WordPress on GKE Autopilot

WordPress is the world's most popular content management system, powering over 43% of all websites globally. This module deploys WordPress on GKE Autopilot on top of the App_GKE foundation, which provisions and manages the shared Google Cloud and Kubernetes infrastructure.

This guide focuses on the cloud services WordPress uses and how to explore and operate them from the Google Cloud Console and the command line. For the mechanics that are common to every GKE application — Workload Identity, ingress, autoscaling, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC Service Controls, backups, and the deployment lifecycle — refer to the App_GKE foundation guide rather than repeating them here.

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1. Overview

WordPress runs as a PHP/Apache web workload. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	PHP/Apache pods, 1 vCPU / 2 GiB by default, horizontally autoscaled
Database	Cloud SQL for MySQL 8.0	Required — WordPress does not support PostgreSQL
Shared files	Filestore (NFS)	wp-content directory (uploads, plugins, themes) shared across all replicas
Object storage	Cloud Storage	A dedicated wp-uploads media bucket
Cache	Redis	Optional object cache; enabled by default to reduce database load
Secrets	Secret Manager	Auto-generated database password and eight WordPress authentication keys and salts
Ingress	Cloud Load Balancing	External LoadBalancer, optional custom domain + managed certificate

Sensible defaults worth knowing up front:

• MySQL 8.0 is mandatory. The database engine is fixed; selecting PostgreSQL or NONE breaks startup.
• NFS is required for a functional site. WordPress stores uploaded media, installed plugins, and active themes under wp-content/. Without a shared NFS volume, each pod has an isolated and ephemeral wp-content — plugins are lost on restart and replicas serve different versions of the site.
• Eight WordPress authentication keys and salts are auto-generated and stored in Secret Manager; you never set them in plain text.
• Redis object cache is enabled by default. Reduces database load by caching the results of expensive queries. Requires a Redis host to be reachable (defaults to the NFS server IP when redis_host is left empty).
• Session affinity is ClientIP. WordPress uses PHP sessions for the admin panel; requests from a browser must be pinned to one pod.
• The startup probe is TCP, not HTTP. WordPress may not yet respond to HTTP requests during database initialisation on first boot; a TCP probe only checks that Apache's port is open.

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2. Google Cloud Services & How to Explore Them

All commands assume you have run gcloud container clusters get-credentials <cluster> --region <region> --project <project> and that PROJECT, REGION, and NAMESPACE are set. The namespace and other identifiers are reported in the deployment Outputs.

A. GKE Autopilot — the WordPress workload

WordPress pods are scheduled on Autopilot, which bills for the CPU/memory the pods actually request. Horizontal Pod Autoscaling sizes the deployment between the minimum and maximum replica counts.

• Console: Kubernetes Engine → Workloads → select the WordPress workload to see pods, revisions, and events. Kubernetes Engine → Services & Ingress shows the external IP.
• CLI:

  kubectl get pods,svc,hpa -n "$NAMESPACE"
  kubectl logs -n "$NAMESPACE" deploy/<service-name> --tail=100
  kubectl describe hpa -n "$NAMESPACE"          # current vs target utilisation

See App_GKE for how Autopilot, scaling, and the workload type (Deployment vs StatefulSet) are managed.

B. Cloud SQL for MySQL 8.0

WordPress stores all site data (posts, users, settings, comments) in a managed Cloud SQL for MySQL 8.0 instance. Pods reach it privately through the Cloud SQL Auth Proxy sidecar over a Unix socket, so no public IP is exposed. On first deploy an initialisation Job creates the application database and user.

• Console: SQL → select the instance for connections, backups, flags, and metrics.
• CLI:

  gcloud sql instances list --project "$PROJECT"
  gcloud sql instances describe <instance-name> --project "$PROJECT"
  # Open an interactive shell to inspect schema/data:
  gcloud sql connect <instance-name> --user=<db-user> --project "$PROJECT"

The instance name, database name, user, and the Secret Manager secret holding the password are all surfaced in the Outputs. For the connection model, automated backups, and password rotation, see App_GKE.

C. Filestore (NFS) and Cloud Storage

WordPress's wp-content directory is mapped onto a Filestore (NFS) share mounted into every pod so all replicas share the same plugins, themes, and uploaded media. A dedicated Cloud Storage bucket (wp-uploads) is also provisioned for media assets; the workload service account is granted access automatically.

