Unleash on GKE Autopilot

Unleash is an open-source, Apache-2.0-licensed feature-flag and toggle-management platform for progressive delivery, A/B testing, and gradual rollouts. This module deploys Unleash 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 Unleash 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

Unleash runs as a Node.js web workload. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	Node.js pods, 1 vCPU / 512 MiB by default, horizontally autoscaled
Database	Cloud SQL for PostgreSQL 15	Required — Unleash does not support MySQL or other engines
Secrets	Secret Manager	Auto-generated bootstrap admin API token (INIT_ADMIN_API_TOKENS); database password
Ingress	Cloud Load Balancing	External LoadBalancer, optional custom domain + managed certificate

Sensible defaults worth knowing up front:

• PostgreSQL 15 is mandatory. The database engine is fixed by the shared application layer; selecting any other engine breaks startup.
• Unleash is stateless. All flag, toggle, strategy, segment, and audit data lives in PostgreSQL, so workload_type = Deployment, session_affinity = None, and any pod can serve any request. NFS and object storage are disabled.
• No Redis or queue backend. Unleash needs no cache or queue; it scales horizontally by pointing more pods at the same database.
• INIT_ADMIN_API_TOKENS is generated automatically and stored in Secret Manager, materialised into the namespace via the Secret Store CSI driver. Unleash seeds this all-access (*:*) admin API token into its database at first boot.
• Minimum 1 replica is maintained (min_instance_count = 1; GKE does not support scale-to-zero) so the Unleash API stays reachable for SDK clients.
• DATABASE_URL is assembled at pod start from the platform-injected DB_* variables. On GKE the cloud-sql-proxy sidecar listens on 127.0.0.1 with TLS already terminated, so the entrypoint uses the loopback path (SSL off toward loopback).
• The health endpoint is /health — a public, unauthenticated 200 endpoint. The Admin API under /api/admin/* requires a token.

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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 Unleash workload

Unleash 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 Unleash 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 are managed.

B. Cloud SQL for PostgreSQL 15

Unleash stores all application data (projects, feature flags, strategies, segments, API tokens, users, and the change/audit log) in a managed Cloud SQL for PostgreSQL 15 instance. Pods reach it privately through the Cloud SQL Auth Proxy sidecar; no public IP is exposed. On first deploy an initialization Job creates the application database and user, and Unleash applies its own schema migrations on startup.

• 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"
  gcloud sql connect <instance-name> --user=<db-user> --database=<db-name> --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. Secret Manager

A bootstrap admin API token is generated automatically and stored in Secret Manager, materialised into the namespace as INIT_ADMIN_API_TOKENS via the Secret Store CSI driver. The database password is managed separately by the foundation.

• Console: Security → Secret Manager.
• CLI:

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

See App_GKE for the Secret Store CSI integration and rotation.

D. 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.

E. 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. Unleash Application Behaviour

• First-deploy database setup. An initialization Job runs create-db-and-user.sh using postgres:15-alpine. It connects through the Cloud SQL Auth Proxy and idempotently creates the application database and user and grants privileges. The job is safe to re-run; it does not create tables.
• Schema migrations on start. Unleash applies its own schema migrations automatically on every startup, so upgrading the application version applies schema changes without a separate migration step.
• DATABASE_URL is composed at runtime. The custom image entrypoint assembles the connection string from the injected DB_* variables and uses the cloud-sql-proxy loopback path on GKE. Inspect the injected variables when debugging:

  POD=$(kubectl get pods -n "$NAMESPACE" -o jsonpath='{.items[0].metadata.name}')
  kubectl get pod "$POD" -n "$NAMESPACE" -o jsonpath='{.spec.containers[0].env[*].name}' | tr ' ' '\n' | grep -iE 'DB_|DATABASE'

• Bootstrap admin API token. INIT_ADMIN_API_TOKENS seeds an all-access (*:*) admin API token at first boot so CI, the Unleash CLI, and SDK back ends can call the Admin API without a UI login.
• Default UI credentials. The admin UI ships a well-known first-run account — admin / unleash4all. Change the password immediately after the first login.
• Webhook / SDK reachability. The default service_type = LoadBalancer exposes an external IP for SDK clients and CI. Set a custom domain via application_domains and reserve a static IP so the address survives redeploys.
• Health path. Startup and liveness probes target /health — a public, unauthenticated endpoint that responds 200 only when the server is initialised and connected to PostgreSQL.

