Configuring Policies

For background on policy concepts, types, and engines, see the Policies concept page.

Prerequisites

Before starting, ensure you have:

An existing Nuon app with at least one component (terraform, helm, or container_image)
The Nuon CLI installed and authenticated
Basic familiarity with OPA Rego syntax

Create the Policy Directory Structure

Create a policies/ directory in your app root to store policy files:

mkdir policies

Your final directory structure will look like this:

myapp/
├── policies/
│   ├── require-signed-images.rego
│   ├── require-encryption.rego
│   └── require-resource-limits.rego
├── policies.toml
├── components/
│   ├── api_image.toml
│   ├── database.toml
│   └── api.toml
└── metadata.toml

Add a Container Image Policy (Build-time)

Container image policies validate external images during the build phase. This example requires all images to be cryptographically signed. Create policies/require-signed-images.rego:

policies/require-signed-images.rego

package nuon

default allow := false

allow if {
    input.metadata.signed == true
}

deny contains msg if {
    not input.metadata.signed
    msg := sprintf("Image %s:%s must be signed", [input.image, input.tag])
}

For detailed container image policy patterns including SBOM validation and attestation checks, see the External Image Policies guide.

Add a Terraform Policy (Deploy-time)

Terraform policies validate the Terraform plan before applying changes. This example requires S3 bucket encryption and warns about missing tags. Create policies/require-encryption.rego:

policies/require-encryption.rego

package nuon

# Deny unencrypted S3 buckets
deny contains msg if {
    some resource in input.plan.resource_changes
    resource.type == "aws_s3_bucket"
    resource.change.actions[_] in ["create", "update"]
    not resource.change.after.server_side_encryption_configuration
    msg := sprintf("S3 bucket '%s' must have encryption enabled", [resource.address])
}

# Warn about missing Environment tag
warn contains msg if {
    some resource in input.plan.resource_changes
    resource.change.actions[_] in ["create", "update"]
    not resource.change.after.tags.Environment
    msg := sprintf("Resource '%s' is missing Environment tag", [resource.address])
}

Add a Helm Chart Policy (Deploy-time)

Helm chart policies validate rendered Kubernetes manifests. This example requires CPU and memory limits on all containers. Create policies/require-resource-limits.rego:

policies/require-resource-limits.rego

package nuon

# Deny containers without resource limits
deny contains msg if {
    input.review.kind.kind == "Pod"
    some container in input.review.object.spec.containers
    not container.resources.limits.cpu
    msg := sprintf("Container '%s' must have CPU limits defined", [container.name])
}

deny contains msg if {
    input.review.kind.kind == "Pod"
    some container in input.review.object.spec.containers
    not container.resources.limits.memory
    msg := sprintf("Container '%s' must have memory limits defined", [container.name])
}

# Warn about missing resource requests
warn contains msg if {
    input.review.kind.kind == "Pod"
    some container in input.review.object.spec.containers
    not container.resources.requests
    msg := sprintf("Container '%s' should have resource requests defined", [container.name])
}

Configure policies.toml

Create policies.toml at your app root to register each policy:

policies.toml

# Container image policy - evaluated at build time
[[policy]]
type       = "container_image"
engine     = "opa"
components = ["api_image"]
contents   = "./policies/require-signed-images.rego"

# Terraform policy - evaluated at deploy time
[[policy]]
type       = "terraform_module"
engine     = "opa"
components = ["*"]
contents   = "./policies/require-encryption.rego"

# Helm chart policy - evaluated at deploy time
[[policy]]
type       = "helm_chart"
engine     = "opa"
components = ["api"]
contents   = "./policies/require-resource-limits.rego"

Policy configuration fields

Field	Required	Description
`type`	Yes	Policy type: `container_image`, `helm_chart`, `kubernetes_manifest`, `terraform_module`, `kubernetes_cluster`, or `sandbox`
`engine`	No	Policy engine: `opa` or `kyverno` (default)
`name`	No	Human-readable name. If not specified, derived from the filename
`components`	Yes	List of component names this policy applies to. Use `["*"]` for all components of the specified type
`contents`	Yes	Inline policy content or path to policy file (e.g., `./policies/require-encryption.rego`)

The contents field supports multiple source types. Relative paths are resolved from the policies/ directory:

# Relative file path (relative to policies/ directory)
contents = "./require-encryption.rego"

# HTTP/HTTPS URL
contents = "https://example.com/policies/security.rego"

# Git repository (the `//` separates the repo from the path to the file)
contents = "git::https://github.com/org/policies//terraform/encryption.rego"

# Git repository, pinned to a ref (branch, tag, or commit)
contents = "git::https://github.com/org/policies//terraform/encryption.rego?ref=v1.2.3"

