Authentik on GKE Autopilot

authentik (goauthentik.io) is an open-source (MIT, open-core) identity provider: single sign-on via OIDC and SAML, LDAP and SCIM, multi-factor authentication, and proxy authentication — a self-hosted alternative to Okta, Auth0, and Keycloak. This module deploys authentik 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 authentik 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.

---

1. Overview

authentik runs as a Python/Django Deployment on GKE Autopilot, with its background worker (ak worker) co-located in the same pod container. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	Deployment, 2 vCPU / 4 GiB by default, 1–5 replicas
Database	Cloud SQL for PostgreSQL 15	Required — authentik needs PostgreSQL ≥ 14; MySQL is blocked
Cache & queue	None — no Redis	authentik ≥ 2025.10 moved cache, sessions, task queue, and the WebSocket channel layer into PostgreSQL
Media storage	Cloud Storage (GCS Fuse CSI)	Bucket mounted at /media for uploaded icons and flow backgrounds
Secrets	Secret Manager	Stable AUTHENTIK_SECRET_KEY, akadmin bootstrap password, database password
Image	Artifact Registry + Cloud Build	Thin custom build FROM ghcr.io/goauthentik/server (cloud entrypoint + worker launcher)
Ingress	Cloud Load Balancing	External LoadBalancer Service; optional custom domain + managed certificate

Sensible defaults worth knowing up front:

• PostgreSQL 15 is mandatory and is the only datastore. No Redis, no search backend — sessions, cache, and the task queue all live in Cloud SQL.
• The worker is co-located. The container entrypoint starts ak worker in the background next to the server (the same pattern as Chatwoot's Sidekiq worker) — no separate worker Deployment. Keep min_instance_count ≥ 1 so the worker is always processing.
• max_instance_count = 5. authentik is stateless across pods — all state is in PostgreSQL — so multiple replicas (each with its own worker) are safe.
• AUTHENTIK_SECRET_KEY is generated automatically and stored in Secret Manager. It must remain stable — rotating it invalidates all sessions and makes encrypted fields unreadable. Both secret names are simple (__-free), so they pass the GKE SecretSync targetKey validation; the AUTHENTIK_POSTGRESQL__* mapping happens inside the entrypoint from the injected DB_* variables.
• The akadmin admin account is bootstrapped on first boot with bootstrap_email (default admin@techequity.cloud) and a Secret Manager-backed password. Bootstrap variables apply on the first boot only.
• application_version = "latest" is pinned. authentik publishes no latest tag on GHCR; the build pins latest to a known-good release (2026.5.4) via the app-specific AUTHENTIK_VERSION build ARG.
• Migrations run automatically at startup, guarded by a PostgreSQL advisory lock so concurrent pods don't collide — no separate migrate job.
• Health endpoints are unauthenticated: startup GET /-/health/ready/, liveness GET /-/health/live/.

---

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 authentik workload

authentik pods are scheduled on Autopilot, which bills for the CPU/memory the pods request. Horizontal Pod Autoscaling sizes the Deployment between the minimum and maximum replica counts. Each pod runs the server, the background worker, and the Cloud SQL Auth Proxy sidecar.

• Console: Kubernetes Engine → Workloads → select the authentik workload for 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> -c <app-container> --tail=100
  kubectl describe hpa -n "$NAMESPACE"

See App_GKE for Autopilot, scaling, and workload-type management.

B. Cloud SQL for PostgreSQL 15

authentik stores everything here — users, groups, flows, providers, sessions, cache, and the background task queue. Pods reach the instance privately through the Cloud SQL Auth Proxy sidecar; the container entrypoint maps the injected DB_* variables onto authentik's AUTHENTIK_POSTGRESQL__* convention and sets the SSL mode by connection type — disable for the proxy sidecar's loopback TCP (127.0.0.1 / localhost; the proxy is TLS-terminated but does not speak SSL itself, so requiring SSL there fails with "server does not support SSL, but SSL was required"), require only for direct TCP to any other host. On first deploy a single db-init Job creates the tenant-scoped database and role.

