Secrets Manager

AWS Secrets Manager

AWS Secrets Manager helps protect access to applications, services, and IT resources. Store, retrieve, and automatically rotate credentials, API keys, and other secrets.

Table of Contents

• Core Concepts
• Common Patterns
• CLI Reference
• Best Practices
• Troubleshooting
• References

Core Concepts

Secrets

Encrypted data stored in Secrets Manager. Can contain:

• Database credentials
• API keys
• OAuth tokens
• Any key-value pairs (up to 64 KB)

Versions

Each secret can have multiple versions:

• AWSCURRENT: Current active version
• AWSPENDING: Version being rotated to
• AWSPREVIOUS: Previous version

Rotation

Automatic credential rotation using Lambda functions. Built-in support for:

• Amazon RDS
• Amazon Redshift
• Amazon DocumentDB
• Custom secrets

Common Patterns

Create a Secret

AWS CLI:

bashCopy code
# Create secret with JSON
aws secretsmanager create-secret \
  --name prod/myapp/database \
  --description "Production database credentials" \
  --secret-string '{"username":"admin","password":"MySecurePassword123!","host":"mydb.cluster-xyz.us-east-1.rds.amazonaws.com","port":5432,"database":"myapp"}'

# Create secret with binary data
aws secretsmanager create-secret \
  --name prod/myapp/certificate \
  --secret-binary fileb://certificate.pem

boto3:

pythonCopy code
import boto3
import json

secrets = boto3.client('secretsmanager')

response = secrets.create_secret(
    Name='prod/myapp/database',
    Description='Production database credentials',
    SecretString=json.dumps({
        'username': 'admin',
        'password': 'MySecurePassword123!',
        'host': 'mydb.cluster-xyz.us-east-1.rds.amazonaws.com',
        'port': 5432,
        'database': 'myapp'
    }),
    Tags=[
        {'Key': 'Environment', 'Value': 'production'},
        {'Key': 'Application', 'Value': 'myapp'}
    ]
)

Retrieve a Secret

pythonCopy code
import boto3
import json

secrets = boto3.client('secretsmanager')

def get_secret(secret_name):
    response = secrets.get_secret_value(SecretId=secret_name)

    if 'SecretString' in response:
        return json.loads(response['SecretString'])
    else:
        import base64
        return base64.b64decode(response['SecretBinary'])

# Usage
credentials = get_secret('prod/myapp/database')
db_password = credentials['password']

Caching Secrets

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from aws_secretsmanager_caching import SecretCache, SecretCacheConfig

# Configure cache
cache_config = SecretCacheConfig(
    max_cache_size=100,
    secret_refresh_interval=3600,
    secret_version_stage_refresh_interval=3600
)

cache = SecretCache(config=cache_config)

def get_cached_secret(secret_name):
    secret = cache.get_secret_string(secret_name)
    return json.loads(secret)

Update a Secret

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# Update secret value
aws secretsmanager update-secret \
  --secret-id prod/myapp/database \
  --secret-string '{"username":"admin","password":"NewPassword456!"}'

# Put new version with staging labels
aws secretsmanager put-secret-value \
  --secret-id prod/myapp/database \
  --secret-string '{"username":"admin","password":"NewPassword456!"}' \
  --version-stages AWSCURRENT

Enable Rotation for RDS

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aws secretsmanager rotate-secret \
  --secret-id prod/myapp/database \
  --rotation-lambda-arn arn:aws:lambda:us-east-1:123456789012:function:SecretsManagerRDSPostgreSQLRotation \
  --rotation-rules AutomaticallyAfterDays=30

Create Secret with Rotation

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# Use CloudFormation for RDS secret with rotation
aws cloudformation deploy \
  --template-file rds-secret.yaml \
  --stack-name rds-secret

yamlCopy code
# rds-secret.yaml
AWSTemplateFormatVersion: '2010-09-09'
Resources:
  DBSecret:
    Type: AWS::SecretsManager::Secret
    Properties:
      Name: prod/myapp/database
      GenerateSecretString:
        SecretStringTemplate: '{"username": "admin"}'
        GenerateStringKey: password
        PasswordLength: 32
        ExcludeCharacters: '"@/\'

  DBSecretRotation:
    Type: AWS::SecretsManager::RotationSchedule
    Properties:
      SecretId: !Ref DBSecret
      RotationLambdaARN: !GetAtt RotationLambda.Arn
      RotationRules:
        AutomaticallyAfterDays: 30

Use in Lambda with Extension

pythonCopy code
import json
import urllib.request

def handler(event, context):
    # Use AWS Parameters and Secrets Lambda Extension
    secrets_port = 2773
    secret_name = 'prod/myapp/database'

    url = f'http://localhost:{secrets_port}/secretsmanager/get?secretId={secret_name}'
    headers = {'X-Aws-Parameters-Secrets-Token': os.environ['AWS_SESSION_TOKEN']}

    request = urllib.request.Request(url, headers=headers)
    response = urllib.request.urlopen(request)
    secret = json.loads(response.read())['SecretString']

    credentials = json.loads(secret)
    return credentials

CLI Reference

Secret Management

Versions

Rotation

Best Practices

Secret Organization

• Use hierarchical names: environment/application/secret-type
• Tag secrets for organization and cost allocation
• Separate by environment (dev, staging, prod)

Security

• Use resource policies to control access
• Enable encryption with customer-managed KMS keys
• Rotate secrets regularly (30-90 days)
• Audit access with CloudTrail
• Use VPC endpoints for private access

Access Control

jsonCopy code
{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "secretsmanager:GetSecretValue",
        "secretsmanager:DescribeSecret"
      ],
      "Resource": "arn:aws:secretsmanager:us-east-1:123456789012:secret:prod/*",
      "Condition": {
        "StringEquals": {
          "secretsmanager:ResourceTag/Environment": "production"
        }
      }
    }
  ]
}

Application Integration

• Cache secrets to reduce API calls
• Handle rotation gracefully (retry with new credentials)
• Use Lambda extension for faster access
• Never log secrets

Troubleshooting

AccessDeniedException

Causes:

• IAM policy missing secretsmanager:GetSecretValue
• Resource policy denying access
• KMS key policy missing permissions

Debug:

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# Check secret resource policy
aws secretsmanager get-resource-policy --secret-id my-secret

# Check IAM permissions
aws iam simulate-principal-policy \
  --policy-source-arn arn:aws:iam::123456789012:role/my-role \
  --action-names secretsmanager:GetSecretValue \
  --resource-arns arn:aws:secretsmanager:us-east-1:123456789012:secret:my-secret

Rotation Failed

Debug:

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# Check rotation status
aws secretsmanager describe-secret --secret-id my-secret

# Check Lambda logs
aws logs filter-log-events \
  --log-group-name /aws/lambda/SecretsManagerRotation \
  --filter-pattern "ERROR"

Common causes:

• Lambda timeout (increase to 30+ seconds)
• Network connectivity (VPC configuration)
• Database connection issues
• Wrong secret format

Secret Not Found

bashCopy code
# List secrets to find correct name
aws secretsmanager list-secrets \
  --filters Key=name,Values=myapp

# Check if deleted (within recovery window)
aws secretsmanager list-secrets \
  --include-planned-deletion

References

• Secrets Manager User Guide
• Secrets Manager API Reference
• Secrets Manager CLI Reference
• boto3 Secrets Manager