Tolgee on GKE Autopilot

Tolgee is an open-source, developer-friendly localization (i18n) and translation management platform built on Spring Boot. This module deploys Tolgee 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 Tolgee 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

Tolgee runs as a Java / Spring Boot web workload. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	Spring Boot pods, 2 vCPU / 4 GiB by default, horizontally autoscaled
Database	Cloud SQL for PostgreSQL 15	Required — Tolgee does not support MySQL or other engines
Object storage	Cloud Storage	A bucket for optional file storage (screenshots/imports)
Secrets	Secret Manager	Auto-generated initial admin password and JWT signing secret; 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.
• Tolgee connects to Cloud SQL over TCP via the Auth Proxy loopback. Its bundled PostgreSQL JDBC driver cannot use a Unix socket, so on GKE the entrypoint connects to the Cloud SQL Auth Proxy sidecar on 127.0.0.1 (plain TCP, no SSL — the proxy terminates TLS). enable_cloudsql_volume therefore defaults to true.
• The JWT secret is generated automatically and stored in Secret Manager. It must never be rotated after first boot without a maintenance window — rotating it immediately invalidates all active user sessions.
• SERVER_PORT, not PORT. Tolgee reads SERVER_PORT = 8080; the module sets it explicitly on the container.
• Session affinity is ClientIP by default so UI sessions from the same client return to the same pod.
• No Redis. Tolgee stores all translation state in PostgreSQL; enable_redis defaults to false.
• Minimum 1 replica is maintained (GKE does not support scale-to-zero); max_instance_count defaults to 5, but keep it at 1 for a stateful single-writer deployment unless you have validated concurrent-writer safety.
• Schema is created by Liquibase on first boot — no separate migration job.

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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 Tolgee workload

Tolgee 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 Tolgee 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 PostgreSQL 15

Tolgee stores all application data (projects, languages, keys, translations, users) in a managed Cloud SQL for PostgreSQL 15 instance. Pods reach it through the Cloud SQL Auth Proxy sidecar on 127.0.0.1 over TCP (Tolgee's JDBC driver cannot use a Unix socket); no public IP is exposed. On first deploy the foundation's create-db-and-user.sh step creates the database and role, and Tolgee runs its own Liquibase migrations on boot.

• 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> --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. Cloud Storage

A Cloud Storage bucket (name_suffix = "storage") is provisioned for optional file storage — Tolgee keeps translations in PostgreSQL, so this bucket holds only uploaded screenshots or import artifacts if you mount it via gcs_volumes or configure Tolgee's S3-compatible file storage. The workload service account is granted access.

• Console: Cloud Storage → Buckets.
• CLI:

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

See App_GKE for CMEK options and GCS Fuse mounts.

D. Secret Manager

Two secrets are generated automatically and stored in Secret Manager: the initial admin password (TOLGEE_AUTHENTICATION_INITIAL_PASSWORD) used to log in for the first time, and the JWT signing secret (TOLGEE_AUTHENTICATION_JWT_SECRET) used to sign all user session tokens. The database password is managed separately by the foundation. On GKE the Common layer also exposes the raw secret values so the workload can bypass Secret Manager read-after-write consistency (the Keycloak/Directus pattern).

• Console: Security → Secret Manager.
• CLI:

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

See App_GKE for the Secret Store CSI integration and rotation.

E. Networking & ingress

By default the workload is exposed through an external Cloud Load Balancing IP (service_type = LoadBalancer). 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.

F. Cloud Logging & Monitoring

Pod stdout/stderr flow to Cloud Logging; GKE and Cloud SQL metrics flow to Cloud Monitoring. Optional uptime checks (against /actuator/health) 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. Tolgee Application Behaviour

• First-deploy database setup. No dedicated init job runs — the App_GKE foundation's create-db-and-user.sh step creates the PostgreSQL role and database and grants schema ownership. Tolgee then creates and migrates its entire schema with Liquibase automatically on first boot.
• Migrations on start. Tolgee applies its Liquibase changesets on every startup, so upgrading the application_version applies schema changes without a separate step.
• The JWT secret is immutable after first boot. It is generated once and written to Secret Manager and kept stable across restarts and replicas. Rotating TOLGEE_AUTHENTICATION_JWT_SECRET immediately invalidates all active user sessions — only rotate during a planned maintenance window.
• First-run login. After deploy, sign in as the initial owner: TOLGEE_AUTHENTICATION_INITIAL_USERNAME (default admin@techequity.cloud) with the generated password from Secret Manager. Change the password and configure additional auth providers (Google/OAuth2/SSO) from the Tolgee UI before going live.
• Health path. The readiness/startup/liveness probes target /actuator/health, which returns an unauthenticated 200 only after Liquibase migrations complete. Allow several minutes on first boot (60-second initial delay plus a wide failure window) — Spring Boot + first-run migrations start more slowly than a typical Node app.
• Single-writer by design. Tolgee has no queue/coordination layer; scaling beyond one pod runs concurrent writers against the same database and NFS attachment volume. Keep a single replica unless you have validated concurrent-writer safety for your workload.
• Inspect the DB wiring injected into the running pod:

  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- env | grep -E 'SPRING_DATASOURCE|SERVER_PORT'

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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 Tolgee are listed; every other input is inherited from App_GKE with its standard behaviour and defaults.

