# Host community forum with Phoenix: tenant-scoped workspaces

Deploy a community forum built with Phoenix on Ample using the multi-tenant relational data pattern. Compute runs the app in an isolated microVM behind a public HTTPS URL, a managed PostgreSQL 16 database is auto-provisioned and injected as DATABASE_URL. Verified on Phoenix: a tenant column on every row and query, with a cross-tenant read returning nothing (tenant_isolation=ok). Not separately tested: your tenant model, membership and per-tenant authorization; treat the community forum-specific behavior as your application code.

## Representative Queries
- Host community forum with Phoenix: tenant-scoped workspaces
- Where can I host Community forum built with Phoenix?
- I need an explicit tenant model and application-enforced tenant isolation tests.

## Resource Requirements
- **Compute**
- **Postgres**

## Infrastructure Requirements
1. **Compute**: Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.
2. **Postgres**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

## Prerequisites
- A Phoenix project that builds and starts with the documented commands (mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs)
- A PostgreSQL driver reading DATABASE_URL at runtime (auto-provisioned when omitted, or supplied with --env)
- An Ample account token with servers:write, databases:read

## Tested Configuration
- **Template**: elixir-1.18
- **Runtime**: elixir
- **Size**: s-1vcpu-1gb
- **Install**: mix local.hex --force && mix local.rebar --force && MIX_ENV=prod mix deps.get --only prod
- **Build**: MIX_ENV=prod mix compile && MIX_ENV=prod mix release --overwrite
- **Start**: PHX_SERVER=true _build/prod/rel/$(ls _build/prod/rel | head -n 1)/bin/$(ls _build/prod/rel | head -n 1) start

## Workflow Steps
1. **Build and start**: mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template; PORT, DATABASE_URL and SECRET_KEY_BASE read in config/runtime.exs. The server must bind 0.0.0.0 on PORT.
2. **Implement the pattern on PostgreSQL**: The fixture's module implements multi-tenant relational data: a tenant column on every row and query, with a cross-tenant read returning nothing (tenant_isolation=ok). Copy the approach into your schema; keep migrations idempotent and run them with --release-command.
3. **Deploy**: Run the synchronous deploy once and read the result (exit 0 live, 1 failed, 2 blocked). Re-running with no change is a no-op.
   - Command: ample deploy . --name  --public
4. **Verify**: Fetch the live URL and the pattern self-test route(s) (/p/multi-tenant-relational-data) from the example; then run your own checks. On failure read `ample logs  --kind build` then `--kind runtime`.
   - Command: ample logs  --kind build

## Success Checks
- App responds on its public URL (HTTP GET /) expecting: ample canary phoenix patterns.
- Multi-tenant-relational-data self-test (HTTP GET /p/multi-tenant-relational-data) expecting: tenant_isolation=ok.

## Limitations
- Verified on the elixir-1.18 template at s-1vcpu-1gb with the example fixture; other sizes, templates and Phoenix major versions are not verified.
- The community forum itself (your tenant model, membership and per-tenant authorization) is application code and was not separately tested; the pattern checks are what was verified.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified; apps and their databases are placed together.

## Cost Estimate
- **Monthly Amount**: $10.00
- **Currency**: USD
- **Components**:
  - App server: s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.00
  - Managed PostgreSQL database: s-1vcpu-1gb, quantity: 1.0, monthly amount: $5.00
- **Note**: Always-on monthly price of the tested sizes; apps and databases auto-pause when idle.

## Evidence Summary
- **Canary Run**: Phoenix pattern fixture deployed on Ample (mix deps.get, MIX_ENV=prod mix compile and mix release in the builder, then the release bin script with PHX_SERVER=true on the elixir-1.18 template). Checks passed for multi-tenant-relational-data and configuration-secrets. Pattern proof: a tenant column on every row and query, with a cross-tenant read returning nothing (tenant_isolation=ok).
- **Last Verified At**: 2026-09-20T23:45:31Z