Speedtest Tracker on GKE Autopilot

Speedtest Tracker is a free, open-source, self-hosted internet speed test monitoring tool built on Laravel (PHP). It runs Ookla speed tests on a recurring schedule, stores results in a database, and presents them as historical charts through a web dashboard and REST API. This module deploys Speedtest Tracker 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 Speedtest Tracker 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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What Speedtest Tracker costs on RAD, and how that compares

Running Speedtest Tracker in your own GCP project costs about $93.10/month in Google Cloud charges; RAD's module fee is a one-time 75 credits (or 67.5 credits in a RAD-managed project), covering setup and support -- not the ongoing cloud bill, which Google bills you directly in your own project or RAD meters hourly in credits in a RAD-managed one. Or see the Cloud Run guide for the alternative deployment target; either way, if you deploy into a RAD-managed project you can pause the whole thing for free when you are not using it -- see Pause it for free below.

What you pay on RAD

	Your own project	RAD-managed project
Module fee	75 credits, once	67.5 credits, once (10% lower)
Build time	metered in credits as the build runs (a few credits, typically)	same
Google Cloud running cost	~$93.10/month, billed to your own billing account at Google's list price	~87 credits/day, metered hourly by RAD at list price plus margin

Default running cost in your own project

Resource	US$/month (Google list price, us-central1)
GKE Autopilot pod, 1x vCPU / 1 GiB	$36.08
Cloud SQL for MySQL, 1 vCPU / 3.75 GB, zonal, 10 GB SSD	$51.02
Cloud NAT and networking	$5.00
Cloud Storage (add-ons, backups)	$1.00
GKE cluster management fee	shared across every GKE app in the project; $0 if this is your only cluster, else ~$73
Total	$93.10

How it compares

• Speedtest Tracker's own footprint here (1x vCPU / 1 GiB) is smaller than this reference class, so an even cheaper VPS tier would do just as well, but sized to the smallest commonly-quoted class for comparison: Hetzner CPX22 (2 vCPU/4GB) runs about $24/month, a DigitalOcean 2 vCPU/4GB Droplet is also $24/month, and a GCP Compute Engine e2-standard-2 (2 vCPU/8GB) is about $49/month -- plus the admin's own time for backups, security patches and upgrades, which RAD's managed Cloud SQL, Secret Manager and monitoring cover for you -- but RAD's price is never meant to beat a VPS, only to replace the admin time a VPS still needs.
• Speedtest Tracker runs scheduled tests on a timer rather than serving continuous traffic, so note this module needs alwaysOn compute to keep the schedule firing on Cloud Run, which is why it is the costlier of the two targets here despite the light workload.

Pause it for free: delete a RAD-managed project, restore it when you need it

This is the headline for a RAD-managed project. Deleting a RAD-managed project first unlinks its billing, then asks Google to delete the project outright -- Google's own 30-day recoverable soft delete. Unlike deleting one module, this does not tear down Cloud SQL, any VM or the compute resource one by one: the whole project simply stops, and nothing is charged while it waits, because billing is already unlinked.

Restoring, within 30 days and only by the project's owner, asks Google to undelete the project and reattaches its billing account, then asks you to run Update on each deployment to confirm everything came back. Because nothing was individually destroyed, that Update finds the same resources already there -- it is a check, not a rebuild, and an Update never charges the module fee again. This costs only a handful of credits (under US$1) in total for a typical 2-3-deployment chain.

What this needs: you must own the project (not one RAD only manages billing for), you must restore it yourself within 30 days -- after that Google deletes it for good -- and restoring is admitted like creating a new project, so your purchased credit balance must still clear the tier's floor (100 credits for the sandbox tier most study/demo use fits). Google says most services are fully working again within 36 hours of a restore.