• Console: Filestore → Instances for the NFS share; Cloud Storage → Buckets for the media bucket.
• CLI:

  gcloud filestore instances list --project "$PROJECT"
  gcloud storage buckets list --project "$PROJECT"
  gcloud storage ls gs://<media-bucket>/          # bucket name is in the Outputs
  # Confirm the NFS share is mounted inside a pod:
  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- df -h | grep -i nfs
  # Confirm PHP limits (useful for diagnosing upload failures):
  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- php -r "
    echo 'memory_limit: ' . ini_get('memory_limit') . PHP_EOL;
    echo 'upload_max_filesize: ' . ini_get('upload_max_filesize') . PHP_EOL;
    echo 'post_max_size: ' . ini_get('post_max_size') . PHP_EOL;
  "

See App_GKE for NFS provisioning, GCS Fuse, and CMEK options.

D. Redis object cache

Redis backs WordPress's object cache via the WP Redis plugin, storing the results of expensive database queries in memory and dramatically reducing page load times and database load on busy sites. When redis_host is left empty and NFS is enabled, the NFS server IP is used as the Redis endpoint (the default shared deployment model).

• Console: Memorystore → Redis (if using a managed instance).
• CLI:

  redis-cli -h <redis-host> ping        # from a host with network access
  redis-cli -h <redis-host> info keyspace
  # From inside a WordPress pod:
  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- \
    sh -c 'redis-cli -h $WP_REDIS_HOST -p $WP_REDIS_PORT ping'

E. Secret Manager

The WordPress database password and the eight WordPress authentication keys and salts are stored as Secret Manager secrets and injected into pods at runtime; plaintext values never appear in configuration or Terraform state.

• Console: Security → Secret Manager.
• CLI:

  gcloud secrets list --project "$PROJECT"
  # List all secrets belonging to this deployment:
  gcloud secrets list --project "$PROJECT" --filter="name~<resource-prefix>"
  gcloud secrets versions access latest --secret=<secret-name> --project "$PROJECT"

The database password secret name is in the Outputs. See App_GKE for the Secret Store CSI integration and rotation.

F. Networking & ingress

By default the workload is exposed through an external Cloud Load Balancing IP. A custom domain with a Google-managed certificate can be enabled, and a static IP can be reserved so the address survives redeploys.

• Console: Network services → Load balancing; VPC network → IP addresses.
• CLI:

  kubectl get ingress,svc -n "$NAMESPACE"
  gcloud compute addresses list --project "$PROJECT"

See App_GKE for custom domains, Cloud CDN, and static IP details.

G. Cloud Logging & Monitoring

Pod stdout/stderr flow to Cloud Logging; GKE and Cloud SQL metrics flow to Cloud Monitoring. Optional uptime checks and alert policies are available.

• Console: Logging → Logs Explorer; Monitoring → Dashboards / Alerting.
• CLI:

  gcloud logging read 'resource.type="k8s_container" AND resource.labels.namespace_name="'"$NAMESPACE"'"' \
    --project "$PROJECT" --limit 50

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3. WordPress Application Behaviour

• First-deploy database setup. An initialisation Job using the mysql:8.0-debian image creates the WordPress database and user and grants privileges before the application starts. It runs on every tofu apply because it is idempotent — it safely skips steps that are already complete.

• Authentication keys and salts. Eight 64-character WordPress security secrets (auth key, secure auth key, logged-in key, nonce key, and their corresponding salts) are generated automatically on first deploy and stored in Secret Manager. Rotating these secrets immediately invalidates all active browser sessions — every logged-in user will be signed out.

• PHP configuration baked at build time. php_memory_limit, upload_max_filesize, and post_max_size are applied to the container image at Cloud Build time. Changing them triggers a new image build and rolling update.

• WordPress table prefix. WORDPRESS_TABLE_PREFIX is set to wp_ automatically. Override via environment_variables only when migrating an existing database with a non-standard prefix.

• Probe behaviour. The startup probe uses TCP (port open check) rather than HTTP to avoid failures during WordPress's database initialisation phase. The liveness probe polls /wp-admin/install.php — which returns HTTP 200 whether WordPress is freshly installed or already configured — with a 300-second initial delay to allow the db-init job to complete. Do not reduce failure_threshold below 10 for the startup probe on production deployments.

• WP_HOME and WP_SITEURL. On GKE the service URL is not known at plan time, so these constants are not auto-set. WordPress discovers the site URL from the database on first setup. Set WP_HOME via environment_variables if you need to force a specific URL before WordPress has been installed.

