Add liveness readiness check troubleshooting steps

doc/topics/autodevops/index.md

@@ -522,6 +522,40 @@ To fix your custom chart:
 You can find more information in
 [issue #263778, "Migrate PostgreSQL from stable Helm repo"](https://gitlab.com/gitlab-org/gitlab/-/issues/263778).
 
+### Error: release .... failed: timed out waiting for the condition
+
+When getting started with Auto Devops, you might encounter this error when first deploying your application:
+
+```plaintext
+INSTALL FAILED
+PURGING CHART
+Error: release staging failed: timed out waiting for the condition
+```
+
+This is most likely caused by a failed liveness/readiness probe that is automatically attempted during the deployment process. By default, these probes are run against the root page of the deployed application on port 5000. If your application isn't configured to serve anything at the root page, or is configured to run on a specific port OTHER than 5000, this check will fail. 
+
+If this is the case, you should see these failures within the events for the relevant Kubernetes namespace. These events would look similar to the following:
+
+```plaintext
+LAST SEEN   TYPE      REASON                   OBJECT                                            MESSAGE
+3m20s       Warning   Unhealthy                pod/staging-85db88dcb6-rxd6g                      Readiness probe failed: Get http://10.192.0.6:5000/: dial tcp 10.192.0.6:5000: connect: connection refused
+3m32s       Warning   Unhealthy                pod/staging-85db88dcb6-rxd6g                      Liveness probe failed: Get http://10.192.0.6:5000/: dial tcp 10.192.0.6:5000: connect: connection refused
+```
+
+To change the port used for the liveness/readiness checks, we'll need to pass [custom values to the Helm chart](https://docs.gitlab.com/ee/topics/autodevops/customize.html#customize-values-for-helm-chart) used by Auto Devops:
+
+1. Create a directory & file at the root of your repository named `.gitlab/auto-deploy-values.yaml`.
+
+1. Populate the file with the following content, replacing the port values with the actual port number your application is configured to use:
+
+   ```yaml
+   service:
+     internalPort: <port_value>
+     externalPort: <port_value>
+   ```
+1. Commit your changes.
+
+After commiting your changes, subsequent probes should use the newly defined ports. The page that's probed can also be changed, simply override the `livenessProbe.path` and `readinessProbe.path` values (shown in the [default values.yaml](https://gitlab.com/gitlab-org/cluster-integration/auto-deploy-image/-/blob/master/assets/auto-deploy-app/values.yaml)) in the same fashion.
 ## Development guides
 
 [Development guide for Auto DevOps](../../development/auto_devops.md)