Add documentation for HealthChecks

public-site/docs/radix-config/index.md

@@ -492,7 +492,7 @@ One exception is when the `replicas` value is set to `0` (i.e. the component is
 The previous `resources` block have been replaced by `triggers`.
 :::
 
-#### Azure Service bus
+#### `azureServiceBus` trigger
 
 Take a look here [github.com/equinor/radix-sample-keda](https://github.com/equinor/radix-sample-keda) for a sample implementation that runs on Radix.
 
@@ -511,6 +511,46 @@ Service Account: keda-operator
 #    We are hoping on improving this - https://github.com/kedacore/keda/issues/5630
 ```
 
+
+### `healthChecks`
+
+By default Radix configures a TCP Readiness probe that tells the platform your application is ready to accept traffic as soon as the port is opened.
+However it is reccommended to to configure this yourself. A HTTP Probe could inform Radix that the application with all the required backend systems (like databases or caches) is ready for work. We also support Liveness and Startup Probes.
+
+If any custom probes are configured, Radix will not include the default readiness probe and you must configure it yourself.
+
+```yaml
+spec:
+  components:
+    - name: backend
+      healthChecks:
+        startupProbe:
+          tcpSocket:
+            port: 8000
+        livenessProbe:
+          httpGet:
+            port: 8000
+            path: /healthz/live
+        readinessProbe:
+          successThreshold: 1
+          periodSeconds: 30
+          failureThreshold: 3
+          initialDelaySeconds: 10
+          timeoutSeconds: 5
+          httpGet:
+            port: 8000
+            path: /healthz/ready # Component is Ready when this endpoint returns a successful status code (2xx or 3xx)
+```
+
+All probes have all settings (except for successThreshold that is not available for liveness and startup probes). We support HTTP, TCP, Exec and GRPC probes.
+`environmentConfig` can also override individual startup, liveness or readiness-probes (but will not merge probe specific config).
+
+:::warning
+Incorrectly configured probes can lead to premature restarts and will affect your uptime.
+
+Read more about probes here: https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/
+:::
+
 ### `imageTagName`
 
 ```yaml
@@ -858,6 +898,38 @@ spec:
 
 The `horizontalScaling` field of a component environment config adds automatic scaling of the component in the environment, or it combines or overrides a component `imageTagName` if it is defined.
 
+#### `healthChecks`
+
+Health check probes defined here will override probes defined on the component level. 
+
+```yaml
+spec:
+  components:
+    - name: backend
+      healthChecks:
+        startupProbe:
+          tcpSocket:
+            port: 8000
+        livenessProbe:
+          tcpSocket:
+            port: 8000
+        readinessProbe:
+          httpGet:
+            port: 8000
+            path: /health/ready
+      environmentConfig:
+        - environment: prod
+          healthChecks:
+            livenessProbe:
+              httpGet:
+                port: 8000
+                path: /health/alive
+```
+
+In this example, the prod environment will have 3 probes, a startup probe (TCP port 8000), a liveness check (HTTP /health/ready) and a readiness probe (HTTP /health/ready)
+
+Please see more information at [`healthChecks`](#healthchecks) for detailed information and warnings.
+
 #### `imageTagName`
 
 ```yaml