TechnitiumDNS on Cloud Run — Lab Guide

📖 Configuration Guide

Overview

Estimated time: 45–75 minutes

⚠️ Before you start: this module deploys Technitium's web admin console + REST API only (port 5380/HTTP). Technitium's core DNS resolver function (port 53/udp+tcp) cannot be exposed through Cloud Run's HTTP(S)-only ingress. This lab covers managing DNS zones/records via the console — it does NOT make this deployment usable as an actual DNS resolver from any client.

Technitium DNS Server is an open-source, self-hosted authoritative/recursive DNS server with a full-featured web console for managing zones, records, DNS-based blocking, and forwarders — no external database required. This lab takes you through the full operational lifecycle of the TechnitiumDNS on Cloud Run module on Google Cloud: deploy it, access and verify it, run it day-to-day, observe it, diagnose common problems, and tear it down.

The lab focuses on operating the Cloud Run module and the Google Cloud platform, not on TechnitiumDNS's DNS-server product features. For the complete list of provisioned services and every configuration input (organised by group), see the Configuration Guide — this lab deliberately does not duplicate that detail so it stays accurate over time.

Objectives

By the end of this lab you will be able to:

• Deploy the module from the RAD platform and locate the resources it provisions.
• Access and verify the running console, including a first login and a zone-creation smoke test.
• Perform day-2 operations — inspect, update, and manage secrets.
• Observe the service with Cloud Logging and Cloud Monitoring.
• Diagnose and resolve the most common deployment and runtime issues.
• Tear the deployment down cleanly.

Prerequisites

• Services_GCP (provides the VPC, Artifact Registry, and shared service accounts this module depends on). You do not need to deploy this yourself first — the platform automatically detects whether it already exists in the target project and provisions it before this module if not (see Task 1).
• A Google Cloud project with billing enabled.
• gcloud CLI authenticated: gcloud auth login and gcloud auth application-default login.
• Project Owner (or equivalent) IAM on the project.
• Bringing your own project? Before the first deploy into it, the deployment confirmation dialog asks you to prove you control it (Get verification code, run the commands it shows as a project Owner, then Verify) and to give the RAD deployment service account the Owner role. A project RAD creates for you needs neither.
• Advanced mode for later changes. The create form asks only for the first page of inputs (and, in a project RAD creates for you, little more than the tenant name and region). Every other input in the Configuration Guide — including the scaling and version inputs in the Day-2 tasks — is changed afterwards with Update on the deployment's page after ticking Enable advanced mode, which needs a credit balance that covers the update's estimated build cost (updates never carry a module fee). On a lab environment only an administrator can use Advanced mode.
• RAD platform access with permission to deploy modules into the project.

Set these shell variables once; every task below reuses them:

export PROJECT="<your-gcp-project-id>"
export REGION="us-central1"          # the region you deploy into

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Task 1 — Deploy the module [Automated]

1. In the RAD platform, open Solutions → Solution Catalog → RAD modules, then open TechnitiumDNS (Cloud Run) from the Platform Modules list, choose Configuration Form under How would you like to configure this deployment? (the form opens on the Conversational Assistant if you hold purchased credits or are a partner or administrator), set project_id, and review the inputs. Configure only what you need — the Configuration Guide documents every input by group, with defaults. Click Deploy Module, review the estimated cost in the Deployment Confirmation dialog when it appears and click Submit (if the dialog then adds a confirmation step, such as verifying a project you bring, complete it and click Confirm), which opens the deployment status page with real-time logs.

2. The platform provisions a single Cloud Run v2 service running the official prebuilt technitium/dns-server image, plus one Cloud Storage bucket (mounted at /etc/dns) and one auto-generated admin-password secret. No database is provisioned. Since the image is prebuilt (no Cloud Build step) and there is no database-initialisation job to wait for, a first deploy is typically fast (roughly 3–7 minutes).

3. When it completes, discover the service with a name-agnostic filter (so the command keeps working regardless of the deployment suffix):

   SERVICE=$(gcloud run services list --project="$PROJECT" --region="$REGION" \
     --filter="metadata.name~technitiumdns" --format="value(metadata.name)" --limit=1)
   SERVICE_URL=$(gcloud run services describe "$SERVICE" \
     --project="$PROJECT" --region="$REGION" --format="value(status.url)")
   echo "Service: $SERVICE"
   echo "URL:     $SERVICE_URL"

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Task 2 — Access & verify [Manual]

1. Confirm the service is healthy — the console root page responds as soon as the server binds its port, with no database dependency to wait on:

   curl -s -o /dev/null -w '%{http_code} %{size_download}\n' "$SERVICE_URL/"
   # expect 200 and a large body (the console's rendered HTML, not an empty response)

2. Retrieve the auto-generated admin password:

   SECRET=$(gcloud secrets list --project="$PROJECT" --filter="name~admin-password" \
     --format="value(name)" --limit=1)
   gcloud secrets versions access latest --secret="$SECRET" --project="$PROJECT"

3. Open $SERVICE_URL in a browser and log in as admin with that password. Immediately change the password from the console's own user-management page — Technitium only reads DNS_SERVER_ADMIN_PASSWORD on the very first boot, so rotating the Secret Manager value later has no effect on the live console; the console's own change-password flow is the only way to rotate it going forward.