Sync Your App

Upload your policies by syncing your app:

nuon apps sync

Policies are synced along with components and other configuration. You should see output confirming the policies were uploaded:

Syncing app...
✓ Synced 3 policies
✓ Synced 3 components
✓ App sync complete

Observe Build-Time Evaluation

Container image policies are evaluated when you create a build. Trigger a build for your image component:

nuon builds create -c api_image

If the image is not signed, the build fails with policy_failed status:

Creating build for api_image...
✗ Build failed: policy check failed
  - require-signed-images: Image nginx:latest must be signed

If the image passes all policy checks, the build succeeds:

Creating build for api_image...
✓ Build created: bld_abc123
✓ Policy checks passed

Observe Deploy-Time Evaluation

Terraform and Helm policies are evaluated during deployment. Deploy your components to an install:

nuon installs deploy -i <install-id>

After the deployment starts, list the workflow steps to see policy results:

nuon installs workflows steps list -w <workflow-id>

The output shows policy status for each step:

Step              Status    Policy
deploy-database   error     ✗ 1
deploy-api        success   ⚠ 2

✗ indicates deny violations that blocked the step
⚠ indicates warnings that were logged but allowed the step to continue
✓ indicates all policies passed

Get detailed violation messages for a specific step:

nuon installs workflows steps get -w <workflow-id> -s <step-id>

Step: deploy-database
Status: error

Policy Violations:
  ✗ require-encryption: S3 bucket 'module.db.aws_s3_bucket.backup' must have encryption enabled

Policy Warnings:
  ⚠ require-encryption: Resource 'module.db.aws_rds_cluster.main' is missing Environment tag

View Results in Dashboard

Policy results are also visible in the Nuon Dashboard:

Navigate to your install’s Workflows tab
Select the workflow run
Click on a workflow step to view details
The Policy Report card shows:
- Passed: Green checkmark if all policies passed
- Denies: Red indicators with violation messages
- Warnings: Orange indicators with warning messages

Each violation displays the policy name and the specific message from your deny or warn rule.

You can also view policy results via CLI using nuon installs workflows steps get -w <workflow-id> -s <step-id>.

Fix Policy Violations

To resolve policy violations, update your components to comply with the policies: For container images: Sign your images using cosign or another signing tool before pushing to your registry. For Terraform: Add the required configuration to your module:

resource "aws_s3_bucket" "backup" {
  bucket = "my-backup-bucket"

  tags = {
    Environment = "production"
  }
}

resource "aws_s3_bucket_server_side_encryption_configuration" "backup" {
  bucket = aws_s3_bucket.backup.id

  rule {
    apply_server_side_encryption_by_default {
      sse_algorithm = "AES256"
    }
  }
}

For Helm charts: Add resource limits to your pod specs:

containers:
  - name: api
    resources:
      limits:
        cpu: "500m"
        memory: "512Mi"
      requests:
        cpu: "100m"
        memory: "128Mi"

After making changes, sync and redeploy:

nuon apps sync
nuon installs deploy -i <install-id>

Confirm the policies now pass:

Step              Status    Policy
deploy-database   success   ✓
deploy-api        success   ✓

Next Steps

External Image Policies - Advanced patterns for container image validation including SBOM, attestations, and signature verification
Example Policies Repository - Ready-to-use policy examples for Terraform and Kubernetes
Policies Configuration Reference - Complete schema reference for policy configuration

Connect Your App

Install with a Customer

Day 2 Operations

Integrations

Advanced

Prerequisites

Create the Policy Directory Structure

Add a Container Image Policy (Build-time)

Add a Terraform Policy (Deploy-time)

Add a Helm Chart Policy (Deploy-time)

Configure policies.toml

Policy configuration fields

Sync Your App

Observe Build-Time Evaluation

Observe Deploy-Time Evaluation

View Results in Dashboard

Fix Policy Violations

Next Steps

​Prerequisites

​Create the Policy Directory Structure

​Add a Container Image Policy (Build-time)

​Add a Terraform Policy (Deploy-time)

​Add a Helm Chart Policy (Deploy-time)

​Configure policies.toml

​Policy configuration fields

​Sync Your App

​Observe Build-Time Evaluation

​Observe Deploy-Time Evaluation

​View Results in Dashboard

​Fix Policy Violations

​Next Steps

Prerequisites

Create the Policy Directory Structure

Add a Container Image Policy (Build-time)

Add a Terraform Policy (Deploy-time)

Add a Helm Chart Policy (Deploy-time)

Configure policies.toml

Policy configuration fields

Sync Your App

Observe Build-Time Evaluation

Observe Deploy-Time Evaluation

View Results in Dashboard

Fix Policy Violations

Next Steps