Migrating from Atlantis

Atlantis pioneered Terraform PR automation. But after 1-2 years, most teams outgrow it. If you’re hitting Atlantis’s limits, Yaffle is the natural next step.

Why teams leave Atlantis

Pain point	Atlantis	Yaffle
Operational overhead	You run it: servers, updates, monitoring	Managed service, zero ops
Single-threaded	One run at a time, bottleneck on busy repos	Parallel runs across workspaces
No RBAC	Anyone with repo access can `atlantis apply`	Granular approval policies
No drift detection	Manual checks or external tooling	Built-in (planned)
Plan-only previews	Shows what would change, can’t test it	Real infrastructure you can hit
State management	You configure backends	Fully managed
Secrets	Environment variables or external tools	AWS Secrets Manager integration

What you’ll gain

Preview environments

Atlantis shows you a plan. Yaffle creates real infrastructure.

Atlantis:  PR → terraform plan → read diff → merge → hope it works
Yaffle:    PR → plan → apply preview → test it → merge → apply production

Your QA team can test against pr-42.staging.example.com before merge.

No more server management

Stop patching Atlantis servers, debugging webhook issues, and scaling infrastructure. Yaffle runs in our infrastructure—you just connect your repo.

Proper access control

Atlantis’s access model is “if you can push, you can apply.” Yaffle supports:

[[approvals]]
workspaces = ["infra/production/*"]
environments = ["production"]
approvers = [
  "github:team:acme/platform-engineering",
  "github:user:alice",
]

OpenTofu native

Yaffle runs OpenTofu, the open-source fork under MPL 2.0. No BSL licensing concerns as your infrastructure scales.

Migration path

Install Yaffle
Section titled “Install Yaffle”

Install the GitHub App on your repository. This doesn’t affect Atlantis—both can run simultaneously.

Add `yaffle.toml`

Create a config matching your Atlantis setup:

version = 1

[[environments]]
name = "production"

[[environments]]
name = "staging"

[[triggers.github.push]]
branch = "main"
environment = "production"

[[triggers.github.pull_request]]
branch_pattern = "*"

[[workspaces]]
path = "infra"
environments = ["*"]

Connect your AWS account
Section titled “Connect your AWS account”

Deploy the bootstrap module to create the IAM role Yaffle assumes.
Test on a PR
Section titled “Test on a PR”

Open a test PR. Both Atlantis and Yaffle will run. Compare results.
Disable Atlantis
Section titled “Disable Atlantis”

Once confident, remove the Atlantis webhook or uninstall the Atlantis GitHub App.

Configuration mapping

atlantis.yaml → yaffle.toml

Atlantis:

version: 3
projects:
  - name: network
    dir: infra/network
    workspace: default
    autoplan:
      when_modified: ["*.tf"]
      enabled: true
  - name: compute
    dir: infra/compute
    workspace: default

Yaffle:

version = 1

[[workspaces]]
path = "infra/network"
environments = ["*"]

[[workspaces]]
path = "infra/compute"
environments = ["*"]

Workflow commands

Atlantis command	Yaffle equivalent
`atlantis plan`	Automatic on PR push
`atlantis apply`	Automatic after plan (previews) or on merge (production)
`atlantis plan -d infra/network`	Plans all affected workspaces automatically
`atlantis unlock`	Not needed—Yaffle manages locking

Environment variables

Atlantis: Set in server environment or atlantis.yaml

Yaffle: Use the variables field or Secrets Manager:

[[workspaces]]
path = "infra"
environments = ["*"]
variables.region = "us-east-1"
secrets.db_password = "arn:aws:secretsmanager:us-east-1:123:secret:db-pass"

Running both during migration

You can run Atlantis and Yaffle simultaneously:

Both will post checks to PRs
Both will plan on push
Only one should apply—disable Atlantis autoplan for production

# atlantis.yaml - disable autoplan during migration
version: 3
projects:
  - name: infra
    dir: infra
    autoplan:
      enabled: false  # Manual only during migration

Once you’re confident in Yaffle, remove Atlantis entirely.

FAQ

Can I migrate incrementally?

Yes. Add specific workspaces to Yaffle while Atlantis handles others. Yaffle only manages workspaces defined in yaffle.toml.

What about existing state?

Yaffle manages its own state. Your existing Terraform state stays where it is. For new workspaces, Yaffle starts fresh. For existing resources, use tofu import.

Do I need to change my Terraform code?

No. Yaffle runs standard OpenTofu, which is compatible with Terraform configurations. Your .tf files work as-is.

What if something goes wrong?

Yaffle provides full run logs in the dashboard and GitHub checks. If a preview fails, it doesn’t affect production. If you need to rollback, revert your PR and Yaffle applies the previous state.