• Scheduled tasks. WordPress's built-in wp-cron pseudo-cron relies on site traffic to trigger. For production sites with consistent uptime requirements, disable wp-cron in wp-config.php and schedule wp cron event run --due-now as a cron_jobs entry.

  Inspect scheduled tasks:

  kubectl get cronjobs -n "$NAMESPACE"
  kubectl get jobs -n "$NAMESPACE" --sort-by=.metadata.creationTimestamp

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4. Configuration Variables

Variables are grouped exactly as they appear on the deployment platform. Only settings specific to or notable for WordPress are listed; every other input is inherited from App_GKE with its standard behaviour and defaults.

Group 1 — Project & Identity

Variable	Default	Description
project_id	(required)	Target Google Cloud project.
region	us-central1	Region for the workload and regional resources.

Group 2 — Deployment Environment

Variable	Default	Description
tenant_deployment_id	demo	Short suffix that makes resource names unique per environment.
support_users	[]	Emails granted project access and monitoring alerts.
resource_labels	{}	Labels applied to all resources for cost/ownership tracking.

Group 3 — Application Identity

Variable	Default	Description
application_name	wordpress	Base name for resources. Do not change after first deploy.
application_display_name	Wordpress	Friendly name shown in the Console.
application_description	Wordpress CMS on GKE	Workload description annotation.
application_version	latest	WordPress image version tag passed as APP_VERSION build argument. Use a pinned version (e.g. 6.7.1) in production for reproducible builds.
php_memory_limit	512M	PHP memory_limit baked into the container image at build time. Increase for heavy plugin workloads (e.g. WooCommerce, Elementor).
upload_max_filesize	64M	Maximum size of a single file upload. Must be ≤ post_max_size.
post_max_size	64M	Maximum size of all POST data in a single HTTP request. Must be ≥ upload_max_filesize.

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
cpu_limit	1000m	CPU per pod; 1 vCPU is sufficient for typical sites.
memory_limit	2Gi	Memory per pod; 2 GiB recommended for WordPress with plugins.
min_instance_count	1	Minimum replicas. Keep ≥ 1 to avoid cold-start latency.
max_instance_count	1	Maximum replicas. Increase only after verifying all installed plugins handle concurrent pod access correctly.
container_port	80	WordPress/Apache listens on port 80.
enable_cloudsql_volume	true	Cloud SQL Auth Proxy sidecar for socket connections. Required.
enable_vertical_pod_autoscaling	false	Let Autopilot tune resource requests automatically.

Group 5 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra non-secret settings. WORDPRESS_TABLE_PREFIX, WORDPRESS_DEBUG, and Redis vars are set automatically.
secret_environment_variables	{}	Map of env var → Secret Manager secret name. Eight WordPress auth secrets are injected automatically.

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	LoadBalancer	How the Service is exposed.
session_affinity	ClientIP	Sticky routing required for WordPress PHP sessions in the admin panel.
workload_type	null	Auto-resolves to StatefulSet when per-pod storage is enabled.
network_tags	['nfsserver']	Node/pod tags; nfsserver is required for NFS connectivity.

Group 7 — StatefulSet

Variable	Default	Description
stateful_pvc_enabled	null	Enable per-pod PVCs when using StatefulSet.
stateful_pvc_size	10Gi	Storage size per PVC. WordPress media libraries grow quickly — plan for 50–200 GiB on active sites.
stateful_pvc_mount_path	/data	Container path for the per-pod PVC.
stateful_pvc_storage_class	standard-rwo	Kubernetes StorageClass for PVCs.

Group 8 — Resource Quota

Variable	Default	Description
enable_resource_quota	false	Cap namespace CPU/memory/object counts.
quota_memory_requests / quota_memory_limits	""	Must use binary units (4Gi, 8192Mi) — bare integers are read as bytes and block all scheduling.

Group 9 — Reliability Policies

Variable	Default	Description
enable_pod_disruption_budget	false	Protect availability during node upgrades. The default is false because the default max_instance_count is 1; enable only when running multiple replicas.
pdb_min_available	1	Raise min_instance_count above 1 to leave eviction headroom.
enable_topology_spread	false	Spread pods across zones for multi-replica deployments.

