Migration & Modernization

Unlock Cloud Savings, A Rehost Migration Playbook (Part 4: Migrate – Realizing Planned Savings)

This blog post is the fourth in a four-part series series to provide you a step-by-step guide on how to optimize costs throughout an AWS Rehost migration, specifically:

    1. Exploring your cost components and on-premises environment.
    2. Building an accurate business case during the assess phase.
    3. Understanding and controlling cloud spend during the mobilize phase.
    4. Optimizing costs to realize the planned financial savings during the migrate phase.

Rehost Migration Cost Activity Overview by Phase, highlighting Migrate, Realize planned savings.

Figure 1. Rehost Migration Cost Activity Overview by Phase

1. Cost Optimization on AWS

We use specific AWS services and tools throughout the Rehost migrations to optimize costs. These AWS services provide recommendations for optimizing HAQM EC2 instance costs, storage costs, and overall application run cost. Cost savings may increase because the migration and initial optimization used application performance metrics from the on-premises data center (CPU, memory, disk I/O, and network). Post-migration cost optimization requires analyzing utilization metrics, which vary depending on the instance type and size.

1.1. AWS Billing and Cost Management Home

AWS Billing and Cost Management provides key services to optimize costs throughout your Rehost migration. If you are using AWS Organizations with a management account to centrally govern your AWS environment, configure the member accounts to access these services in accordance with your organization’s needs and access policies. These services apply to teams beyond your designated cost management stakeholders.

The AWS Billing and Cost Management console provides summarized information enabling the account owner to dive deeper into a specific category. The landing page has default widgets, which provides a quick view of the current forecast of current vs cost over the last few months. The info tab provides a detailed summary and explanation of what information the widget provides to the account owner.

The default widgets within the AWS Billing and Cost Management console are:

  • Cost Summary – The current trends compared to your spending in the last month. The costs presented here do not include any credits and discounts.
  • Cost Monitor – Your cost and budgets and any cost anomalies detected by AWS. The Cost Anomalies status within Cost Monitor is based on the setup done within Cost monitors, which is under Cost Anomaly Detection tab.
  • Cost breakdown – A breakdown of the last 6 months to help understand the cost trends and drivers. Group costs by metrics such as AWS service, member account, region, cost allocation tag, and cost category.
  • Recommended Actions – Guidance for the AWS account owner to follow AWS cloud financial management best practices and optimize costs based on the recommendations provided.
  • Savings Opportunities – Recommendations from the Cost Optimization Hub on various categories, like right sizing, different instance types and recommendation for deletion of unused resources within an account.

1.2. AWS Cost Explorer

The cost breakdown widget opens into AWS Cost Explorer, allowing the account owners and designated cost management stakeholders to visualize, analyze, and manage the costs in AWS. AWS Cost Explorer provides high-level and detailed insights into the spending trends. Filtering and forecasting allow you to pinpoint cost drivers and anomalies. Reports can be customized to meet your requirements for a specific date range at varied granularity (hourly, daily, monthly) and grouping by service. You can store these reports in the library for future access.

1.3. AWS Cost Optimization Hub

AWS Cost Optimization Hub provides an overview of the cost optimization opportunities for your migrated EC2 instances. In Figure 2, we see after the Rehost migration, there is a recommendation of migrating to Graviton instances to achieve additional savings. Also based on the CPU and memory utilization metrics, the cost optimization hub will recommend right sizing of the instances and deletion of resources that are idle.

Cost Optimization Hub and Recommendations

Figure 2: Cost Optimization Hub and Recommendations

By leveraging the Cost Optimization Hub, designated cost management teams can more effectively identify, prioritize, and implement cost-saving measures across their AWS environment, leading to improved cloud financial management, resource optimization, and cost savings in addition to what was achieved during the migration to AWS.

1.4. AWS Compute Optimizer

AWS Compute Optimizer helps reduce EC2 instance costs through right-sizing recommendations. It provides savings overview, performance enhancement and optimization recommendations by region for the following resources:

  • HAQM EC2
  • HAQM EC2 Auto scaling groups
  • HAQM EBS
  • AWS Lambda functions
  • HAQM ECS on AWS Fargate
  • Commercial software licenses
  • HAQM RDS DB instances and storage

By opting in to the Compute Optimizer, you allow it to evaluate your AWS resources by reviewing their specifications and utilization patterns recorded by HAQM CloudWatch over the last 14 days. This assessment involves metrics such as CPU usage, network transfer, disk operations, and current instance utilization.

2. Conclusion

Establish dedicated ownership and implement systematic cost monitoring processes using AWS Cost Explorer, AWS Budgets, and AWS Cost and Usage Reports. These tools, combined with AWS Cost Optimization Hub and AWS Compute Optimizer, provide actionable recommendations for EC2 instances, storage, and application optimizations. Regular analysis of resource utilization patterns and implementation of sizing recommendations ensures sustained cost efficiency beyond initial migration savings, creating a foundation for continuous cost optimization.

In this blog post we concluded our Rehost migration cost optimization journey in the migrate phase by: Reviewing the services available in 1.1 AWS Billing and Cost Management Home; Using 1.2 AWS Cost Explorer to visualize and analyze costs; And reviewing 1.3 AWS Cost Optimization Hub and 1.4 AWS Compute Optimizer for prescriptive recommendations for cost optimization and right-sizing opportunities.

Blog Series

Direct links to each of the blog posts in this series are as follows:

Additional Resources

Contact an AWS migration specialist to discuss how we can help your organization.

Ready to migrate and optimize your costs? Here are some additional resources:

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