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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 Unleash 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.

Group 3 — Application Identity

Variable	Default	Description
application_name	unleash	Base name for resources. Do not change after first deploy.
application_display_name	Unleash	Human-readable name shown in the Console.
application_version	5.7.0	unleashorg/unleash-server image tag; latest is remapped to a pinned tag at build time.
deploy_application	true	Set false to provision infrastructure only.

Group 4 — Runtime & Scaling

Variable	Default	Description
container_image_source	custom	Cloud Build wraps unleashorg/unleash-server with the DATABASE_URL entrypoint.
container_resources	{ cpu_limit="1000m", memory_limit="512Mi" }	Per-pod CPU/memory; Unleash's lightweight footprint.
container_port	4242	Unleash listens on port 4242.
min_instance_count	1	HPA minReplicas; keep ≥ 1 (GKE has no scale-to-zero).
max_instance_count	10	HPA maxReplicas.
workload_type	Deployment	Stateless — no StatefulSet needed.
enable_cloudsql_volume	true	Cloud SQL Auth Proxy sidecar for connectivity.
enable_image_mirroring	true	Mirror the built image into Artifact Registry.

Group 5 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra non-secret settings. DATABASE_URL is assembled at runtime — do not set it here.
secret_environment_variables	{}	Map of env var → Secret Manager secret name.
secret_propagation_delay	30	Seconds to wait after secret creation before proceeding.
secret_rotation_period	2592000s	Secret Manager rotation notification frequency.

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	LoadBalancer	How the Kubernetes Service is exposed.
session_affinity	None	Stateless — any pod serves any request; no stickiness needed.
namespace_name	""	Leave empty to auto-generate.
network_tags	[]	Node/pod network tags for firewall rules.
termination_grace_period_seconds	30	Seconds to wait after SIGTERM before SIGKILL.
enable_network_segmentation	false	Create Kubernetes NetworkPolicy resources.

Group 7 — StatefulSet

Not used for Unleash (stateless). stateful_pvc_enabled defaults null; leave the StatefulSet inputs at their defaults.

Group 8 — Resource Quota

Variable	Default	Description
enable_resource_quota	false	Create a namespace ResourceQuota.
quota_memory_requests / quota_memory_limits	""	Must use binary suffixes (4Gi, 8192Mi) — bare integers are bytes and block scheduling.

Group 9 — Reliability Policies

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

Group 10 — Observability & Health

Variable	Default	Description
startup_probe_config	HTTP /health, 30s delay, 30 retries	Startup probe. Headroom for first-boot migrations.
health_check_config	HTTP /health, 30s delay	Liveness probe.
uptime_check_config	{ enabled=false, path="/health" }	Cloud Monitoring uptime check; disabled by default.
alert_policies	[]	Metric alert policies.

Group 11 — Jobs & Scheduled Tasks

Variable	Default	Description
initialization_jobs	[]	Leave empty to use the built-in db-init job.
cron_jobs	[]	Scheduled Kubernetes CronJobs.
additional_services	[]	Sidecar or helper services deployed alongside Unleash.

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	false	NFS is off — Unleash is stateless.
nfs_mount_path	/mnt/nfs	Mount path inside the container (unused by default).

Group 14 — Cloud Storage & Artifact Registry

Variable	Default	Description
create_cloud_storage	true	Create additional GCS buckets.
storage_buckets	[]	Empty — Unleash is stateless.
gcs_volumes	[]	GCS Fuse volume mounts via the CSI driver.
manage_storage_kms_iam / enable_artifact_registry_cmek	false	CMEK options.
max_images_to_retain / delete_untagged_images / image_retention_days	(set)	Artifact Registry cleanup policy.