Group 10 — Observability & Health

Variable	Default	Description
startup_probe	TCP, 30s delay, threshold 20	TCP probe on port 80 — avoids HTTP failures during database initialisation on first boot. Do not reduce failure_threshold below 10.
liveness_probe	HTTP /wp-admin/install.php, 300s delay	HTTP probe; 300-second initial delay accommodates the db-init job.
uptime_check_config	disabled	Optional Cloud Monitoring uptime check.
alert_policies	[]	Optional metric alert policies.

Group 11 — Jobs & Scheduled Tasks

Variable	Default	Description
initialization_jobs	[]	Leave empty to use the built-in db-init job. Supplying a non-empty list replaces the default entirely.
cron_jobs	[]	Recurring scheduled tasks. Use to replace wp-cron with a dedicated schedule for reliable WordPress cron execution.

Group 12 — CI/CD & GitHub Integration

Standard App_GKE Cloud Build / Cloud Deploy integration — see App_GKE. Key inputs: enable_cicd_trigger, github_repository_url, github_token, enable_cloud_deploy.

Group 13 — Filesystem (NFS)

Variable	Default	Description
enable_nfs	true	Shared Filestore volume for WordPress wp-content (keep enabled).
nfs_mount_path	/mnt/nfs	Mount path inside the container. The startup script symlinks wp-content here.

Group 14 — Cloud Storage & Artifact Registry

Variable	Default	Description
create_cloud_storage	true	Provision the wp-uploads media bucket.
storage_buckets	[{name_suffix="data"}]	Additional buckets.
gcs_volumes	[]	GCS Fuse mounts.
manage_storage_kms_iam / enable_artifact_registry_cmek	false	CMEK options.

Group 15 — Redis Cache

Variable	Default	Description
enable_redis	true	Use Redis for WordPress object caching.
redis_host	""	Leave empty to use the NFS server IP (default shared model); set explicitly for a dedicated Memorystore instance.
redis_port	6379	Redis port.
redis_auth	""	Optional Redis auth password (sensitive).

Group 16 — Database Backend

Variable	Default	Description
database_type	null (resolved to MYSQL_8_0 by Wordpress_Common)	Fixed — do not change. WordPress requires MySQL.
application_database_name	wp	Database name. Immutable after first deploy.
application_database_user	wp	Application user. Immutable after first deploy.
database_password_length	32	Generated password length (16–64).
enable_auto_password_rotation	false	Zero-downtime DB password rotation.

Group 17 — Backup & Maintenance

Variable	Default	Description
backup_schedule	0 2 * * *	Automated backup cron (UTC).
backup_retention_days	7	Retention; raise to 30–90 for production/compliance.
enable_backup_import / backup_source / backup_file / backup_format	restore options	Restore from a backup on deploy. Note: this module uses backup_file (filename within the GCS backup bucket), not backup_uri.

Group 18 — Custom SQL Scripts

enable_custom_sql_scripts, custom_sql_scripts_bucket, custom_sql_scripts_path, custom_sql_scripts_use_root — run SQL from a GCS bucket after provisioning. See App_GKE.

Group 19 — Custom Domain, Static IP & Networking

Variable	Default	Description
enable_custom_domain	true	Provision Ingress for custom hostnames + managed certificate.
application_domains	[]	Hostnames to serve.
reserve_static_ip	true	Stable external IP across redeploys.

Group 20 — Identity-Aware Proxy (IAP)

Variable	Default	Description
enable_iap	false	Require Google sign-in in front of WordPress.
iap_authorized_users / iap_authorized_groups	[]	Who may access.
iap_oauth_client_id / iap_oauth_client_secret	""	Required when IAP is enabled (sensitive).
iap_support_email	""	Shown on the OAuth consent screen.

Group 21 — Cloud Armor

Variable	Default	Description
enable_cloud_armor	false	Attach a Cloud Armor (WAF) policy to the Ingress backend. Strongly recommended — WordPress login pages are prime targets for brute-force attacks.
admin_ip_ranges	[]	CIDRs allowed privileged access.
cloud_armor_policy_name	default-waf-policy	Policy name.

Group 22 — VPC Service Controls & Audit Logging

Variable	Default	Description
enable_vpc_sc	false	Enforce a VPC-SC perimeter (requires organization_id).
vpc_cidr_ranges / vpc_sc_dry_run	(set)	Access level CIDRs / dry-run mode.
enable_audit_logging	false	Detailed Cloud Audit Logs.

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5. Outputs

These values are returned on a successful deployment and are the quickest way to locate and explore the running resources.

