Kimai on GKE Autopilot

Kimai is a free, open-source time-tracking application (Symfony/PHP) used by freelancers and agencies for billable-hours tracking, timesheets, and reporting that feeds into invoicing. This module deploys Kimai 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 Kimai 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

Kimai runs as a Symfony/PHP pod (the official kimai/kimai2:apache image, wrapped in a thin custom build) on GKE Autopilot. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	Symfony/PHP pod, 1 vCPU / 2 GiB by default; single replica by default (GKE has no scale-to-zero)
Database	Cloud SQL for MySQL 8.0	Required — Kimai_Common fixes the engine; PostgreSQL is not supported
Object storage	Cloud Storage	A storage bucket, GCS-FUSE-mounted at /opt/kimai/var/data for uploaded invoice logos/templates and plugin data
Secrets	Secret Manager	Auto-generated APP_SECRET (Symfony signing key) and ADMINPASS (admin password); database password
Ingress	Cloud Load Balancing	External LoadBalancer; custom domain and reserved static IP are supported (see §4 for the defaults this module's own live deployment actually used)

Sensible defaults worth knowing up front:

• MySQL 8.0 is mandatory. The database engine is fixed by Kimai_Common; selecting any other engine breaks the deployment.
• Custom wrapper image is required, not optional. container_image_source = "custom" builds a thin image FROM kimai/kimai2 whose entrypoint composes Kimai's single DATABASE_URL connection string at container startup from Foundation-injected secret values (see §3).
• container_port = 8001, not port 80 — confirmed via local docker run testing and live deployment. This is the :apache image variant's actual listening port.
• enable_cloudsql_volume = true — this is the opposite default from Kimai_CloudRun. A Cloud SQL Auth Proxy sidecar is injected into the pod and listens on 127.0.0.1; the wrapper entrypoint's DB_IP alias resolves to that loopback address here, rather than the raw private IP Cloud Run uses.
• Two Secret Manager secrets, generated once. APP_SECRET (Symfony CSRF/session signing key) and ADMINPASS (initial super-admin password) — both re-injected from Secret Manager on every container start, so no persistent volume is needed just to keep them stable.
• No scale-to-zero. min_instance_count = 1, max_instance_count = 1 by default; GKE Autopilot keeps a Deployment's replica count at or above its configured minimum.
• enable_nfs defaults true but is functionally unused. It mounts Cloud Filestore NFS at /var/lib/kimai, but the real persistent storage path is the GCS-FUSE-mounted storage bucket at /opt/kimai/var/data. Nothing writes to the NFS mount. Safe to disable.
• No separate migrate job. kimai:install (schema creation and migrations) runs on every container boot, idempotently, as part of the vendor's own entrypoint chain — only a single db-init job is needed to create the database and user beforehand.

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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 Kimai workload

Kimai runs as a single-replica Deployment by default. Autopilot bills for the CPU/memory the pod actually requests. A Cloud SQL Auth Proxy sidecar runs alongside the main container (enable_cloudsql_volume = true).

• Console: Kubernetes Engine → Workloads → select the Kimai workload for pods, events, and logs. Kubernetes Engine → Services & Ingress shows the external IP.
• CLI:

  kubectl get pods,svc -n "$NAMESPACE"
  kubectl logs -n "$NAMESPACE" deploy/<service-name> --tail=100 -c <service-name>

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

B. Cloud SQL for MySQL 8.0

Kimai stores all application data (projects, activities, timesheets, users, invoices) in a managed Cloud SQL for MySQL 8.0 instance. The pod reaches it privately through a Cloud SQL Auth Proxy sidecar listening on 127.0.0.1. On first deploy, a db-init job creates the application database and user; kimai:install then creates the schema on the container's own first 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"
  gcloud sql connect <instance-name> --user=<db-user> --database=<db-name> --project "$PROJECT"

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

C. Cloud Storage

Two GCS buckets can exist for this deployment: a storage bucket provisioned by Kimai_Common and GCS-FUSE-mounted at /opt/kimai/var/data (uploaded invoice logos/templates, plugin data), and a separate, generic Foundation-level bucket (storage_buckets, defaulting to a bucket named data) that Kimai does not read or write unless you wire it up explicitly.

• Console: Cloud Storage → Buckets.
• CLI:

  gcloud storage buckets list --project "$PROJECT"

See App_GKE for CMEK options and GCS Fuse CSI mounts.

D. Secret Manager

Two secrets are generated automatically and stored in Secret Manager: APP_SECRET (Symfony CSRF/session signing key) and ADMINPASS (the initial super-admin account password). The database password is managed separately by the foundation.

