ClassicPress on GKE Autopilot — Lab Guide

Overview

Estimated time: 45–90 minutes

ClassicPress is a free, open-source, business-focused CMS — a lightweight fork of WordPress 4.9.x that preserves the classic (pre-Gutenberg) editing experience, with plugins, themes, a media library, and a REST API. This lab takes you through the full operational lifecycle of the ClassicPress on GKE Autopilot module on Google Cloud: deploy it, access and verify it, run it day-to-day, observe it, diagnose common problems, and tear it down.

The lab focuses on operating the GKE module and the Google Cloud platform, not on ClassicPress product features. For the complete list of provisioned services and every configuration input (organised by group), see the Configuration Guide — this lab deliberately does not duplicate that detail so it stays accurate over time.

Objectives

By the end of this lab you will be able to:

Deploy the module from the RAD platform and locate the resources it provisions.
Connect to the GKE cluster and complete the first-run ClassicPress installer.
Perform day-2 operations — inspect, scale, update, and manage secrets and storage.
Understand how the StatefulSet PVC provides the persistence Cloud Run lacks.
Observe the workload with Cloud Logging and Cloud Monitoring.
Diagnose and resolve the most common deployment and runtime issues.
Tear the deployment down cleanly.

Prerequisites

Services_GCP deployed in the target project (provides the VPC, GKE Autopilot cluster, Cloud SQL, Artifact Registry, and shared service accounts this module depends on).
A Google Cloud project with billing enabled.
gcloud CLI and kubectl installed; gcloud auth login and gcloud auth application-default login completed.
Project Owner (or equivalent) IAM on the project.
RAD platform access with permission to deploy modules into the project.

Set these shell variables once; every task below reuses them:

export PROJECT="<your-gcp-project-id>"
export REGION="us-central1"           # the region you deploy into

Task 1 — Deploy the module [Automated]

Click Deploy in the RAD platform top navigation, open ClassicPress (GKE) from the Platform Modules list to start configuration, set project_id, and review the inputs. Configure only what you need — the Configuration Guide documents every input by group, with defaults. Review the estimated cost (if credits are enabled) and click Deploy, which opens the deployment status page with real-time logs.
The platform builds a thin custom image (FROM classicpress/classicpress) via Cloud Build, deploys the workload into the GKE Autopilot cluster as a StatefulSet with a per-pod 10Gi standard-rwo block PVC mounted at /var/www/html, provisions a Cloud SQL for MySQL 8.0 database with its Secret Manager secrets (CLASSICPRESS_SALT_SEED and the database password), a Filestore (NFS) instance (enable_nfs = true by default), a classicpress-uploads Cloud Storage bucket, and runs a one-shot database-initialisation job (db-init) that creates the application database and user. First deploys take roughly 20–35 minutes (Cloud SQL creation dominates).

Connect to the cluster and discover the namespace with name-agnostic filters:

CLUSTER=$(gcloud container clusters list --project="$PROJECT" --format="value(name)" --limit=1)
gcloud container clusters get-credentials "$CLUSTER" --region="$REGION" --project="$PROJECT"

NS=$(kubectl get ns -o name | grep classicpress | head -1 | cut -d/ -f2)
echo "Cluster: $CLUSTER   Namespace: $NS"
kubectl get all -n "$NS"

Task 2 — Access & verify [Manual]

Confirm the workload is running and find its external address:

kubectl get statefulset,pods,svc,pvc -n "$NS"
EXTERNAL_IP=$(kubectl get svc -n "$NS" \
  -o jsonpath='{.items[?(@.spec.type=="LoadBalancer")].status.loadBalancer.ingress[0].ip}')
echo "External IP: $EXTERNAL_IP"

Confirm the service is reachable:

curl -s -o /dev/null -w "%{http_code}\n" "http://${EXTERNAL_IP}/"
# expect 200 (already installed) or 302 (redirect to the first-run installer)

Open http://${EXTERNAL_IP} in a browser. On a fresh database, ClassicPress redirects to /wp-admin/install.php — complete the installer (site title, admin username, password, and email) to create the schema and the admin account. There is no pre-seeded admin credential in Secret Manager; the installer is the only way to set one. Because the install lives on the StatefulSet PVC (not ephemeral container storage), it persists across pod restarts once created.
Log in at http://${EXTERNAL_IP}/wp-login.php with the account you just created and confirm the dashboard loads.

Task 3 — Operate & keep it running (Day-2) [Manual]

Inspect the workload — StatefulSet, pods, and the PVC:

kubectl get statefulset,pods,pvc -n "$NS"
kubectl describe statefulset -n "$NS"

Scale by changing the min/max instance inputs and clicking Update on the deployment details page — the module owns the workload spec, so scaling is a configuration change, not a manual kubectl scale (a manual edit would be reverted on the next apply). Keep max_instance_count = 1: stateful_pvc_enabled = true gives each StatefulSet pod its own PVC, so a second replica would run its own separate, unsynced copy of the install rather than sharing one.
Update the application version by changing the version input in the RAD platform and applying it via Update; a new image builds and a rolling update replaces the pod. NFS-backed apps normally use Recreate deployment strategy on this foundation, but ClassicPress's primary persistence here is the PVC, not NFS — confirm the rollout completes cleanly:
```
kubectl rollout status statefulset/<service-name> -n "$NS"
```

Manage secrets and storage:

kubectl get secrets -n "$NS"
gcloud secrets list --project="$PROJECT" --filter="name~classicpress"
kubectl get jobs -n "$NS"          # db-init job

Open a database session for inspection or maintenance:

