The Unfiltered Guide: Critical AWS Migration Mistakes and How to Avoid Them
Critical AWS Migration Mistakes
Migrating data to AWS presents challenges that are more complex than many might imagine. The most common mistakes in this process can arise from the most basic aspects, such as converting files from EBCDIC to ASCII format—a common issue in mainframe computing environments. However, it can also involve high-impact errors, such as the lack of an effective methodology. For example the Big Bang Approach: attempting to migrate everything at once can be risky and lead to significant problems.
In this guide, we will examine the most critical mistakes that occur during AWS migrations and, more importantly, provide you with strategies to effectively avoid them. From the initial planning phase to the post-migration phase, we will cover every essential aspect to ensure a successful migration.
Mistakes in the Planning Phase
The most costly mistakes in AWS migrations often occur during the initial planning phase. A detailed portfolio analysis is essential to make well-informed technical and business decisions.
It is crucial to include the Technical Lead (TL) as part of the analysis and planning process. This analysis should incorporate the design of the current architecture, data flow diagrams, as well as the interoperability of services and their dependencies.
Additionally, it is vital to identify which services are in use and the type of environment you have. All this information must be gathered beforehand to address the technical aspects and properly size the future architecture (To Be).
Underestimating Required Resources
Inadequate assessment of required resources is one of the main obstacles. AWS Application Discovery Service (ADS) is essential for identifying critical details such as host names, IP and MAC addresses, as well as resource allocation and utilization. However, many organizations fail to consider that large migrations may require between 10 and 30 applications for the initial phase.
Lack of Dependency Analysis
Incomplete dependency analysis can cause significant delays. ADS monitors incoming and outgoing network activity to identify interconnections between servers. Therefore, it is crucial to understand how the infrastructure interacts with other systems, especially in environments where applications have been hosted on-premises for decades.
Absence of a Contingency Plan
The lack of a solid contingency plan can be catastrophic. To minimize risks, it is essential to develop:
- Mitigation strategies for unexpected disruptions
- Synchronization plans to maintain data consistency
- Adjustment protocols for network configurations
Moreover, organizations often underestimate the complexity of dependencies between applications, data and infrastructure. The key is to maintain flexibility and develop contingency plans that allow the program to continue moving forward, even when unexpected challenges arise.
Migrations can stall when prerequisites are not met, affecting not only the current migration wave but also delaying all future migrations. For this reason, it is essential to conduct thorough preliminary assessments to identify potential problem scenarios.
Failures During Technical Preparation
Technical preparation is a critical phase where mistakes can compromise the entire migration. During this stage, incorrect configurations and undetected compatibility issues can lead to significant delays and additional costs.
Incorrect Security Configuration
A highly relevant aspect of AWS migration is the proper selection of services, especially when deciding between serverless and dedicated options. This choice can have a significant impact on costs and maintenance. Below are the key differences between selecting serverless services versus dedicated services:
- Costs:
- Serverless: You only pay for actual resource usage, which can lead to substantial savings, especially for workloads with variable or intermittent usage patterns.
- Dedicated: You pay for provisioned resources, regardless of actual utilization. This can result in higher costs, especially if resources are underutilized.
- Scalability:
- Serverless: Offers automatic scaling, allowing resources to adjust dynamically based on demand. It is ideal for applications with unpredictable workload fluctuations.
- Dedicated: Requires proactive management and planning to scale resources, which can be less efficient and slower to respond to sudden demand spikes.
- Maintenance:
- Serverless: You don’t have to worry about server management, including updates, security patches, and general maintenance. This allows your team to focus on application development and improvement.
- Dedicated: You are responsible for server maintenance and management, increasing operational overhead and demanding more time and resources from your team.
- Flexibility:
- Serverless: Ideal for building microservices and event-driven applications, offering greater flexibility in design and architecture.
- Dedicated: Provides greater control over infrastructure, necessary for applications with specific hardware or configuration requirements.
- Response Time:
- Serverless: May experience initial latency (known as “cold start”) when serverless functions are activated after a period of inactivity.
- Dedicated: Generally offers more consistent response times since resources are always available.
- Security:
- Serverless: Infrastructure-level security is managed by the cloud service provider, reducing user responsibility.
- Dedicated: Requires you to manage and secure the infrastructure, which can be more complex and demanding.
Inadequate configuration of security groups and IAM roles is one of the main technical obstacles in migration. The most common mistakes include overly restrictive permissions or, conversely, overly permissive ones, which can compromise security. Additionally, the lack of proper AWS WAF configuration can expose resources to threats during migration.
A critical aspect is the management of TLS certificates and the implementation of subordinate certificate authorities, especially in accounts requiring private certificates. Therefore, it is essential to establish robust security protocols from the outset.