One real gap: nightly backups are written to a bucket inside the project, and that bucket has Cloud Storage's soft-delete explicitly turned off, so it is very likely gone as soon as you delete the project -- even though the project itself is recoverable for 30 days. If you have customised the app and want to keep that work, copy a backup out (to Google Drive, or a bucket outside the project) before deleting. For a default install with nothing irreplaceable in it, this does not matter.

Pay only while you use it, the other way: delete and redeploy

In your own project (or once you are past the 30-day restore window above), the alternative is to delete Speedtest Tracker outright and redeploy it later. A redeploy costs the module fee again, plus the builds -- roughly 75 + 3-6 credits of build time.

Deleting saves money only once Speedtest Tracker would otherwise sit unused long enough to clear that redeploy cost against its own daily running cost -- against the own-project total above, that works out to about 3 days or more. Most of the running cost here is usually the database; it stops only when nothing else in the project uses it, so deleting this app while something else shares the project saves only this app's own compute part.

Keep data first: nightly backups go to a bucket inside the deployment and are deleted with it, so copy the latest backup out before deleting if you want to keep it.

Lab sessions and Managed Environments

• Lab sessions, for training: a trainer runs a session for a class. Each participant gets the app in their own Google Cloud project for 15 minutes to 24 hours, within an allowance the trainer sets. Either the trainer funds every place, or each participant pays for their own. Everything is deleted when the session ends and unused credits go back to the trainer.
• Managed Environments, for consultancies: a partner runs the app for a client from a ring-fenced wallet it funds, and settles with the client directly. If the wallet runs low, billing pauses and the data is kept, so nobody receives an unexpected charge. At the end the partner hands the project over and the deployments become the client's own.
• Credits can be bought in more than 20 currencies, including XAF, XOF, NGN, GHS, KES and ZAR, by card, bank transfer or mobile money.

Sources (8 October 2026): Google Cloud Billing Catalog API list prices; radmodules.dev/pricing for RAD's own fees and daily-credit estimates; https://cloud.google.com/resource-manager/docs/delete-restore-projects for the pause/restore mechanics.

1. Overview

Speedtest Tracker runs as a PHP web workload on GKE Autopilot. The deployment wires together a focused set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	GKE Autopilot	PHP (LinuxServer) pod, 1 vCPU / 1 GiB by default, single replica
Database	Cloud SQL for MySQL 8.0	Required — this module fixes MySQL; the upstream image's SQLite default is bypassed
Cache & sessions	Redis (optional)	Disabled by default; Speedtest Tracker uses the local file/sync cache driver
Secrets	Secret Manager	Auto-generated Laravel APP_KEY; database password
Ingress	Cloud Load Balancing	External LoadBalancer, custom domain + managed certificate + static IP by default

Sensible defaults worth knowing up front:

• MySQL 8.0 is mandatory. The database engine is fixed by the shared application layer (database_type resolves to MYSQL_8_0); PostgreSQL is not supported.
• The prebuilt linuxserver/speedtest-tracker image is used directly. There is no custom Cloud Build; the official LinuxServer.io image is mirrored into Artifact Registry (enable_image_mirroring = true) and deployed as-is. Fallback: ghcr.io/alexjustesen/speedtest-tracker (Alpine-based) if a specific runtime is ever found incompatible with the LinuxServer s6-overlay image.
• The container listens on port 80 (container_port = 80, container_protocol = "http1").
• A single replica is maintained (min_instance_count = 1, max_instance_count = 1; GKE has no scale-to-zero). This is load-bearing, not just a cost default — the SPEEDTEST_SCHEDULE Laravel scheduler has no cross-pod locking, so more than one replica risks firing duplicate scheduled speed tests.
• APP_KEY is immutable after first boot. The Laravel app key is generated once and stored in Secret Manager; rotating it makes all encrypted DB values undecryptable.
• The image runs php artisan migrate --force automatically on start, so the schema is created on first boot after db-init provisions the database and user — there is no separate migration job.
• No storage by default. Speedtest Tracker stores all results and configuration in Cloud SQL — create_cloud_storage and enable_nfs default off.
• GKE connects to Cloud SQL through the Auth Proxy sidecar on 127.0.0.1:3306 (enable_cloudsql_volume = true), and the GKE wiring overrides DB_HOST = "127.0.0.1".
• A custom domain, managed certificate, and reserved static IP are enabled by default (enable_custom_domain = true, reserve_static_ip = true), with session_affinity = "ClientIP".