INSTANCE=$(gcloud sql instances list --project="$PROJECT" --format="value(name)" --limit=1)
gcloud sql connect "$INSTANCE" --user=classicpress --project="$PROJECT"

Why this variant does not hit the Cloud Run media-persistence bug. The ClassicPress_Common Dockerfile and entrypoint.sh never reference any NFS or Foundation-level mount path — that fact is identical on both platforms. On Cloud Run, the confirmed bug is that /var/www/html (where the upstream entrypoint writes wp-config.php and copies the whole application, including wp-content/uploads) sits on ephemeral, per-instance storage with no volume covering it, so scale-to-zero cold starts lose uploaded media and admin-installed plugins/themes. On GKE, the Application module (not the Common layer) separately sets stateful_pvc_enabled = true with stateful_pvc_mount_path = /var/www/html — the exact directory the entrypoint populates — so the install (code, plugins, themes, and uploads) persists across pod restarts and rescheduling by construction. enable_nfs = true is still the default here too, mounting Filestore at /var/lib/classicpress, a path this layer still never uses — treat it as spare, currently-unused shared storage, not the thing making persistence work.

Task 4 — Observe: Logging & Monitoring [Manual]

Logs — from kubectl or the Logs Explorer:
```
kubectl logs -n "$NS" statefulset/<service-name> --tail=50
```
Logs Explorer filter: resource.type="k8s_container" AND resource.labels.namespace_name="<namespace>".
Monitoring — open the GKE / Kubernetes dashboards and review pod CPU and memory utilisation, restart counts, and request metrics. Also check PVC usage under Kubernetes Engine → Storage as the media library grows. The module can provision an uptime check (when enabled); review Monitoring → Uptime checks and Alerting → Policies.

Task 5 — Troubleshoot & debug [Manual]

Durable techniques for the failure modes you are most likely to hit. These are platform-level diagnostics and do not change with ClassicPress releases.

Pod not Ready / CrashLoopBackOff: inspect events and logs. The startup probe is TCP on port 80 with a generous failure_threshold = 20, allowing time for the upstream entrypoint to populate an empty PVC on first boot; the liveness probe is HTTP GET / with a 300-second initial delay.
```
kubectl describe pod -n "$NS" <pod>          # Events section shows scheduling/probe/mount errors
kubectl logs -n "$NS" <pod> --previous       # logs from the crashed container
```
Site re-shows the first-run installer unexpectedly: on this variant, the install lives on the StatefulSet PVC, so this should not happen from ordinary pod restarts — if it does, check whether the PVC was recreated (a deleted/replaced PVC loses the whole install, including wp-config.php) rather than assuming it is the same cold-start bug documented for Cloud Run:
```
kubectl get pvc -n "$NS"
kubectl describe pvc -n "$NS" <pvc-name>
```
Database connection errors: confirm the Cloud SQL instance is RUNNABLE, and that the db-init job completed. Pods reach Cloud SQL through the Auth Proxy sidecar on 127.0.0.1:3306 (enable_cloudsql_volume = true, required on GKE) — no public IP is exposed.

Initialisation job failed: inspect the job and its pod logs:

kubectl get jobs -n "$NS"
kubectl logs -n "$NS" job/<job-name>

Pending pod / no external IP: check kubectl describe pod events for resource or quota issues (including the SSD_TOTAL_GB quota the default standard-rwo PVC draws from), and confirm the LoadBalancer Service has an assigned IP.
Image pull errors: confirm the image exists in Artifact Registry and the node service account can pull it.

See the Configuration Guide's Configuration Pitfalls & Sensible Defaults section for setting-specific gotchas (including the critical rule never to rotate CLASSICPRESS_SALT_SEED after first boot, and the stateful_pvc_storage_class SSD-vs-HDD quota trade-off).

Task 6 — Tear down [Automated]

On the Deployments page, open the deployment and click the Trash icon (Delete). Delete runs terraform destroy and is irreversible (the deployment record is retained for history). If a deployment is stuck and the RAD platform can no longer manage it (for example after manual changes that conflict with the Terraform state), use Purge instead — it removes the deployment from RAD's records without destroying the cloud resources (it makes RAD forget the project). This removes everything the module created — the Kubernetes workload, namespace, and PVC, Cloud SQL database, Secret Manager secrets, Filestore instance, GCS bucket, and Artifact Registry images. Resources owned by Services_GCP (the VPC, GKE cluster, shared Cloud SQL, registry) are managed separately and are not removed here.

Summary

Task	Type	Outcome
1 — Deploy	Automated	Module deploys the GKE StatefulSet + PVC, Cloud SQL (MySQL 8.0), Filestore, secrets, storage bucket, and runs `db-init`
2 — Access & verify	Manual	Connect to the cluster; reachability check passes; complete the first-run installer to create the admin account
3 — Operate	Manual	Inspect the StatefulSet/PVC, scale, update version, manage secrets/storage, DB access; understand why the PVC avoids the Cloud Run persistence bug
4 — Observe	Manual	Query Cloud Logging; review Cloud Monitoring metrics and PVC usage
5 — Troubleshoot	Manual	Diagnose pod, database, init-job, scheduling, and image-pull issues
6 — Tear down	Automated	Delete (Trash) removes all module resources

By Dr Shiyghan Emmanuel Navti · Google Cloud certified: ACE · PCA · PCD · PDE · PSE · CDL

Overview​

Objectives​

Prerequisites​

Task 1 — Deploy the module [Automated]​

Task 2 — Access & verify [Manual]​

Task 3 — Operate & keep it running (Day-2) [Manual]​

Task 4 — Observe: Logging & Monitoring [Manual]​

Task 5 — Troubleshoot & debug [Manual]​

Task 6 — Tear down [Automated]​

Summary​