Group 16 — Database Backend

Variable	Default	Description
database_type	POSTGRES	Unleash requires PostgreSQL; Unleash_Common provisions PostgreSQL 15.
application_database_name	unleash	PostgreSQL database name. Immutable after first deploy.
application_database_user	unleash	Application database user. Immutable after first deploy.
database_password_length	32	Generated password length (16–64).
enable_auto_password_rotation	false	Zero-downtime DB password rotation.
rotation_propagation_delay_sec	90	Seconds to wait after rotation before rolling-restarting pods.

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)

Warning: Enabling IAP requires Google identity authentication for all inbound requests, including token-authenticated SDK and CI calls to the Unleash API. Only enable IAP when the API does not need to be reached directly by SDK clients.

Variable	Default	Description
enable_iap	false	Require Google sign-in in front of Unleash.
iap_authorized_users / iap_authorized_groups	[]	Who may access.
iap_oauth_client_id / iap_oauth_client_secret	""	Required when IAP is enabled (sensitive).

Group 21 — Cloud Armor

Variable	Default	Description
enable_cloud_armor	false	Attach a Cloud Armor (WAF) policy to the Ingress backend.
admin_ip_ranges	[]	CIDRs allowed privileged access.
cloud_armor_policy_name	default-waf-policy	Policy name.
enable_cdn	false	Enable Cloud CDN on the GKE Ingress backend.

Group 22 — VPC Service Controls & Audit Logging

Variable	Default	Description
enable_vpc_sc	false	Enforce a VPC-SC perimeter (auto-discovers 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_external_ip	External LoadBalancer IP (when a static IP is reserved).
service_url	URL to reach Unleash.
database_instance_name	Cloud SQL instance name.
database_name / database_user	Application database name / user.
database_password_secret	Secret Manager secret holding the DB password.
storage_buckets	Created Cloud Storage buckets (empty for Unleash).
container_image	Deployed image.
cicd_enabled / github_repository_url	CI/CD status and connected repo.
kubernetes_ready	Whether the cluster/workload is ready.
deployment_id / project_id	Naming and project identifiers.

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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).

Inherited plan-time validation. This module passes its configuration through the App_GKE foundation engine, which validates values and combinations at plan time — a read replica without its primary, IAP with no authorized identities, a gen1 runtime with NFS/GCS mounts, a database_type that does not match an enabled extension, an out-of-range backup_retention_days. 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
database_type	POSTGRES (→ PostgreSQL 15)	Critical	Any other engine breaks Unleash startup — it only supports PostgreSQL.
application_database_name / application_database_user	Set once	Critical	Immutable after first deploy; renaming recreates the DB/user and destroys all flag data.
enable_backup_import	false unless restoring	Critical	Enabling without a valid backup_file fails the import job.
startup_probe_config / health_check_config path	/health	High	Pointing a probe at /api/admin/* returns 401/403 and the pod never becomes Ready.
min_instance_count	1	High	GKE requires min ≥ 1; the validation guard rejects invalid values. Keeping 1 keeps the API reachable.
enable_cloudsql_volume	true	High	The Auth Proxy sidecar is required for PostgreSQL connectivity; disabling it is blocked by a plan-time validation guard.
session_affinity	None	Low	Unleash is stateless; stickiness is unnecessary and adds no value.
enable_iap	only when no SDK traffic	High	IAP blocks all unauthenticated requests, including token-authenticated SDK/CI calls to the Unleash API.
quota_memory_requests / _limits	binary units (4Gi, 8192Mi)	Critical	Bare integers are bytes and block all pod scheduling in the namespace.
Default UI login admin / unleash4all	Change on first login	High	Leaving the default password exposes full admin control of every flag.
enable_pod_disruption_budget	true	Medium	Disabling allows GKE to evict all pods simultaneously during maintenance.
backup_retention_days	7 (raise for prod)	Medium	Too short for compliance retention.

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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. Unleash-specific application configuration shared with the Cloud Run variant is described in Unleash_Common.