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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 Speedtest Tracker workload

Speedtest Tracker's pod is scheduled on Autopilot, which bills for the CPU/memory the pod actually requests. The workload runs as a single-replica Deployment so the in-process cron scheduler never runs concurrently across pods.

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

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

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

B. Cloud SQL for MySQL 8.0

Speedtest Tracker stores all speed test results and application configuration in a managed Cloud SQL for MySQL 8.0 instance. Pods reach it privately through the Cloud SQL Auth Proxy sidecar on 127.0.0.1:3306 (enable_cloudsql_volume = true); no public IP is exposed. On first deploy an initialization 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=speedtesttracker --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. Redis (optional cache & sessions)

Redis is disabled by default (enable_redis = false); Speedtest Tracker uses its local file/sync cache and session drivers, which is fine for a single-replica deployment. When enable_redis = true is set, the shared layer injects REDIS_HOST and REDIS_PORT.

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

  redis-cli -h <redis-host> ping
  # Confirm the DB/schedule wiring injected into the running pod:
  kubectl exec -n "$NAMESPACE" deploy/<service-name> -- env | grep -E 'DB_|REDIS_|SPEEDTEST_'

D. Secret Manager

One cryptographic secret is generated automatically and stored in Secret Manager: the Laravel APP_KEY (base64:<44-char base64>), used to encrypt all application data that Speedtest Tracker stores encrypted. The database password is managed separately by the foundation.

• Console: Security → Secret Manager.
• CLI:

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

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

E. Networking & ingress

By default the workload is exposed through an external Cloud Load Balancing IP with a custom domain and Google-managed certificate (enable_custom_domain = true), and a static IP is reserved (reserve_static_ip = true) 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 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. Speedtest Tracker Application Behaviour

• First-deploy database setup. An initialization Job runs db-init.sh using mysql:8.0-debian. It detects the Cloud SQL socket or TCP endpoint, waits for MySQL to be reachable, creates the application database and user, grants privileges, verifies the app user can connect, and gracefully shuts down the Cloud SQL Auth Proxy sidecar. The job is idempotent and safe to re-run (max_retries = 3).
• Schema auto-migration on start. The LinuxServer Speedtest Tracker image runs php artisan migrate --force automatically on every container start, so the schema is created on first boot and upgraded on later boots — there is no separate migration job.
• APP_KEY is immutable after first boot. The Laravel app key is generated once and written to Secret Manager. Rotating it makes all encrypted DB values permanently undecryptable. Only rotate during a planned maintenance window with a re-encryption plan.
• In-process cron scheduler. SPEEDTEST_SCHEDULE (default "0 * * * *", hourly) drives Speedtest Tracker's own Laravel scheduler to run automated speed tests. Unlike Cloud Run, GKE pods run continuously (no scale-to-zero concern), so this fires reliably as long as the single pod is running.
• Result pruning. PRUNE_RESULTS_OLDER_THAN (default "0", disabled) automatically deletes speed test results older than the configured number of days.
• Health path. The liveness probe targets /api/healthcheck by default — Speedtest Tracker's unauthenticated JSON health endpoint. The startup probe is a TCP check. Allow a generous first-boot window (30-second initial delay, high failure threshold) for the automatic migrations.
• First-run setup. Speedtest Tracker's web UI walks through account creation on first visit — there is no seeded default admin account to change.
• Inspect job execution:

  kubectl get jobs -n "$NAMESPACE"
  kubectl logs -n "$NAMESPACE" job/<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 Speedtest Tracker 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_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	speedtesttracker	Base name for resources. Do not change after first deploy.
application_display_name	Speedtest Tracker	Human-readable name shown in the Console.
application_description	Speedtest Tracker — automated internet speed test monitoring and history on GKE Autopilot	Workload description.
application_version	latest	linuxserver/speedtest-tracker image tag; pin (e.g. version-v1.6.3) in production.
speedtest_schedule	0 * * * *	Cron expression for the automated speed test schedule.
prune_results_older_than	0	Days after which old results are pruned; 0 disables pruning.

