Excalidraw on Google Cloud Run

Excalidraw is an open-source (MIT) virtual whiteboard for sketching hand-drawn-style diagrams, wireframes, and quick collaborative drawings. The self-hosted distribution is a static single-page application served by nginx — there is no backend, database, or user accounts, and drawings are stored in the visitor's own browser. This module deploys that static frontend on Cloud Run v2 on top of the App_CloudRun foundation, which provisions and manages the shared Google Cloud infrastructure.

This guide focuses on the cloud services Excalidraw uses and how to explore and operate them from the Google Cloud Console and the command line. For the mechanics common to every Cloud Run application — service identity, ingress and load balancing, scaling and concurrency, CI/CD, Cloud Armor, IAP, Binary Authorization, VPC Service Controls, and the deployment lifecycle — refer to the App_CloudRun foundation guide rather than repeating them here.

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1. Overview

Excalidraw runs as a single stateless nginx container on Cloud Run v2. Because the app has no backend, the deployment wires together only a minimal set of Google Cloud services:

Capability	Google Cloud service	Notes
Compute	Cloud Run v2	Static nginx container on port 80, 1 vCPU / 512 MiB by default, serverless autoscaling; scale-to-zero enabled
Container image	Artifact Registry	Thin custom build FROM excalidraw/excalidraw, mirrored into the project registry
Database	None	Excalidraw has no backend — no Cloud SQL instance is created
Object storage	None	No GCS bucket is provisioned; drawings live in the browser
Cache & queue	None	No Redis, no message queue
Secrets	None	No encryption keys, JWT secrets, or DB passwords — Secret Manager is unused
Ingress	Cloud Run URL / Cloud Load Balancing	Default run.app URL; optional external HTTPS load balancer + custom domain

Sensible defaults worth knowing up front:

• Fully stateless — no data is stored server-side. Drawings persist in each browser's local storage and are exported/imported as .excalidraw files. Redeploys, scale-to-zero, and revision changes lose no server data because there is none.
• Scale-to-zero is forced on. The wrapper pins min_instance_count = 0; there is no background work to keep an instance warm, so idle deployments cost nothing. Cold starts are fast (nginx serving a static bundle) — typically sub-second.
• Request-based billing by default. cpu_always_allocated = false: CPU is billed only while a request is being served, appropriate for a static file server with no in-process background work.
• Fixed port 80. The nginx listener is baked into the image; container_port defaults to 80 and should not be changed.
• No Cloud SQL, Secret Manager, Redis, or GCS. The corresponding foundation features are inert for this app — enabling them provisions unused infrastructure.
• Public ingress by default. ingress_settings = "all" so the whiteboard is reachable from a browser. Front it with IAP or Cloud Armor if you need to restrict access.
• Vestigial homeserver_url / homeserver_name inputs. Carried over from the Element template and injected as HOMESERVER_URL / HOMESERVER_NAME; the Excalidraw static SPA ignores them. Leave them at their defaults.

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2. Google Cloud Services & How to Explore Them

All commands assume PROJECT and REGION are set. Service and resource names are reported in the deployment Outputs.

A. Cloud Run — the Excalidraw service

Excalidraw runs as a Cloud Run v2 service that autoscales by request load between the minimum (0) and maximum instance counts. Each deployment creates an immutable revision; traffic can be split across revisions for safe rollouts.

• Console: Cloud Run → select the service for revisions, traffic, logs, and metrics.
• CLI:

  gcloud run services list --project "$PROJECT" --region "$REGION" \
    --filter="metadata.name~excalidraw"
  gcloud run services describe <service-name> --project "$PROJECT" --region "$REGION"
  gcloud run revisions list --service <service-name> --project "$PROJECT" --region "$REGION"
  # Confirm the listening port and image on the running revision:
  gcloud run services describe <service-name> --region "$REGION" \
    --format='value(spec.template.spec.containers[0].ports[0].containerPort, spec.template.spec.containers[0].image)'

See App_CloudRun for scaling, concurrency, execution environment, and traffic splitting.

B. Artifact Registry — the container image

The Excalidraw image is a thin custom build FROM excalidraw/excalidraw that Cloud Build produces and pushes into the project's Artifact Registry (enable_image_mirroring = true). No Docker Hub pull is needed at runtime.

