useful when the certificates are not renewed by an automatic system.

The timing of this alerting mechanism can be controller with the following annotations:

Here is an example of a certificate soon-to-expiry event:

CA Injection

ValidatingWebhookConfiguration, MutatingWebhokConfiguration CustomResourceDefinition and APIService types of objects (and possibly in the future others) need the master API process to connect to trusted servers to perform their function. In order to do so over an encrypted connection, a CA bundle needs to be configured. In these objects the CA bundle is passed as part of the CR and not as a secret, and that is fine because the CA bundles are public info. However it may be difficult at deploy time to know what the correct CA bundle should be. Often the CA bundle needs to be discovered as a piece on information owned by some other objects of the cluster.

This feature allows you to inject the ca bundle from either a kubernetes.io/tls secret or from the service_ca.crt file mounted in every pod. The latter is useful if you are protecting your webhook with a certificate generated with the service service certificate secret feature.

This feature is activated by the following annotation:

1. cert-utils-operator.redhat-cop.io/injectca-from-secret: <secret namespace>/<secret name>

In addition to those objects, it is also possible to inject ca bundles from secrets to secrets and configmaps:

1. secrets: the secret must of type: kubernetes.io/tls. These types of secret must contain the tls.crt and tls.key keys, but is this case those keys are going to be presumably empty. So it is recommended to create these secrets as follows:

apiVersion: v1
kind: Secret
metadata:
  annotations:
    cert-utils-operator.redhat-cop.io/injectca-from-secret: test-cert-utils/test1
  name: test-inject-ca
  namespace: test-cert-utils
type: kubernetes.io/tls
stringData:
  tls.crt: ""
  tls.key: ""

1. confimaps: the ca bundle will be injected in this key ca.crt, here is an example:

apiVersion: v1
kind: ConfigMap
metadata:
  annotations:
    cert-utils-operator.redhat-cop.io/injectca-from-secret: test-cert-utils/test1
  name: test-inject-ca-cm
  namespace: test-cert-utils

Projected volumes can be used to merge the caBundle with other pieces of configuration and or change the key name.

Metrics

Prometheus compatible metrics are exposed by the Operator and can be integrated into OpenShift's default cluster monitoring. To enable OpenShift cluster monitoring, label the namespace the operator is deployed in with the label openshift.io/cluster-monitoring="true".

oc label namespace <namespace> openshift.io/cluster-monitoring="true"

Testing metrics

export operatorNamespace=cert-utils-operator-local # or cert-utils-operator
oc label namespace ${operatorNamespace} openshift.io/cluster-monitoring="true"
oc rsh -n openshift-monitoring -c prometheus prometheus-k8s-0 /bin/bash
export operatorNamespace=cert-utils-operator-local # or cert-utils-operator
curl -v -s -k -H "Authorization: Bearer $(cat /var/run/secrets/kubernetes.io/serviceaccount/token)" https://cert-utils-operator-controller-manager-metrics.${operatorNamespace}.svc.cluster.local:8443/metrics
exit

Deploying the Operator

This is a cluster-level operator that you can deploy in any namespace, cert-utils-operator is recommended.

It is recommended to deploy this operator via OperatorHub, but you can also deploy it using Helm.

Multiarch Support

Deploying from OperatorHub

Note: This operator supports being installed disconnected environments

If you want to utilize the Operator Lifecycle Manager (OLM) to install this operator, you can do so in two ways: from the UI or the CLI.

Deploying from OperatorHub UI

• If you would like to launch this operator from the UI, you'll need to navigate to the OperatorHub tab in the console. Before starting, make sure you've created the namespace that you want to install this operator to with the following:

oc new-project cert-utils-operator

• Once there, you can search for this operator by name: cert utils operator. This will then return an item for our operator and you can select it to get started. Once you've arrived here, you'll be presented with an option to install, which will begin the process.
• After clicking the install button, you can then select the namespace that you would like to install this to as well as the installation strategy you would like to proceed with (Automatic or Manual).
• Once you've made your selection, you can select Subscribe and the installation will begin. After a few moments you can go ahead and check your namespace and you should see the operator running.

Deploying from OperatorHub using CLI

If you'd like to launch this operator from the command line, you can use the manifests contained in this repository by running the following:

oc new-project cert-utils-operator

oc apply -f config/operatorhub -n cert-utils-operator

This will create the appropriate OperatorGroup and Subscription and will trigger OLM to launch the operator in the specified namespace.

Deploying with Helm

Here are the instructions to install the latest release with Helm.

oc new-project cert-utils-operator
helm repo add cert-utils-operator https://redhat-cop.github.io/cert-utils-operator
helm repo update
helm install cert-utils-operator cert-utils-operator/cert-utils-operator

This can later be updated with the following commands:

helm repo update
helm upgrade cert-utils-operator cert-utils-operator/cert-utils-operator

Development

Running the operator locally

Note: this operator build process is tested with podman, but some of the build files (Makefile specifically) use docker because they are generated automatically by operator-sdk. It is recommended remap the docker command to the podman command.

export repo=raffaelespazzoli
docker login quay.io/$repo
oc new-project cert-utils-operator
oc project cert-utils-operator
oc label namespace cert-utils-operator openshift.io/cluster-monitoring="true"
envsubst < config/local-development/tilt/env-replace-image.yaml > config/local-development/tilt/replace-image.yaml
tilt up

Test helm chart locally

Define an image and tag. For example...

export imageRepository="quay.io/redhat-cop/cert-utils-operator"
export imageTag="$(git -c 'versionsort.suffix=-' ls-remote --exit-code --refs --sort='version:refname' --tags https://github.com/redhat-cop/cert-utils-operator.git '*.*.*' | tail --lines=1 | cut --delimiter='/' --fields=3)"

Deploy chart...

make helmchart IMG=${imageRepository} VERSION=${imageTag}
helm upgrade -i cert-utils-operator-local charts/cert-utils-operator -n cert-utils-operator-local --create-namespace

Delete...

helm delete cert-utils-operator-local -n cert-utils-operator-local
kubectl delete -f charts/cert-utils-operator/crds/crds.yaml

Building/Pushing the operator image

export repo=raffaelespazzoli #replace with yours
docker login quay.io/$repo
make docker-build IMG=quay.io/$repo/cert-utils-operator:latest
make docker-push IMG=quay.io/$repo/cert-utils-operator:latest

Deploy to OLM via bundle

make manifests
make bundle IMG=quay.io/$repo/cert-utils-operator:latest
operator-sdk bundle validate ./bundle --select-optional name=operatorhub
make bundle-build BUNDLE_IMG=quay.io/$repo/cert-utils-operator-bundle:latest
docker push quay.io/$repo/cert-utils-operator-bundle:latest
operator-sdk bundle validate quay.io/$repo/cert-utils-operator-bundle:latest --select-optional name=operatorhub
oc new-project cert-utils-operator
oc label namespace cert-utils-operator openshift.io/cluster-monitoring="true"
operator-sdk cleanup cert-utils-operator -n cert-utils-operator
operator-sdk run bundle --install-mode AllNamespaces -n cert-utils-operator quay.io/$repo/cert-utils-operator-bundle:latest

Releasing

git tag -a "<tagname>" -m "<commit message>"
git push upstream <tagname>

If you need to remove a release:

git tag -d <tagname>
git push upstream --delete <tagname>

If you need to "move" a release to the current main

git tag -f <tagname>
git push upstream -f <tagname>

Cleaning up

operator-sdk cleanup cert-utils-operator -n cert-utils-operator
oc delete operatorgroup operator-sdk-og
oc delete catalogsource cert-utils-operator-catalog