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
container_image_source	prebuilt	Deploy the mirrored LinuxServer image directly — no custom build.
container_image	""	Override image reference; leave empty to use the mirrored default.
enable_image_mirroring	true	Mirror the LinuxServer image into Artifact Registry before deployment.
min_instance_count	1	Minimum replicas; keep at 1.
max_instance_count	1	Maximum replicas. Do not raise while speedtest_schedule is set — risks duplicate scheduled speed tests.
container_port	80	Speedtest Tracker listens on port 80.
container_protocol	http1	HTTP/1.1.
cpu_limit	1000m	CPU per pod; 1 vCPU by default.
memory_limit	1Gi	Memory per pod.
timeout_seconds	300	Maximum request duration (0–3600 seconds).
enable_cloudsql_volume	true	Cloud SQL Auth Proxy sidecar (127.0.0.1:3306); required on GKE.

Group 5 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra non-secret settings (e.g. DISPLAY_TIMEZONE, SPEEDTEST_SERVERS). Do not set APP_KEY or DB_* 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.
workload_type	null	Resolves to Deployment (default).
session_affinity	ClientIP	Sticky routing keeps a client's UI session on one pod.
enable_network_segmentation	false	Create Kubernetes NetworkPolicy resources.
termination_grace_period_seconds	30	Seconds to wait after SIGTERM before SIGKILL.

Group 7 — StatefulSet

Variable	Default	Description
stateful_pvc_enabled	null	Not needed — Speedtest Tracker has no per-pod block storage requirement.
stateful_pvc_size	10Gi	Per-pod PVC storage size (if enabled).
stateful_pvc_mount_path	/data	Container mount path for the PVC.
stateful_pvc_storage_class	standard-rwo	Kubernetes StorageClass for PVCs.

Group 8 — Resource Quota

Variable	Default	Description
enable_resource_quota	false	Enforce a namespace ResourceQuota.
quota_cpu_requests / quota_cpu_limits	""	CPU quota.
quota_memory_requests / quota_memory_limits	""	Memory quota — use binary units (4Gi, 8192Mi).
quota_max_pods / quota_max_services / quota_max_pvcs	""	Object-count quotas.

Group 9 — Reliability

Variable	Default	Description
enable_pod_disruption_budget	false	Protect availability during node upgrades.
pdb_min_available	1	Minimum pods available during voluntary disruptions.
enable_topology_spread / topology_spread_strict	false	Spread pods across zones.

Group 10 — Observability & Health

Variable	Default	Description
startup_probe	TCP, path /api/healthcheck, 30s	Startup probe (port-listening check).
liveness_probe	HTTP /api/healthcheck, 300s delay	Liveness probe against Speedtest Tracker's unauthenticated health endpoint.
startup_probe_config / health_check_config	App_GKE-level probes	Infrastructure-level probes.
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.
cron_jobs	[]	For unrelated maintenance tasks — Speedtest Tracker's own speed-test schedule runs in-process via SPEEDTEST_SCHEDULE.
additional_services	[]	Sidecar or helper services deployed alongside Speedtest Tracker.

Group 12 — CI/CD & Binary Authorization

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	Not required by default — all state lives in Cloud SQL.
nfs_mount_path	/config	Mount path if NFS is enabled (e.g. for custom certs).
nfs_volume_name	nfs-data-volume	Kubernetes volume name for the NFS mount.
nfs_instance_name / nfs_instance_base_name	"" / app-nfs	NFS server discovery/naming.