• Console: Artifact Registry → Repositories.
• CLI:

  gcloud artifacts repositories list --project "$PROJECT" --location "$REGION"
  gcloud artifacts docker images list <repo-path> --include-tags
  # Cloud Build history for the image build:
  gcloud builds list --project "$PROJECT" --region "$REGION" --limit 5

C. Database, Secret Manager, Cloud Storage, Redis — not used

Excalidraw provisions none of these. There is no Cloud SQL instance, no Secret Manager secret, no GCS bucket, and no Redis for this deployment. The following will return empty results for the app — that is expected:

gcloud sql instances list --project "$PROJECT" --filter="name~excalidraw"   # (none)
gcloud secrets list --project "$PROJECT" --filter="name~excalidraw"          # (none)
gcloud storage buckets list --project "$PROJECT" --filter="name~excalidraw"  # (none)

If you need multi-user real-time collaboration (a live shared canvas), Excalidraw requires a separate excalidraw-room WebSocket server, which this module does not deploy.

D. Networking & ingress

The service is reachable at its run.app URL by default. An external HTTPS load balancer with a custom domain, Cloud CDN, and Cloud Armor can be layered on; ingress settings and VPC egress control connectivity. Because the payload is static assets, Cloud CDN is a particularly good fit for reducing latency and cost.

• Console: Cloud Run (service URL); Network services → Load balancing.
• CLI:

  gcloud run services describe <service-name> --region "$REGION" --format='value(status.url)'
  gcloud compute addresses list --project "$PROJECT"

See App_CloudRun.

E. Cloud Logging & Monitoring

Container (nginx access/error) logs flow to Cloud Logging; Cloud Run metrics flow to Cloud Monitoring, with optional uptime checks and alert policies. A public root-path uptime check is a natural health signal for the static frontend.

• Console: Logging → Logs Explorer; Monitoring → Dashboards / Alerting.
• CLI:

  gcloud run services logs read <service-name> --project "$PROJECT" --region "$REGION" --limit 50

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3. Excalidraw Application Behaviour

• No first-deploy setup. There is no database, no init job, and no migrations. The service is ready as soon as nginx starts serving the static bundle — usually within a second or two of the revision becoming active.
• No accounts, no login, no server persistence. The self-hosted frontend has no authentication and stores nothing server-side. Each user's drawings live in their own browser's local storage; clearing browser data loses local drawings. Use Export (.excalidraw, PNG, or SVG) to save or share work.
• Real-time collaboration is not included. The live "shareable link" collaboration feature depends on a separate excalidraw-room WebSocket service that this module does not deploy. Single-user editing works out of the box.
• Health path. Startup and liveness probes target the root /, which nginx answers with 200 immediately. Verify from a browser or:

  SERVICE_URL=$(gcloud run services describe <service-name> \
    --region "$REGION" --project "$PROJECT" --format='value(status.url)')
  curl -sI "$SERVICE_URL/" | head -1          # expect: HTTP/2 200

• Version upgrades are a rebuild + redeploy. Bumping application_version rebuilds the image from a new excalidraw/excalidraw tag and rolls out a new revision; because there is no state, upgrades and rollbacks are trivial and non-destructive.
• Vestigial env vars. HOMESERVER_URL / HOMESERVER_NAME are injected (Element carry-over) but ignored by the static SPA. Setting them has no effect.

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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 Excalidraw are listed; every other input is inherited from App_CloudRun with its standard behaviour.

Group 3 — Application Identity

Variable	Default	Description
application_name	excalidraw	Base name for resources. Do not change after first deploy.
application_version	latest	Excalidraw image tag; resolves to a pinned known-good tag when latest. Pin a specific release in production.
homeserver_url / homeserver_name	""	Vestigial Element carry-over — ignored by the Excalidraw SPA. Leave blank.

All other inputs follow standard App_CloudRun behaviour.