Group 3 — Application Identity

Variable	Default	Description
application_name	tolgee	Base name for resources. Do not change after first deploy.
application_version	latest	Tolgee image tag used as FROM tolgee/tolgee:<tag> for the thin custom wrapper build. Pin to a release (e.g. v3.130.4) in production.

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
container_resources	cpu_limit=2000m, memory_limit=4Gi	Tolgee requires at least 2 GiB memory for reliable operation.
min_instance_count	1	Minimum replicas; GKE requires ≥ 1 (no scale-to-zero).
max_instance_count	5	Maximum replicas. Keep at 1 unless concurrent-writer safety is validated.
container_port	8080	Tolgee's Spring Boot SERVER_PORT.
enable_cloudsql_volume	true	Cloud SQL Auth Proxy sidecar — required; Tolgee connects to the proxy on 127.0.0.1 over TCP.

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	LoadBalancer	How the Kubernetes Service is exposed.
session_affinity	ClientIP	Sticky routing so UI sessions return to the same pod.

Group 7 — StatefulSet

Variable	Default	Description
stateful_pvc_enabled	null (Deployment)	Tolgee stores all state in PostgreSQL/NFS, so a StatefulSet with per-pod PVCs is not needed.

Group 13 — Filesystem (NFS)

Variable	Default	Description
enable_nfs	true	Provisions Cloud Filestore NFS for optional Tolgee attachment storage.
gcs_volumes	[]	GCS Fuse volume mounts for the optional file-storage bucket.

Group 15 — Redis Cache & Queue

Variable	Default	Description
enable_redis	false	Leave off — Tolgee stores all state in PostgreSQL and does not require Redis.

Group 16 — Database Backend

Variable	Default	Description
application_database_name	tolgee	PostgreSQL database name. Immutable after first deploy.
application_database_user	tolgee	Application database user. Immutable after first deploy.

All other inputs follow standard App_GKE behaviour.

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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 stage-specific services.
service_external_ip	External LoadBalancer IP (when a static IP is reserved).
service_url	URL to reach Tolgee.
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 / cicd_configuration	CI/CD status and details (repo, trigger, registry).
github_repository_url / github_repository_owner / github_repository_name	CI/CD GitHub 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.

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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 — an out-of-range redis_port/backup_retention_days, IAP with no authorized identities, a gen1 runtime with NFS/GCS mounts, a database_type that does not match an enabled extension, ResourceQuota memory without a binary unit suffix. 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
TOLGEE_AUTHENTICATION_JWT_SECRET (auto-generated)	Only rotate in a maintenance window	Critical	Rotating it invalidates all active user sessions, forcing immediate re-login for everyone.
application_database_name / application_database_user	Set once	Critical	Immutable after first deploy; renaming recreates the DB/user and destroys all data.
enable_cloudsql_volume	true	Critical	The Auth Proxy sidecar is required for Tolgee's TCP JDBC connection; disabling it removes the 127.0.0.1 endpoint and breaks the database connection.
container_resources.memory_limit	4Gi (≥ 2 GiB)	High	Below ~2 GiB the Spring Boot JVM OOMs during first-boot Liquibase migrations.
max_instance_count	1 unless validated	High	Tolgee has no coordination layer; multiple concurrent writers against one DB/NFS volume can conflict.
session_affinity	ClientIP	High	Without stickiness, UI sessions bounce between pods and users are logged out unexpectedly.
min_instance_count	1	High	GKE requires min ≥ 1; the validation guard rejects 0.
quota_memory_requests / _limits	binary units (4Gi, 8192Mi)	Critical	Bare integers are bytes and block all pod scheduling in the namespace.
application_version	Pin in production	High	latest can pull a new major with incompatible migrations on redeploy.
startup_probe (/actuator/health)	Keep the wide first-boot window	Medium	Too tight a window fails the pod while Liquibase migrations are still running on a fresh DB.
enable_redis	false	Medium	Redis is unused; enabling it adds cost without benefit.

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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. Tolgee-specific application configuration shared with the Cloud Run variant is described in Tolgee_Common.