Group 14 — Cloud Storage & Artifact Registry

Variable	Default	Description
create_cloud_storage	true	Create any buckets declared in storage_buckets (empty by default).
storage_buckets	[]	GCS buckets to provision. Not needed by default.
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	7	Maximum recent Artifact Registry images to keep.
delete_untagged_images	true	Automatically delete untagged images.
image_retention_days	30	Days after which images are eligible for deletion.

Group 15 — Redis Cache & Sessions

Variable	Default	Description
enable_redis	false	Inject REDIS_HOST/REDIS_PORT so Speedtest Tracker can use Redis for cache/sessions. Not required by default.
redis_host	""	Redis endpoint. Leave empty to use the NFS server IP (requires enable_nfs = true).
redis_port	6379	Redis port.
redis_auth	""	Optional Redis auth password (sensitive).

Group 16 — Database Backend

Variable	Default	Description
database_type	null → MYSQL_8_0	Fixed — Speedtest Tracker requires MySQL 8.0 in this module.
application_database_name	speedtesttracker	MySQL database name (tenant-prefixed). Immutable after first deploy.
application_database_user	speedtesttracker	Application database user (tenant-prefixed). Immutable after first deploy.
database_password_length	32	Generated password length.
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 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.

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.
network_tags	["nfsserver"]	Node/pod network tags (relevant only if enable_nfs = true).

Group 20 — Identity-Aware Proxy (IAP)

Variable	Default	Description
enable_iap	false	Require Google sign-in in front of Speedtest Tracker.
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 (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 stage-specific services.
service_external_ip	External LoadBalancer IP (when a static IP is reserved).
service_url	URL to reach Speedtest Tracker.
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 (empty by default).
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 — 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 the engine Speedtest Tracker requires, an out-of-range redis_port/backup_retention_days. This module additionally validates that max_instance_count <= 1 whenever speedtest_schedule is set. Invalid configuration fails the plan with a clear, named error before any resource is created.

Setting	Sensible value	Risk	Consequence if wrong
APP_KEY (auto-generated)	Never rotate after first boot	Critical	Rotating it makes all encrypted DB values permanently undecryptable.
application_database_name / application_database_user	Set once	Critical	Immutable after first deploy; renaming recreates the DB/user and destroys all data.
enable_backup_import	false unless restoring	Critical	Enabling without a valid backup_uri fails the import job.
database_type	MYSQL_8_0	Critical	Speedtest Tracker requires MySQL in this module; any other engine breaks startup.
quota_memory_requests / _limits	binary units (4Gi, 8192Mi)	Critical	Bare integers are bytes and block all pod scheduling in the namespace.
max_instance_count	1	High	Scaling beyond 1 with an active speedtest_schedule risks duplicate speed tests firing on the same schedule tick — the Laravel scheduler has no cross-pod locking.
memory_limit	1Gi	High	Lower values risk OOM kills during migrations or concurrent dashboard use.
enable_cloudsql_volume	true	High	The Auth Proxy sidecar is required for MySQL connectivity on GKE; disabling it is blocked by a plan-time validation guard.
min_instance_count	1	High	GKE requires min ≥ 1; keeping 1 also keeps the cron scheduler running continuously.
liveness_probe path	/api/healthcheck (default)	Medium	Pointing the probe at any other path never returns healthy — /api/healthcheck is Speedtest Tracker's unauthenticated JSON health endpoint.
enable_iap	only when readers must authenticate	High	IAP blocks all anonymous access.
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. Speedtest Tracker-specific application configuration shared with the Cloud Run variant is described in SpeedtestTracker_Common.

Related guides

• Hands-on lab: Speedtest Tracker on GKE Autopilot — deploy it step by step, with the console screens and commands at each stage.
• Speedtest Tracker on Google Cloud Run — the same application on Cloud Run, for when you need the other deployment target.
• Speedtest Tracker Common — Shared Application Configuration — the configuration shared by both deployment targets.