Import Existing Cloud Resources

Intermediate15 minTrending

Bring existing cloud resources under Terraform management without recreating or disrupting them.

Prerequisites

-Terraform installed
-Existing cloud resources to import
-Cloud provider credentials configured

Steps

Write the resource block for the existing resource

Define a resource block in your configuration that matches the existing cloud resource's type and settings.

$ cat <<'EOF' > imported.tf resource "aws_s3_bucket" "existing" { bucket = "my-existing-bucket" } EOF

Check the provider documentation for all required and optional arguments for the resource type.

Import the resource into state

Run terraform import to associate the existing resource with your new resource block in state.

$ terraform import aws_s3_bucket.existing my-existing-bucket

Import only updates state. If your configuration does not match the real resource, the next apply will modify it.

Generate a plan to find config drift

Run plan to see what differences exist between your written config and the actual resource attributes.

$ terraform plan

Adjust configuration until plan is clean

Update your .tf file to match the real resource attributes until terraform plan shows no changes.

$ terraform plan -detailed-exitcode

Exit code 0 means no changes. Exit code 2 means there are still differences to resolve.

Use import blocks for bulk import (Terraform 1.5+)

For Terraform 1.5 and later, use declarative import blocks to import multiple resources in one apply.

$ cat <<'EOF' >> imported.tf import { to = aws_s3_bucket.existing id = "my-existing-bucket" } EOF terraform plan -generate-config-out=generated.tf

The -generate-config-out flag auto-generates the resource config for you, saving manual work.

Full Script

full-script.sh

#!/bin/bash
set -euo pipefail

# Terraform Import Script
# Imports an existing AWS resource into Terraform state

RESOURCE_TYPE="${1:?Usage: $0 <resource_type> <resource_name> <resource_id>}"
RESOURCE_NAME="${2:?Usage: $0 <resource_type> <resource_name> <resource_id>}"
RESOURCE_ID="${3:?Usage: $0 <resource_type> <resource_name> <resource_id>}"

ADDR="${RESOURCE_TYPE}.${RESOURCE_NAME}"

echo "==> Importing ${ADDR} (id: ${RESOURCE_ID})..."
terraform import "${ADDR}" "${RESOURCE_ID}"

echo "==> Checking for configuration drift..."
terraform plan -detailed-exitcode 2>&1 | tee /tmp/tf-import-plan.txt || {
  EXIT_CODE=$?
  if [ "$EXIT_CODE" -eq 2 ]; then
    echo ""
    echo "WARNING: Configuration does not match imported resource."
    echo "Review the plan output above and update your .tf files."
    echo "Run 'terraform plan' again after making changes."
  fi
}

echo ""
echo "==> Current state for imported resource:"
terraform state show "${ADDR}"

FAQ

Discussion

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#!/bin/bash set -euo pipefail # Terraform Import Script # Imports an existing AWS resource into Terraform state RESOURCE_TYPE="${1:?Usage: $0 <resource_type> <resource_name> <resource_id>}" RESOURCE_NAME="${2:?Usage: $0 <resource_type> <resource_name> <resource_id>}" RESOURCE_ID="${3:?Usage: $0 <resource_type> <resource_name> <resource_id>}" ADDR="${RESOURCE_TYPE}.${RESOURCE_NAME}" echo "==> Importing ${ADDR} (id: ${RESOURCE_ID})..." terraform import "${ADDR}" "${RESOURCE_ID}" echo "==> Checking for configuration drift..." terraform plan -detailed-exitcode 2>&1 | tee /tmp/tf-import-plan.txt || { EXIT_CODE=$? if [ "$EXIT_CODE" -eq 2 ]; then echo "" echo "WARNING: Configuration does not match imported resource." echo "Review the plan output above and update your .tf files." echo "Run 'terraform plan' again after making changes." fi } echo "" echo "==> Current state for imported resource:" terraform state show "${ADDR}"