4. Run a zone-creation smoke test to confirm the persisted /etc/dns volume actually works: in Zones → Add Zone, create a simple primary zone (e.g. example.test), add an A record, save, then redeploy or restart the revision and confirm the zone and record are still present — proving the GCS-mounted config volume genuinely persists state across restarts.

5. Remember: no client anywhere can resolve DNS queries against this deployment. The console lets you fully manage zone data, but only the web console/API is reachable — not port 53.

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Task 3 — Operate & keep it running (Day-2) [Manual]

1. Inspect the service and its revisions (each deploy creates an immutable revision; traffic shifts to the newest healthy one):

   gcloud run services describe "$SERVICE" --project="$PROJECT" --region="$REGION"
   gcloud run revisions list --service="$SERVICE" --project="$PROJECT" --region="$REGION"

2. Update the application version by changing the version input in the RAD platform and applying it via Update; a new revision rolls out pulling the newly-tagged prebuilt image. Pin an explicit version in production rather than relying on latest.

3. Manage secrets:

   gcloud secrets list --project="$PROJECT" --filter="name~technitiumdns"

   Only the auto-generated DNS_SERVER_ADMIN_PASSWORD appears by default; this list is otherwise only populated if you supplied entries via secret_environment_variables.

4. Enable Identity-Aware Proxy for a production deployment — set enable_iap = true with authorized users/groups and apply via Update. Without IAP, the console is protected only by its own admin password over the public internet.

5. There is no database to open a session against — all state lives in the persisted /etc/dns volume, inspectable via gcloud storage ls:

   BUCKET=$(gcloud storage buckets list --project="$PROJECT" --filter="name~-config" \
     --format="value(name)" --limit=1)
   gcloud storage ls "gs://$BUCKET/"

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Task 4 — Observe: Logging & Monitoring [Manual]

1. Logs — from the CLI or the Logs Explorer:

   gcloud run services logs read "$SERVICE" --project="$PROJECT" --region="$REGION" --limit=50

   Logs Explorer filter: resource.type="cloud_run_revision" AND resource.labels.service_name="<service>".

2. Monitoring — open the Cloud Run dashboard for the service and review request count, request latency, instance count, and CPU/memory utilisation. Because cpu_always_allocated = false by default, expect the instance count to fall to zero between admin sessions — this is expected scale-to-zero behaviour, not a misconfiguration. If a Cloud Monitoring uptime check is enabled, confirm it is green under Monitoring → Uptime checks.

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Task 5 — Troubleshoot & debug [Manual]

Durable techniques for the failure modes you are most likely to hit. These are platform-level diagnostics and do not change with TechnitiumDNS releases.

• Revision unhealthy / console won't load: inspect the latest revision and its logs for startup errors. The startup and liveness probes both target /, which should return 200 within seconds of boot — TechnitiumDNS has no database to wait on, so a slow or failing probe usually points at a container or storage-mount issue rather than a downstream dependency.

  gcloud run revisions list --service="$SERVICE" --project="$PROJECT" --region="$REGION"
  gcloud run services logs read "$SERVICE" --project="$PROJECT" --region="$REGION" --limit=100

• "I can't resolve DNS against this deployment": this is expected — see the disclosure at the top of this guide. This module intentionally exposes only the web console/API, never port 53.
• Zones/records disappear after a restart: confirm the config Cloud Storage bucket exists and is mounted (gcloud storage buckets list --filter="name~-config"); a missing/misconfigured GCS volume means /etc/dns reverts to an empty ephemeral filesystem on every restart.
• Can't log in with the Secret Manager password: remember it only applies on the very first boot. If the console was ever started before (even briefly, in an earlier failed deploy attempt with a persisted volume), the password already on disk wins — use the console's own password-reset flow or clear the volume for a genuinely fresh start.
• Image pull / build failed: review Cloud Build history — container_image_source = "prebuilt" means no build step runs at all, so a failure here usually points at an Artifact Registry mirroring issue rather than a Dockerfile problem.
• 403 / permission errors: verify the runtime service account's IAM roles.

See the Configuration Guide's Configuration Pitfalls & Sensible Defaults section for setting-specific gotchas (including the no-DNS-resolver scoping decision and IAP recommendation).

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Task 6 — Tear down [Automated]

On the Deployments page, open the deployment and click the Trash icon (Delete). Delete runs terraform destroy and is irreversible (the deployment record is retained for history). If a deployment is stuck and the RAD platform can no longer manage it (for example after manual changes that conflict with the Terraform state), use Purge instead (from the same Delete dialog) — it removes the deployment from RAD's records without destroying the cloud resources (it makes RAD forget the deployment). This removes everything the module created — the Cloud Run service, the config Cloud Storage bucket, the admin-password secret, and Artifact Registry images. There is no Cloud SQL database to clean up (TechnitiumDNS provisions none). Resources owned by Services_GCP (the VPC, shared registry) are managed separately and are not removed here.

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Summary

Task	Type	Outcome
1 — Deploy	Automated	Module provisions a single Cloud Run service running the prebuilt TechnitiumDNS image, one config bucket, one secret
2 — Access & verify	Manual	Health check passes; first login succeeds; a zone/record survives a restart
3 — Operate	Manual	Inspect revisions, update version, manage secrets, enable IAP
4 — Observe	Manual	Query Cloud Logging; review Cloud Monitoring metrics and uptime check
5 — Troubleshoot	Manual	Diagnose revision, storage-persistence, and access issues; confirm no-DNS-resolver scoping
6 — Tear down	Automated	Delete (Trash) removes all module resources