Fly.io Upgrade & Migration

Overview

Guide for Fly.io platform migrations: Apps v1 (Nomad) to v2 (Machines), flyctl CLI upgrades, Postgres major version upgrades, and region migrations.

Prerequisites

• Current platform documentation and an inventory of applications, machines, regions, volumes, databases, identities, and dependent consumers.
• A staging environment, synthetic traffic/data, tested backup/restore, rollback owner, and explicit acceptance/reconciliation criteria.

Output

Produce a migration receipt with versions reviewed, affected resources, staging/canary results, backup/restore evidence, reconciliation outcome, approver, and rollback state. Keep tokens, connection strings, and user data out of the receipt.

Error Handling

• Stop promotion on health, schema, region, permission, or reconciliation mismatches and restore the prior configuration.
• Quarantine failed migrations by opaque resource ID; do not bulk replay stateful workloads to diagnose failures.
• Escalate potential data loss or credential exposure and retain only approved incident evidence.

Examples

Migrate a disposable staging app using synthetic traffic, exercise a backup/restore of fictional data, and simulate a failed health check. Verify rollback returns routing and data access to the known-good release before considering a production canary.

Instructions

Apps v1 to v2 Migration

# Check current platform version
fly status -a my-app  # Look for "Platform: machines" vs "nomad"

# Migrate to Apps v2 (Machines)
fly migrate-to-v2 -a my-app

# Verify
fly status -a my-app
fly machine list -a my-app

flyctl CLI Upgrade

# Check current version
fly version

# Upgrade
fly version update

# Or reinstall
curl -L https://fly.io/install.sh | sh

Postgres Major Version Upgrade

# Check current version
fly postgres connect -a my-db -c "SELECT version();"

# Create new cluster with target version
fly postgres create --name my-db-v16 --region iad --image-ref flyio/postgres-flex:16

# Migrate data
fly postgres import pg_dump_url -a my-db-v16

# Update app to point to new cluster
fly postgres detach my-db -a my-app
fly postgres attach my-db-v16 -a my-app
fly deploy -a my-app  # Picks up new DATABASE_URL

Region Migration

# Add machines in new region
fly scale count 1 --region fra -a my-app

# Verify new region is healthy
fly status -a my-app

# Remove machines from old region
fly scale count 0 --region iad -a my-app

# For volumes: create new volume, migrate data, destroy old
fly volumes create data --size 10 --region fra -a my-app

Migration Checklist

• [ ] Current state documented (fly status, fly scale show)
• [ ] Database backed up before migration
• [ ] Tested migration in staging app first
• [ ] DNS/certificates transferred if changing domains
• [ ] Monitoring confirms healthy after cutover
• [ ] Old resources cleaned up

Resources

• Apps v2 Migration
• Postgres Upgrades

Next Steps

For CI integration, see flyio-ci-integration.