• Console: Security → Secret Manager.
• CLI:

  gcloud secrets list --project "$PROJECT" --filter="name~kimai"
  gcloud secrets versions access latest --secret=<secret-name> --project "$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; a Kubernetes Ingress for custom domains and a reserved static IP can be layered on (both module defaults are true, though this module's own live deployment was run with both set false — see Outputs and §4).

• 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, with optional uptime checks and alert policies.

• 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. Kimai Application Behaviour

• A single DATABASE_URL composed entirely at runtime, not passed through Terraform. Kimai's Doctrine DBAL layer reads one connection string, DATABASE_URL=mysql://user:pass@host:port/db?charset=utf8mb4&serverVersion=8.0, not discrete DB_* variables. Kimai_Common builds a thin custom wrapper image FROM kimai/kimai2 whose entrypoint.sh composes DATABASE_URL at container start from the Foundation-injected DB_USER/DB_NAME/DB_PASSWORD/DB_IP env vars — URL-encoding the password with php -r 'echo rawurlencode(...)' — before handing off unmodified to the vendor's own docker-php-entrypoint /entrypoint.sh.
• DB_IP resolves to the Auth Proxy sidecar's loopback on GKE. The wrapper reads the host from $DB_IP (aliased via db_host_env_var_name = "DB_IP"). On GKE, with enable_cloudsql_volume = true (the default), this resolves to the cloud-sql-proxy sidecar's 127.0.0.1 address — a plain host with no colons, just like the raw private IP Cloud Run's variant of this same module uses. This is why the same wrapper entrypoint code works unmodified on both platforms.
• Verified locally before ever touching the cloud. The password URL-encoding step and the vendor's own DB-wait preflight check were both confirmed by building the wrapper image and running it locally against a real MySQL container with a password containing special characters (@:/?), catching and fixing issues before the first cloud deploy attempt.
• Health check behaviour. Both the startup and liveness probes target GET /en/login (Kimai's login page), which returns 200 once the application is ready.

  EXTERNAL_IP=$(kubectl get svc -n "$NAMESPACE" -o jsonpath='{.items[0].status.loadBalancer.ingress[0].ip}')
  curl -s -o /dev/null -w "%{http_code}\n" "http://${EXTERNAL_IP}/en/login"   # expect 200

• Admin bootstrap runs on every boot, idempotently. The vendor's own entrypoint runs kimai:user:create admin "$ADMINMAIL" ROLE_SUPER_ADMIN "$ADMINPASS" on every container start whenever ADMINPASS is set — a no-op once the account exists. The username is always admin, hardcoded by the vendor image regardless of admin_email's value.
• Inspect job execution:

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

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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 Kimai are listed; every other input is inherited from App_GKE with its standard behaviour.

Group 1 — Project & Identity

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

Group 3 — Application Identity

Variable	Default	Description
application_name	kimai	Base name for resources. Do not change after first deploy.
application_display_name	Kimai	Human-readable name shown in the Console.
application_description	Kimai time tracking on GKE	Kubernetes workload description.
application_version	latest	Image tag driving the kimai/kimai2 build. "latest" maps to the maintained :apache rolling tag; any other value maps to "<version>-apache".
admin_email	admin@example.com	Super-admin account email, injected as ADMINMAIL. The account username is always admin, hardcoded by the vendor entrypoint.
enable_gcs_storage_volume	true	GCS-FUSE-mount the storage bucket at /opt/kimai/var/data.

Group 4 — Runtime & Scaling

Variable	Default	Description
container_image_source	custom	Builds the DATABASE_URL-composing wrapper image via Cloud Build — required, not optional, for this module.
min_instance_count / max_instance_count	1 / 1	GKE has no scale-to-zero; single replica by default.
container_port	8001	Kimai's :apache image variant listens on 8001, confirmed via local testing and live deployment.
cpu_limit / memory_limit	1000m / 2Gi	Per-pod resource limits.
php_memory_limit	512M	PHP memory_limit (the vendor entrypoint reads the lowercase memory_limit env var directly).
enable_cloudsql_volume	true	Cloud SQL Auth Proxy sidecar on 127.0.0.1. Keep true on GKE — the wrapper's DB_IP alias depends on it.

Group 6 — GKE Backend & Cluster

Variable	Default	Description
service_type	LoadBalancer	External IP by default.
session_affinity	ClientIP	Routes a client's requests to the same pod.
workload_type	null	Auto-resolves to Deployment (Kimai needs no per-pod PVC identity).

Group 11 — Jobs & Scheduled Tasks

Variable	Default	Description
initialization_jobs	[]	Leave empty to use the built-in single db-init job. There is no separate migrate job — kimai:install runs on every container boot, idempotently.