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

  gcloud sql instances list --project "$PROJECT"
  gcloud sql instances describe <instance-name> --project "$PROJECT"
  gcloud sql connect <instance-name> --user=<db-user> --database=<db-name> --project "$PROJECT"

The instance name, database, user, and password secret are in the Outputs (database and user names are tenant-prefixed). See App_GKE for the connection model, backups, and password rotation.

C. Cloud Storage — media

A dedicated bucket is mounted at /media via the GCS Fuse CSI driver for uploaded media (application icons, flow backgrounds), so uploads survive pod replacement and scaling.

• Console: Cloud Storage → Buckets.
• CLI:

  gcloud storage buckets list --project "$PROJECT"
  gcloud storage ls gs://<media-bucket>/        # bucket name is in the Outputs

D. Secret Manager

Two authentik secrets are generated automatically:

• AUTHENTIK_SECRET_KEY — signs sessions/cookies and derives internal encryption. Never rotate it.

• AUTHENTIK_BOOTSTRAP_PASSWORD — the initial akadmin password, applied on first boot only.

• Console: Security → Secret Manager.

• CLI:

  gcloud secrets list --project "$PROJECT" --filter="name~authentik"
  gcloud secrets versions access latest --secret=<secret-name> --project "$PROJECT"

See Authentik_Common for the full secret model and App_GKE for SecretSync details.

E. Networking & ingress

By default the workload is exposed through an external LoadBalancer IP; a custom domain with a Google-managed certificate can be enabled, and a static IP is reserved by default so the address survives redeploys. For an IdP a stable, TLS-fronted hostname matters — the OIDC/SAML redirect URIs you register in client applications must match the URL users reach authentik on.

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

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

F. Cloud Logging & Monitoring

Server and worker logs both flow to Cloud Logging (they share the container's stdout/stderr). GKE and Cloud SQL metrics flow to Cloud Monitoring.

• 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

---

3. authentik Application Behaviour

• First-deploy database setup. A single initialization Job runs db-init.sh using postgres:15-alpine: it waits for PostgreSQL, creates the tenant-scoped role and database, grants privileges, defensively grants cloudsqlsuperuser, and signals the proxy sidecar to shut down so the Job completes. Idempotent and safe to re-run.
• Self-migrating startup. authentik's server runs its own Django migrations on every startup, guarded by a PostgreSQL advisory lock so concurrent pods don't collide. There is no separate migrate job. The first boot runs the full suite — expect several minutes before /-/health/ready/ returns 200; the startup probe allows ~11 minutes.
• First login. Sign in as akadmin using the bootstrap_email value and the password in the ...-bootstrap-password secret. If the bootstrap variables were absent on the first boot, complete setup at <service-url>/if/flow/initial-setup/ instead.
• Applications and providers are configured in-app after deploy. OIDC/SAML providers, applications, outposts, and flows are authentik configuration, not Terraform inputs — create them in the Admin interface (<service-url>/if/admin/) once the workload is ready.
• Worker co-location. ak worker runs in the same container as the server; its log lines are interleaved in the pod logs (kubectl logs ... | grep -i worker). Keep min_instance_count ≥ 1 so scheduled tasks and outpost sync keep processing.
• Health endpoints.

  curl -s "$SERVICE_URL/-/health/ready/" -o /dev/null -w '%{http_code}\n'   # 200 = migrated + DB reachable
  curl -s "$SERVICE_URL/-/health/live/"  -o /dev/null -w '%{http_code}\n'   # 200 = process alive

• Inspect job execution:

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

---

4. Configuration Variables

Variables are grouped exactly as they appear on the deployment platform. Only settings specific to or notable for authentik 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.
bootstrap_email	admin@techequity.cloud	Email of the built-in akadmin account, set on first boot.
bootstrap_password	"" (auto-generated)	Initial akadmin password. First boot only; stored in Secret Manager.

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.

Group 3 — Application Identity

Variable	Default	Description
application_name	authentik	Base name for resources (namespace, secrets, buckets). Do not change after first deploy.
application_display_name	authentik Identity Provider	Human-readable name.
application_version	latest	authentik version tag; latest is pinned to 2026.5.4 at build time (no upstream latest tag). Pin explicitly in production.

