Multi-account event notifications in AWS enable organizations to centralize monitoring and respond to events across multiple AWS accounts within their organization. This capability is essential for enterprises managing complex multi-account architectures using AWS Organizations.
AWS EventBridge se…Multi-account event notifications in AWS enable organizations to centralize monitoring and respond to events across multiple AWS accounts within their organization. This capability is essential for enterprises managing complex multi-account architectures using AWS Organizations.
AWS EventBridge serves as the primary service for implementing cross-account event notifications. Organizations can configure event buses to receive events from member accounts and route them to a central management account. This pattern allows security teams to aggregate CloudTrail events, Config rule compliance changes, and GuardDuty findings in one location.
To implement multi-account event notifications, you must establish resource-based policies on the target event bus that permit source accounts to send events. The source accounts then create rules that forward specific events to the destination account's event bus ARN. AWS Organizations integration simplifies this by allowing organization-wide permissions.
SNS topics also support cross-account notifications. By configuring appropriate access policies, SNS topics in a central account can receive messages from Lambda functions, CloudWatch Alarms, or other services in member accounts. This approach works well for operational alerts and automated remediation workflows.
Common use cases include centralized security monitoring where GuardDuty findings from all accounts flow to a security account, compliance reporting where Config rule evaluations aggregate for audit purposes, and cost management where billing alerts consolidate in a finance account.
Best practices involve using AWS Organizations SCPs to enforce event forwarding requirements, implementing least-privilege access policies, and creating separate event buses for different event categories such as security versus operational events. Organizations should also consider event filtering at the source to reduce noise and costs.
CloudFormation StackSets can automate the deployment of event rules across all member accounts, ensuring consistent configuration. This infrastructure-as-code approach maintains governance standards while enabling rapid scaling as new accounts join the organization.
Multi-Account Event Notifications - AWS Solutions Architect Professional Guide
Why Multi-Account Event Notifications Matter
In enterprise environments, organizations typically operate multiple AWS accounts for security isolation, billing separation, and workload segregation. Multi-account event notifications enable centralized monitoring, automated responses, and coordinated actions across these distributed environments. This capability is essential for maintaining governance, compliance, and operational efficiency at scale.
What Are Multi-Account Event Notifications?
Multi-account event notifications refer to the architectural patterns and AWS services used to capture, route, and process events across multiple AWS accounts within an organization. These events can include:
- Security findings and compliance violations - Resource state changes - Operational alerts and metrics - Application-level events - Infrastructure changes and deployments
Key AWS Services for Multi-Account Event Notifications
Amazon EventBridge EventBridge serves as the primary event bus for cross-account event routing. Key features include: - Cross-account event bus sharing via resource-based policies - Event rules that filter and route events to targets - Support for custom event buses dedicated to specific use cases - Integration with AWS Organizations for organization-wide event collection
Amazon SNS (Simple Notification Service) SNS enables cross-account topic subscriptions and notifications: - Topic policies allow cross-account publishing and subscribing - Fan-out patterns distribute events to multiple endpoints - Supports multiple protocols including Lambda, SQS, HTTP, and email
AWS Config For compliance and configuration event aggregation: - Aggregators collect Config data from multiple accounts and regions - Organization-wide rules evaluate compliance across all member accounts - Notifications via SNS for compliance state changes
Amazon CloudWatch Cross-account observability features: - Cross-account dashboards aggregate metrics - Cross-account alarms monitor resources in other accounts - Log subscription filters route logs across accounts
Common Architecture Patterns
Hub-and-Spoke Pattern A central management account receives events from all spoke accounts. The hub account contains: - Central EventBridge event bus - Aggregated SNS topics - Processing Lambda functions - Security and compliance dashboards
Event Bus Forwarding Member accounts configure EventBridge rules to forward specific events to a central event bus. This requires: - Resource-based policy on the central event bus allowing PutEvents from member accounts - Rules in member accounts with the central event bus as a target - IAM roles for cross-account event delivery
Organization-Wide Event Collection Using AWS Organizations integration: - EventBridge rules can specify organization ID in resource policies - CloudTrail organization trails capture API activity across all accounts - Config aggregators automatically include organization accounts
How to Configure Cross-Account EventBridge
1. In the central account, create an event bus and attach a resource policy:
Resource Policy Example:{ "Version": "2012-10-17", "Statement": [{ "Sid": "AllowOrgAccounts", "Effect": "Allow", "Principal": "*", "Action": "events:PutEvents", "Resource": "arn:aws:events:region:central-account:event-bus/central-bus", "Condition": { "StringEquals": { "aws:PrincipalOrgID": "o-xxxxxxxxxx" }}}] } 2. In member accounts, create rules that target the central event bus 3. Configure IAM roles for cross-account event delivery 4. Set up processing rules in the central account
Cross-Account SNS Configuration
For SNS cross-account notifications: - Add a topic policy allowing cross-account publish or subscribe actions - Use AWS Organizations conditions to allow all organization accounts - Consider encryption with KMS and cross-account key policies
Security Considerations
- Apply least privilege to cross-account permissions - Use organization ID conditions rather than listing individual account IDs - Encrypt events in transit and at rest using KMS - Implement VPC endpoints for private connectivity - Enable CloudTrail logging for audit trails
Exam Tips: Answering Questions on Multi-Account Event Notifications
Identify the Event Source Type - Security findings → Security Hub with delegated administrator - Configuration changes → AWS Config aggregators - Custom application events → EventBridge cross-account event buses - API activity → CloudTrail organization trails
Choose the Right Service Based on Requirements - Real-time event processing → EventBridge - Simple notifications and fan-out → SNS - Compliance monitoring → Config with aggregators - Security posture management → Security Hub
Watch for Keywords - "Centralized monitoring" suggests hub-and-spoke with EventBridge - "Organization-wide" indicates AWS Organizations integration - "Compliance across accounts" points to Config aggregators - "Security findings aggregation" means Security Hub
Resource Policy vs IAM Policy - Cross-account access to EventBridge event buses requires resource-based policies - SNS topics need topic policies for cross-account access - IAM roles are needed for the sending account to assume permissions
Scalability Considerations - EventBridge scales better than polling-based solutions - Organization-level policies are more maintainable than per-account configurations - Delegated administrator accounts reduce management overhead
Common Exam Scenarios - Aggregating CloudTrail logs from all accounts → Organization trail to central S3 bucket - Centralizing security alerts → Security Hub with cross-account finding aggregation - Triggering automated remediation across accounts → EventBridge forwarding to central Lambda - Monitoring compliance organization-wide → Config aggregators with SNS notifications
Remember Key Limitations - EventBridge cross-region event routing requires explicit rules - SNS cross-region delivery needs separate topic in each region - Config aggregators have limits on number of accounts and regions
Best Practice Indicators in Questions - Solutions using AWS Organizations integration are preferred over manual account-by-account setup - Managed services like Security Hub aggregation are favored over custom implementations - Event-driven architectures are preferred over polling mechanisms - Solutions that minimize operational overhead while maintaining security are optimal