Group 4 — Runtime & Scaling

Variable	Default	Description
deploy_application	true	Set false to provision infrastructure only.
container_image_source	custom	Keep custom — the thin build mirrors the static image into Artifact Registry.
cpu_limit	1000m	CPU per instance; a static file server needs little.
memory_limit	512Mi	Memory per instance. Gen2 imposes a 512 MiB floor; the static bundle uses far less.
cpu_always_allocated	false	Request-based billing — correct for a static server with no background work.
container_port	80	nginx listener port; baked into the image — do not change.
min_instance_count	0	Forced to 0 by the wrapper — scale-to-zero, no warm instance needed.
max_instance_count	3	Cost/concurrency ceiling.
enable_image_mirroring	true	Mirror the Excalidraw image into Artifact Registry.

All other inputs follow standard App_CloudRun behaviour.

Group 6 — Environment Variables & Secrets

Variable	Default	Description
environment_variables	{}	Extra plain-text env vars. The static SPA reads none at runtime; overrides are rarely useful.
secret_environment_variables	{}	Unused — Excalidraw needs no secrets.

All other inputs follow standard App_CloudRun behaviour.

Group 5 — Access & Ingress Control

Variable	Default	Description
ingress_settings	all	Public access so the whiteboard is browser-reachable.
enable_iap	false	Put Google sign-in in front of Excalidraw to restrict access.

All other inputs follow standard App_CloudRun behaviour.

Groups 10–21 — Storage, Database, Redis

These groups are inert for Excalidraw: there is no database (database_type = NONE), no GCS bucket, and no Redis. Leaving enable_nfs, enable_redis, create_cloud_storage, and the database inputs at their defaults provisions no unused infrastructure. All other inputs follow standard App_CloudRun behaviour.

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5. Outputs

Returned on a successful deployment — the quickest way to locate and explore the running resources. Storage/database/secret outputs are present for interface parity with other modules but resolve to empty values here.

Output	Description
service_name	Cloud Run service name.
service_url	Default run.app URL of the service.
service_location	Region the service runs in.
stage_services	Stage-specific service details (Cloud Deploy).
load_balancer_ip / load_balancer_url	External HTTPS load balancer IP / URL (when enabled).
storage_buckets	Created Cloud Storage buckets — empty for Excalidraw.
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 / uptime_check_names	Monitoring status, channels, uptime checks.
initialization_jobs	Setup job names — empty for Excalidraw.
deployment_id / tenant_id / resource_prefix	Naming identifiers.
project_id / project_number	Project identifiers.
cicd_enabled / github_repository_url / github_repository_owner / github_repository_name / cicd_configuration	CI/CD status and details.
artifact_registry_repository / cloudbuild_trigger_name / cloudbuild_trigger_id	Registry and build trigger.
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_CloudRun foundation engine, which validates values and combinations at plan time — an out-of-range port, a gen1 runtime with NFS/GCS mounts, IAP with no authorized identities. Invalid configuration fails the plan with a clear, named error before any resource is created.

Setting	Sensible value	Risk	Consequence if wrong
container_port	80	High	The image's nginx listens only on 80; a mismatched port means the startup probe never passes and the revision never serves.
container_image_source	custom	High	Switching to prebuilt without a mirrored image points the service at an unbuilt Artifact Registry path (Image not found).
memory_limit	512Mi	Medium	Gen2 rejects < 512Mi at apply; the static bundle needs no more.
ingress_settings	all	Medium	internal makes the whiteboard unreachable from a browser outside the VPC.
application_version	pin in production	Medium	latest floats — a new upstream tag can change UI/behaviour on the next rebuild. Pin a release.
enable_redis / database inputs	leave default	Low	Enabling them provisions Redis/Cloud SQL that Excalidraw never uses — wasted cost, no benefit.
homeserver_url / homeserver_name	leave blank	Low	Vestigial Element inputs; setting them has no effect on the Excalidraw SPA.
min_instance_count	0	Low	Scale-to-zero is ideal here; forcing > 0 only adds idle cost with no state to keep warm.

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For the foundation behaviour referenced throughout — service identity, scaling and concurrency, ingress and load balancing, CI/CD, Cloud CDN, Cloud Armor, IAP, Binary Authorization, VPC-SC, and image mirroring — see App_CloudRun. Excalidraw-specific application configuration shared with the GKE variant is described in Excalidraw_Common.