HealthCheck

Cloudders Health Check operator supports custom resource definition called HealthCheck. Its used to create uptime/health checks against external and internal services.

The current supported protocol is only HTTP(S). More will come with future releasases.

Example HTTP health check

In the below example we will create a simple HealthCheck that searches for a string on this documentation page:

kubectl apply -f - <<EOF
apiVersion: check.cloudders.com/v1alpha1
kind: HealthCheck
metadata:
  name: cloudders-docs-configuration
spec:
  testInterval: 60
  http:
    url: "https://cloudders.com/docs/configuration/notificationrule"
    searchFor:
      string: "on this documentation page"
EOF

Example TCP health check

In the below example we will create a simple HealthCheck that probes TCP service on port 8080:

kubectl apply -f - <<EOF
apiVersion: check.cloudders.com/v1alpha1
kind: HealthCheck
metadata:
  name: service-8080
spec:
  testInterval: 60
  tcp:
    ipv4: "127.0.0.1"
    port: 8080
EOF

After the HealthCheck is applied with kubectl we can see the results with the following command:

kubectl get healthchecks

And the command will print the current running HealthCheck resources in the namespace:

NAMESPACE   NAME                           URL                                                         TEST INTERVAL   LAST CHECKED           HEALTHY   RESPONSE TIME   SEARCH TYPE   SEARCH FOR
cloudders   cloudders-docs-configuration   https://cloudders.com/docs/configuration/notificationrule   60              2023-07-14T07:14:46Z   true       234ms           string        on this documentation page

The HealthCheck also supports SSL certificate expiration monitoring when used against https targets. Check the Fields section for configuration details.

Fields

Below is a table of all fields supported by the HealthCheck CRD under spec:

Field name	Type	Example	Description
http/tcp	Section	http: or tcp:	Type of the HealthCheck which we are creating. The CRD supports TCP and HTTP health checks with the relevant fields.
url:	String for http:	https://cloudders.com	Destination URL against which we run our HealthCheck. It supports http and https schema for now. You can use external and internal URLs like the one in the example, or like for internally exposed Kubernetes service: http://my-microservice.my-awesome-product:8080
testInterval:	Integer	60	Value in seconds. testIntervals lower than 30 seconds can cause the HealthCheck to be rate limited from the destination service.
sslCheck:	Section for http:		Under this Section we set our search expiration value in days
expiration:	Integer for http:	10	Monitor for SSL certificate expiration in days
searchFor:	Section for http:		Under this Section we set our search expressions or strings
string:	String for http:	operator	Simple string value which we search for in the response body
expression:	String for http:	\w{1}perato\w{1}	Fully compatible PCRE regular expression for matching output in the response body
ipv4:	String for tcp:	127.0.0.1 or FQDN	Your IPv4 address or FQDN hostname.
port:	Integer	8080	Port which we are going to probe against. It should be not open and not filtered.