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
container_image_source	custom	Thin wrapper image built via Cloud Build (adds the cloud entrypoint + worker launcher).
min_instance_count	1	Keep ≥ 1 so the co-located worker keeps processing.
max_instance_count	5	Safe to raise — authentik is stateless across pods.
container_port	9000	authentik's HTTP port (Service exposes 80).
container_resources	2000m / 4Gi	Shared by server + worker; the Autopilot default gives migration headroom.
enable_cloudsql_volume	true	Auth Proxy sidecar — keep true on GKE.
enable_image_mirroring	true	GHCR base image is mirrored into Artifact Registry.

Group 5 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra AUTHENTIK_* settings (e.g. email/SMTP: AUTHENTIK_EMAIL__HOST, …). Do not set AUTHENTIK_SECRET_KEY or AUTHENTIK_POSTGRESQL__* here.
secret_environment_variables	{}	Map of env var → Secret Manager secret name. Keys must be __-free (SecretSync CRD).

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	LoadBalancer	External IP for browser SSO and OAuth callbacks.
workload_type	Deployment (auto)	authentik is stateless; StatefulSet is unnecessary.
session_affinity	ClientIP	Sticky routing helps the admin UI's WebSocket connections.
termination_grace_period_seconds	60	Grace for in-flight worker tasks on shutdown.

Group 8 — Resource Quota

Variable	Default	Description
enable_resource_quota	false	When enabling, size requests ≥ 2× one pod and use binary memory suffixes ("8Gi").

Group 9 — Reliability Policies

Variable	Default	Description
enable_pod_disruption_budget	true	Protects login availability during node upgrades.
pdb_min_available	1	Minimum pods during voluntary disruptions.

Group 10 — Observability & Health

Variable	Default	Description
startup_probe	HTTP /-/health/ready/, 60s delay, 40×15s	Unauthenticated. Generous threshold for first-boot migrations (~11 min budget).
liveness_probe	HTTP /-/health/live/, 60s delay, 3×30s	Unauthenticated process-alive check.
uptime_check_config	disabled	Optional Cloud Monitoring uptime check (point it at /-/health/live/).

Group 11 — Jobs & Scheduled Tasks

Variable	Default	Description
initialization_jobs	[]	Leave empty to use the built-in single db-init job.
cron_jobs	[]	Not needed — the co-located worker runs authentik's scheduled tasks.
additional_services	[]	Use for extra outposts (e.g. LDAP/RADIUS) if required.

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, enable_binary_authorization.

Group 13 — Filesystem (NFS)

Variable	Default	Description
enable_nfs	true	Optional; authentik keeps media on GCS, not NFS.
nfs_mount_path	/opt/authentik/storage	Mount path inside the container.

Group 14 — Cloud Storage & Artifact Registry

Variable	Default	Description
create_cloud_storage	true	The /media bucket is declared by Authentik_Common.
gcs_volumes	[]	Extra GCS Fuse mounts; /media is added automatically.
max_images_to_retain / delete_untagged_images / image_retention_days	(set)	Artifact Registry cleanup policy.

Group 15 — Redis

Variable	Default	Description
enable_redis	false	Inert. authentik ≥ 2025.10 removed Redis entirely; main.tf pins enable_redis = false.

Group 16 — Database Backend

Variable	Default	Description
database_type	POSTGRES_15	authentik requires PostgreSQL — MySQL values are rejected by validation.
application_database_name	authentik	Database base name (tenant-prefixed at deploy). Immutable after first deploy.
application_database_user	authentik	Application DB user base name (tenant-prefixed).
database_password_length	32	Generated password length (16–64).

Group 17 — Backup & Maintenance

Variable	Default	Description
backup_schedule	0 2 * * *	Automated backup cron (UTC).
backup_retention_days	7	Retention; raise for production/compliance.
enable_backup_import / backup_source / backup_uri / backup_format	restore options	Restore from a backup on deploy.

Group 19 — Custom Domain, Static IP & Networking

Variable	Default	Description
enable_custom_domain	true	Ingress + managed certificate for custom hostnames.
application_domains	[]	Hostname(s) to serve. Register OIDC redirect URIs against the domain users actually reach.
reserve_static_ip	true	Stable external IP across redeploys — important for DNS-pinned IdP hostnames.

