New to Searchlight? Please start here.

Check cert

Check command cert checks the expiration timestamp of any certificate from Secrets. No longer you have to get a surprise that your certificates have expired.


cert check command has the following variables:

  • selector - Selector (label query) to filter on, supports ‘=’, ‘==’, and ‘!=’
  • secretName - Name of secret from where certificates are checked
  • secretKey - Name of secret key where certificates are kept
  • warning - Remaining duration for Warning state. [Default: 360h]
  • critical - Remaining duration for Critical state. [Default: 120h]

Execution of this command can result in following states:

  • OK
  • Warning
  • Critical
  • Unknown


Before You Begin

At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikube.

Now, install Searchlight operator in your cluster following the steps here.

To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial. Run the following command to prepare your cluster for this tutorial:

$ kubectl create namespace demo
namespace "demo" created

$ kubectl get namespaces
NAME          STATUS    AGE
default       Active    6h
kube-public   Active    6h
kube-system   Active    6h
demo          Active    4m

Create a Secret

In this tutorial, we are going to use onessl to issue certificates. Download onessl from kubepack/onessl.

$ onessl create ca-cert
$ onessl create server-cert

Now, we have two certificates ca.crt and server.crt.

Lets create a Secret with these Certificates.

$ kubectl create secret generic server-cert -n demo \
        --from-file=./ca.crt --from-file=./server.crt

secret "server-cert" created
$ kubectl get secret -n demo server-cert -o yaml
apiVersion: v1
kind: Secret
  name: server-cert
  namespace: demo
type: Opaque
  ca.crt: Y2EuY3J0Cg==
  server.crt: c2VydmVyLmNydAo=

Create Alert

In this tutorial, we are going to create an alert to check certificates in Secret.

$ cat ./docs/examples/cluster-alerts/cert/demo-0.yaml

kind: ClusterAlert
  name: cert-demo-0
  namespace: demo
  check: cert
    secretName: server-cert
    secretKey: "ca.crt,server.crt"
    warning: 240h
    critical: 72h
  checkInterval: 30s
  alertInterval: 2m
  notifierSecretName: notifier-config
  - notifier: Mailgun
    state: Critical
    to: [""]


  • spec.check provides check command name. In this case, it is cert.
  • spec.vars supports following variables

    • selector - Label selector for secrets where certificates are stored. Supports ‘=’, ‘==’, and ‘!=’
    • secretName - Name of secret from where certificates are checked.
    • secretKey - List of secret keys where certificates are kept
    • warning - Remaining duration for Warning state. [Default: 360h]
    • critical - Remaining duration for Critical state. [Default: 120h]
$ kubectl apply -f ./docs/examples/cluster-alerts/cert/demo-0.yaml
clusteralert "cert-demo-0" created

$ kubectl describe clusteralert cert-demo-0 -n demo
Name:		cert-demo-0
Namespace:	demo
Labels:		<none>
  FirstSeen	LastSeen	Count	From			SubObjectPath	Type		Reason		Message
  ---------	--------	-----	----			-------------	--------	------		-------
  9s		9s		1	Searchlight operator			Normal		SuccessfulSync	Applied ClusterAlert: "cert-demo-0"

Voila! cert command has been synced to Icinga2. Please visit here to learn how to configure notifier secret. Now, open IcingaWeb2 in your browser. You should see a Icinga host demo@cluster and Icinga service ca-cert-demo-0.

Following notes are important:

  • If secretName and selector both are not provided, all secrets in same namespace will be checked.
  • If secretKey is not provided in the alert, and SecretType of a secret is SecretTypeTLS, TLS certificate in tls.crt" will be checked.

Cleaning up

To cleanup the Kubernetes resources created by this tutorial, run:

$ kubectl delete ns demo

If you would like to uninstall Searchlight operator, please follow the steps here.

Next Steps

  • To periodically run various checks on nodes in a Kubernetes cluster, use NodeAlerts.
  • To periodically run various checks on pods in a Kubernetes cluster, use PodAlerts.
  • See the list of supported notifiers here.
  • Wondering what features are coming next? Please visit here.
  • Want to hack on Searchlight? Check our contribution guidelines.

Take your team where it needs to go.

Create your cluster in minutes. Our team is here to help and would be happy to chat with you.