RonanCodes/fly-deploy

Fly.io Deploy

Ship Docker containers to Fly.io using flyctl. Covers launch, deploy, status, logs, secrets, scaling, and custom domains.

Usage

/ro:fly-deploy launch                    # first-time scaffold for this repo
/ro:fly-deploy deploy                    # build + push + release
/ro:fly-deploy status                    # current machines + health
/ro:fly-deploy logs [--tail]
/ro:fly-deploy secrets set KEY=value ...
/ro:fly-deploy certs add api.myapp.com   # custom domain (pairs with /ro:cloudflare-dns)

Prerequisites

• flyctl installed — if missing: brew install flyctl (macOS) or curl -L https://fly.io/install.sh | sh
• Authenticated — check flyctl auth whoami. If not authed, use one of:
  • flyctl auth login (browser, interactive)
  • Org token (preferred for agentic use): set FLY_ORG_TOKEN in ~/.claude/.env. Generate at https://fly.io/dashboard → your org → Access Tokens → Create Org Token
  • Personal access token (wider scope, avoid): set FLY_API_TOKEN in ~/.claude/.env. Generate at https://fly.io/user/personal_access_tokens
• A Dockerfile in the project (or use flyctl launch to generate one)

Token scope (important)

This skill is designed around an organization-scoped token (FLY_ORG_TOKEN) — lower blast radius than a personal access token.

| Capability | Org token | Personal token | |---|---|---| | Deploy, read, write, manage secrets within its own org | ✅ | ✅ | | Access multiple orgs | ❌ (token is pinned to one org) | ✅ | | Create new orgs / manage billing | ❌ | ✅ | | Appropriate for agent automation | ✅ | ⚠️ overly broad |

flyctl natively reads FLY_API_TOKEN only, so the skill shadows it at invocation:

export FLY_API_TOKEN="${FLY_ORG_TOKEN:-${FLY_API_TOKEN}}"

The skill verifies the token before any destructive-ish command by running flyctl auth whoami and reporting token: Organization Token so the user can confirm they're about to act with the scope they expect.

Process

First-time launch

flyctl launch --no-deploy          # generates fly.toml, asks region + org

Review the generated fly.toml before deploying:

• app — globally unique name (becomes <app>.fly.dev)
• primary_region — closest to users (e.g. lhr, iad, sjc)
• [http_service] — internal_port must match the container's listen port
• [[vm]] — size (default shared-cpu-1x / 256MB — bump for FE builds with SSR)

Then: flyctl deploy.

Subsequent deploys

flyctl deploy --remote-only        # build on Fly's builders (no local Docker needed)

Flags to know:

• --strategy immediate — replace all machines at once (dev only)
• --strategy rolling — default, zero downtime
• --ha=false — single machine only (cheaper for staging)
• --dockerfile <path> — non-default Dockerfile
• --build-arg KEY=value — build-time args

Infrastructure docs (post-first-deploy)

After a successful deploy, if docs/infrastructure/ is absent (first deploy) or the deploy changed apps/volumes/secrets/machines, run /ro:infra-docs to generate or refresh the living architecture docs (live resource inventory, C4 + sequence diagrams, security model, provisioning runbook). It discovers live Fly state via flyctl. Idempotent, so re-run after notable deploys.

Status & logs

flyctl status -a <app>             # machine list, regions, health
flyctl logs -a <app>               # stream logs
flyctl releases -a <app>           # deploy history
flyctl ssh console -a <app>        # shell into a running machine

Secrets

Secrets are baked into the container env at runtime (restarts machines):

flyctl secrets set DATABASE_URL=postgres://... STRIPE_KEY=sk_... -a <app>
flyctl secrets list -a <app>
flyctl secrets unset OLD_VAR -a <app>

Never paste secrets into fly.toml — use flyctl secrets set.

Custom domains (subdomain on Cloudflare)

flyctl certs create api.myapp.com -a <app>
flyctl certs show api.myapp.com -a <app>     # shows required DNS + validation status
flyctl ips list -a <app>                     # A/AAAA targets if you prefer A over CNAME

Then chain with /ro:cloudflare-dns to add the records. Poll certs show until status is Issued (usually 30s–2min).

Scaling

flyctl scale count 2 -a <app>             # horizontal (machines)
flyctl scale vm shared-cpu-2x -a <app>    # vertical (CPU/RAM preset)
flyctl scale memory 1024 -a <app>         # memory only

Cost sizing cheatsheet

shared-cpu-1x machine pricing (approx, Amsterdam tier — other regions have small multipliers):

| Memory | $/month (always on) | $/hour | |--------|---------------------|--------| | 256MB | $2.02 | $0.0028 | | 512MB | $3.32 | $0.0046 | | 1GB | $5.92 | $0.0082 | | 2GB | $11.11 | $0.0154 |

• Stopped machine: rootfs only — ~$0.15/GB-month of image size. For a 65MB image ≈ $0.01/mo.
• Volume: $0.15/GB-month. Minimum size is 1GB — you cannot shrink below it, and fly volumes extend only goes up. Plan sizes carefully.
• Scale to zero (auto_stop_machines="suspend" + min_machines_running=0) → you only pay compute while serving. A personal tool typically costs $0.30–$1/mo all-in.

suspend vs stop (both free of extra cost)

| Mode | Cold start | When to use | |------|-----------|-------------| | suspend | ~200ms (keeps memory snapshot) | Default for most apps — UX win at zero cost | | stop | ~1-3s | Long-idle apps or edge cases where snapshots misbehave |

Live pricing: https://fly.io/docs/about/pricing/

Common failure modes

• "App not found" — wrong -a, or token is pinned to a different org than the app lives in. Run flyctl orgs list to confirm the token's org. Org tokens cannot reach apps in other orgs.
• "You must be authenticated" via API/GraphQL — FLY_API_TOKEN isn't shadowed from FLY_ORG_TOKEN. Check with echo "${FLY_API_TOKEN:-unset}".
• Build OOM — bump builder with flyctl deploy --vm-memory 2048 or upgrade machine size
• Healthcheck fails — internal_port in fly.toml doesn't match what the container listens on
• Cert stuck in awaiting_configuration — DNS record missing or wrong proxied flag (Fly needs unproxied / grey-cloud on Cloudflare for TLS termination)

Safety

• flyctl apps destroy and flyctl machine destroy are irreversible — always confirm with the user first
• flyctl deploy to a prod app: show the user the current release and the new image tag before shipping
• Never commit fly.toml with hardcoded secrets — use [env] for non-secret config only

See also

• /ro:cloudflare-dns — add the subdomain after certs create
• Fly docs: https://fly.io/docs — use context7 if fetching current syntax