Output	Description
service_name	Kubernetes Service name.
namespace	Namespace the workload runs in.
service_cluster_ip	In-cluster ClusterIP.
stage_service_cluster_ips	Map of ClusterIPs for Cloud Deploy stage services.
service_external_ip	External LoadBalancer IP (when a static IP is reserved).
service_url	URL to reach WordPress.
database_instance_name	Cloud SQL instance name.
database_name	Application database name.
database_user	Application database user.
database_password_secret	Secret Manager secret holding the DB password.
database_host / database_port	DB endpoint (127.0.0.1 via the Auth Proxy) / port.
storage_buckets	Created Cloud Storage buckets.
network_name / network_exists / regions	VPC network, presence, available regions.
container_image / container_registry	Deployed image and Artifact Registry repo.
monitoring_enabled / monitoring_notification_channels	Monitoring status and channels.
initialization_jobs / db_import_job	Names of the setup and (optional) import jobs.
deployment_id / tenant_id / resource_prefix	Naming identifiers.
project_id / project_number	Project identifiers.
cicd_enabled / github_repository_url / github_repository_owner / github_repository_name / cicd_configuration	CI/CD status and details.
artifact_registry_repository / cloudbuild_trigger_name / cloudbuild_trigger_id	Registry and build trigger.
kubernetes_ready	Whether the cluster/workload is ready. On a first apply of a new inline cluster this is false — run apply a second time to complete the deployment.
vpc_sc_enabled / vpc_sc_perimeter_name / vpc_sc_dry_run_mode	VPC-SC status.
audit_logging_enabled / artifact_registry_cmek_enabled	Audit logging and CMEK status.

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6. Configuration Pitfalls & Sensible Defaults

Risk: Critical (data loss / outage / security) — High (service degraded) — Medium (cost or partial degradation) — Low (minor).

Setting	Sensible value	Risk	Consequence if wrong
database_type	MYSQL_8_0 (auto-set)	Critical	WordPress requires MySQL; PostgreSQL/NONE breaks startup.
enable_nfs	true	Critical	Without shared storage, plugins/themes/uploads are isolated per pod and lost on restart; multi-replica deployments serve inconsistent site versions.
application_database_name / _user	set once	Critical	Immutable after first deploy; renaming recreates the DB/user and destroys all WordPress data.
enable_backup_import	false unless restoring	Critical	Enabling without a valid backup_file in the GCS bucket fails the import job.
quota_memory_requests / _limits	binary units	Critical	Bare integers are bytes and block all scheduling.
container_image_source	custom	High	The custom WordPress image wires the NFS symlink and Cloud SQL socket. Using prebuilt with the vanilla WordPress image breaks Cloud SQL socket connectivity.
nfs_mount_path	/mnt/nfs (do not change after deploy)	High	The startup script symlinks wp-content to this path; changing it after initial deployment breaks the symlink.
memory_limit	2Gi	High	WordPress with popular plugins (WooCommerce, Elementor) requires at least 2 GiB; insufficient memory causes PHP fatal errors.
session_affinity	ClientIP	High	Without stickiness, admin users are logged out on every request that lands on a different pod.
enable_redis	true	Medium	With multiple replicas, isolated per-pod in-memory caches cause redundant database queries.
redis_host	"" (NFS IP) or explicit	High	No valid Redis endpoint if Redis is on, NFS is off, and no host is set.
enable_cloud_armor	enable for public sites	High	WordPress login pages (/wp-login.php, xmlrpc.php) are prime brute-force targets.
php_memory_limit	512M	Medium	Must be within memory_limit; too low causes plugin activation failures and white screens of death.
min_instance_count	1	Medium	0 causes 30–60 second cold starts and potential visible errors for the first visitor after idle.
backup_retention_days	7 (raise for prod)	Medium	Too short for e-commerce or content-heavy sites; one week of posts/orders lost.
stateful_pvc_size	10Gi (raise for prod)	Medium	WordPress media libraries grow quickly; plan for 50–200 GiB for active sites.
enable_network_segmentation	enable for shared clusters	Medium	Without NetworkPolicy, any pod in the cluster can reach WordPress pods directly.
pdb_min_available vs min_instance_count	leave headroom	Medium	1/1 can stall node upgrades (single pod cannot be evicted).

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For the foundation behaviour referenced throughout — IAM and Workload Identity, autoscaling, ingress and certificates, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC-SC, backups, and image mirroring — see App_GKE. WordPress-specific application configuration shared with the Cloud Run variant is described in Wordpress_Common.