Group 20 — Identity-Aware Proxy (IAP)

Variable	Default	Description
enable_iap	false	IAP in front of an IdP double-gates every login and breaks OAuth/SAML callbacks — leave off unless you know you need it.

Group 21 — Cloud Armor

Variable	Default	Description
enable_cloud_armor	false	WAF policy on the Ingress backend — recommended for a public IdP.
admin_ip_ranges	[]	CIDRs allowed privileged access.

Group 22 — VPC Service Controls & Audit Logging

Variable	Default	Description
enable_vpc_sc	false	Enforce a VPC-SC perimeter (requires organization_id).
enable_audit_logging	false	Detailed Cloud Audit Logs.

---

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 stage-specific services.
service_external_ip	External LoadBalancer IP.
service_url	URL to reach authentik.
database_instance_name	Cloud SQL instance name.
database_name / database_user	Application database name / user (tenant-prefixed).
database_password_secret	Secret Manager secret holding the DB password.
database_host / database_port	DB endpoint / port.
storage_buckets	Created Cloud Storage buckets (includes the /media bucket).
network_name / network_exists / regions	VPC network, presence, 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 / cicd_configuration / github_repository_*	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.
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.

---

6. Configuration Pitfalls & Sensible Defaults

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

Inherited plan-time validation. This module passes its configuration through the App_GKE foundation engine, which validates values and combinations at plan time — invalid configuration fails the plan with a clear, named error before any resource is created, so most mistakes below are caught up front rather than at apply or runtime.

Setting	Sensible value	Risk	Consequence if wrong
AUTHENTIK_SECRET_KEY (auto-generated)	Never rotate	Critical	Rotating it invalidates all active sessions and makes encrypted fields (stored credentials, tokens) unreadable.
database_type	POSTGRES_15	Critical	MySQL is blocked by validation — authentik requires PostgreSQL ≥ 14.
application_database_name / application_database_user	Set once	Critical	Immutable after first deploy; renaming recreates the DB/user and destroys all identity data.
Worker listen ports (entrypoint-managed)	Leave the entrypoint's AUTHENTIK_LISTEN__* loopback defaults	Critical	The co-located ak worker also starts an HTTP listener and inherits the server's default 0.0.0.0:9000; if it wins the bind race it answers every route — health endpoints included — with empty 200s: a blank UI while the kubelet probes look green. The entrypoint pins the worker to loopback ports (127.0.0.1:9001/9444/9301) so the server owns :9000 — a 200 with an empty body means the wrong process answered.
min_instance_count	≥ 1	High	0 is invalid semantics for the co-located worker — background tasks and outpost sync stop; outpost WebSockets disconnect.
secret_environment_variables keys	Simple, __-free names	High	The SecretSync CRD rejects keys with __ (e.g. AUTHENTIK_POSTGRESQL__PASSWORD) at apply time — that mapping belongs in the entrypoint, not a synced secret.
startup_probe.path	/-/health/ready/ (unauthenticated)	Medium	Pointing the probe at an authenticated page returns 401/403 to the kubelet — the pod never becomes ready even though authentik booted fine.
bootstrap_password / bootstrap_email	Set before first deploy	Medium	Applied on the first boot only. Changing them later has no effect — manage akadmin in-app, or use /if/flow/initial-setup/ if bootstrap vars were absent on first boot.
application_version	Pin a release	Medium	latest is silently pinned to 2026.5.4; an explicit pin makes upgrades deliberate. Nonexistent tags fail the Cloud Build with MANIFEST_UNKNOWN.
quota_memory_requests / _limits	Binary units (8Gi), ≥ 2× one pod	Critical	Bare integers are bytes and block all pod scheduling; quota sized to one pod deadlocks rolling updates.
environment_variables → AUTHENTIK_POSTGRESQL__*	Leave unset	Medium	The entrypoint maps the injected DB_* values; hardcoding short DB names authenticates as a non-existent role (names are tenant-prefixed).
enable_iap	false	Medium	IAP double-gates every login and breaks OAuth/SAML callbacks from external parties.
enable_pod_disruption_budget	true	Medium	Disabling allows GKE to evict all pods simultaneously during maintenance — a full login outage.

---

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. authentik-specific application configuration shared with the Cloud Run variant is described in Authentik_Common.