Group 13 — Filesystem (NFS)

Variable	Default	Description
enable_nfs	true	Functionally unused — mounted at /var/lib/kimai, but Kimai's real persistent storage is the GCS-FUSE-mounted storage bucket at /opt/kimai/var/data. Safe to disable.

Group 14 — Cloud Storage & Artifact Registry

Variable	Default	Description
storage_buckets	[{ name_suffix = "data" }]	Generic Foundation-level bucket. Not read or written by Kimai.
gcs_volumes	[]	Additional GCS Fuse volume mounts, merged with the storage bucket mount.

Group 16 — Database Backend

Variable	Default	Description
database_type	null (resolves to MYSQL_8_0)	Fixed by Kimai_Common.
application_database_name / application_database_user	kimai	Tenant-prefixed at deploy time. Immutable after first deploy.
db_host_env_var_name	DB_IP	Aliases the DB host so the wrapper's DATABASE_URL composition reads a plain, colon-free host — resolves to the Auth Proxy sidecar's loopback on GKE.
db_user_env_var_name / db_name_env_var_name / db_port_env_var_name / db_password_env_var_name	"" (all four)	Unused by Kimai — the wrapper reads the standard DB_USER/DB_NAME/DB_PASSWORD directly and hardcodes port 3306.

Group 19 — Custom Domain, Static IP & Networking

Variable	Default	Description
enable_custom_domain	true	Kubernetes Ingress with application_domains. This module's own live-verified deployment set this false (see config/deploy.tfvars).
reserve_static_ip	true	A stable IP that survives redeploys. This module's own live-verified deployment set this false too.
network_tags	["nfsserver"]	Firewall targeting; required for NFS connectivity when enable_nfs = true.

Group 15 — Redis

Variable	Default	Description
enable_redis	false	Kimai has no built-in Redis integration used by this module — its default cache backend is the local filesystem.

Every other input (Group 0 metadata, Group 2 environment, Group 5 secrets, Group 7 StatefulSet, Group 8 resource quota, Group 9 reliability, Group 10 observability, Group 12 CI/CD, Group 17 backup, Group 18 custom SQL, Group 20 IAP, Group 21 Cloud Armor, Group 22 VPC-SC) behaves exactly as documented in App_GKE.

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5. Outputs

Returned on a successful deployment — the quickest way to locate and explore the running resources.

Output	Description
service_name	Kubernetes Service name.
namespace	Kubernetes namespace.
service_cluster_ip / service_external_ip	Internal / external IP.
service_url	Service URL.
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.
database_host	127.0.0.1 via the Cloud SQL Auth Proxy sidecar.
storage_buckets	Created Cloud Storage buckets.
container_image / container_registry	Deployed image and Artifact Registry repo.
initialization_jobs	Name of the setup job (db-init).
kubernetes_ready	Whether the cluster endpoint is available and all K8s resources are deployed.
deployment_id / tenant_id / resource_prefix	Naming identifiers.
project_id / project_number	Project identifiers.
vpc_sc_enabled / vpc_sc_perimeter_name / vpc_sc_dry_run_mode	VPC-SC 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. Invalid configuration fails the plan with a clear, named error before any resource is created.

Setting	Sensible value	Risk	Consequence if wrong
container_image_source	custom	Critical	Switching to prebuilt deploys the stock kimai/kimai2 image with no wrapper entrypoint — DATABASE_URL is never composed, so the pod cannot reach MySQL at all.
enable_cloudsql_volume	true on GKE	Critical	Setting false removes the Auth Proxy sidecar the wrapper entrypoint's DB_IP alias depends on to reach Cloud SQL — the pod cannot connect.
container_port	8001	Critical	The :apache image variant listens on 8001, not 80 — pointing the platform at the wrong port makes the service unreachable even though the container is healthy.
application_database_name / application_database_user	Set once	Critical	Immutable after first deploy; renaming recreates the DB/user and destroys all timesheets, projects, and invoices.
APP_SECRET (auto-generated)	Never hand-edit in Secret Manager after first boot	High	Kimai uses this as a Symfony security-signing key; changing it invalidates CSRF tokens and active sessions.
Default administrator account (username always admin, password in the ADMINPASS secret)	Retrieve the generated password from Secret Manager and log in promptly	High	The admin password is a real, per-deployment generated secret, not a public well-known default — but still worth confirming who has read access to the secret.
max_instance_count	1 unless verified otherwise	High	Scaling beyond 1 pod without verifying Kimai's session behaviour under multiple pods risks inconsistent user sessions across pods.
enable_nfs	false unless needed for another purpose	Low / cost	Defaults true and provisions a Filestore share Kimai never uses — a needless recurring cost; real persistence is the GCS-FUSE-mounted storage bucket.
enable_cloud_armor	enable for production	Medium	The service is publicly reachable without WAF protection by default.

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