Undetected Compatibility Issues
Compatibility challenges often manifest at multiple levels. Custom and commercial applications require thorough compatibility verification with AWS Directory Service. However, many organizations skip this crucial step.
The most common incompatibilities arise when:
- Applications require domain administrator permissions
- There is limited access to privileged containers
- Schema changes are required during installation
Mistakes in AWS Service Selection
Incorrect selection of AWS services can lead to performance issues and unnecessary costs. For example, EC2 vCPU quota limitations can cause jobs to fail before the application even runs.
When selecting EC2 instances, which are the most common, the following aspects should be evaluated:
Negative Impacts of Choosing the Wrong EC2 Instance Type
- High Costs:
- Overprovisioning: Selecting a more powerful instance than necessary can result in paying for unused resources, unnecessarily increasing operational costs.
- Underprovisioning: Choosing an insufficient instance can lead to a need for rapid scaling, which can also increase costs.
- Poor Performance:
- Underprovisioning: Instances with insufficient resources can cause bottlenecks, slow response times, and degraded application performance, affecting user experience.
- Incompatibility: Some applications may require specific instance types (e.g., GPU or high-performance storage) and may not perform optimally on generic instances.
Practical Examples:
- T2/T3 Instances (Burstable): Ideal for workloads that do not require constant CPU usage, such as web servers. Using these instances for CPU-intensive applications can result in inadequate performance.
- R5 Instances (Memory Optimized): Designed for applications requiring large amounts of memory. Using them for applications with low memory usage can generate unnecessary costs.
In summary, selecting the correct EC2 instance type is crucial for optimizing costs, ensuring good performance, enabling scalability, and maintaining proper management and security. If you are unsure about which instance type to choose, it is advisable to conduct tests and monitor performance before making a decision.
A common mistake is not verifying if instances are being correctly requested by AWS Batch or if the computing environment scales as expected. Similarly, an insufficient number of IP addresses in the VPC and subnets can significantly limit the creation of necessary instances.
Proper service selection should consider factors such as scalability, service limits, and compatibility with existing infrastructure. Therefore, it is essential to conduct a detailed assessment of the specific requirements of each component before proceeding with the migration.
Problems During Migration Execution
During the execution of an AWS migration, technical challenges materialize into concrete issues that require immediate attention. AWS Migration Hub becomes a critical tool by providing a centralized location to monitor migration progress.
Migration Stalled Due to Lack of Tracking
Inadequate tracking represents one of the greatest risks in migration projects, as they can stall when:
- Data replication stops due to connectivity issues
- Source servers disconnect from the service
- Replication duration exceeds established thresholds
AWS Migration Hub provides key metrics on individual applications that facilitate tracking the process, regardless of the tools used for migration.
Data Transfer Errors
AWS Database Migration Service (AWS DMS) facilitates database migration while maintaining the original source’s operability. However, frequent complications arise, such as:
- Incorrect resource allocation to the replication instance, causing slow migration tasks. Therefore, it is essential to monitor CPU, memory, and IOPS usage of the replication instance to ensure sufficient resources.
- Inadequate table statistics affect the accuracy of progress estimates. To improve performance, it is recommended to temporarily disable automatic backups and logging in the target database.
Inadequate Interruption Management
Complexity increases when the transition period shortens, especially for business-critical applications. To minimize the impact of interruptions, it is essential to:
- Lock the source environment before starting the transition to ensure no new transactions occur during the process. However, if the application receives new transactions after a successful transition, reverting may require restoring data from the cloud environment to the on-premises environment.
AWS DMS offers the option to configure a recovery database that replicates data to a new local database, facilitating reversion in case of issues. This strategy is especially valuable when the original database becomes obsolete after migration.
Common Post-Migration Mistakes
After completing the migration to AWS, many organizations face critical challenges that can compromise the long-term success of their cloud operations. These post-migration challenges require immediate attention and specific strategies for effective management.
Insufficient Monitoring
Inadequate monitoring after migration poses a significant risk to operational stability. AWS CloudWatch becomes a critical tool for monitoring resources and applications. However, many organizations fail to implement centralized monitoring of logs, AWS services, and S3 buckets.
Therefore, it is essential to establish monitoring dashboards that include:
- Key SLA metrics
- Service Level Indicators (SLIs)
- Traffic patterns and hotspots
Poor Cost Optimization
Inadequate cost management post-migration can result in significant unnecessary expenses. Organizations often migrate without establishing clear KPIs on expected costs. Additionally, overprovisioning instances is one of the most costly mistakes, especially when migrating servers sized for three years of service.
Effective optimization requires continuous evaluation using Amazon CloudWatch to analyze instance utilization. However, many companies fail to resize AWS instances after migration, resulting in costs up to five times higher than initial estimates.
Lack of Updated Documentation
Outdated documentation creates significant challenges in post-migration management. Institutional knowledge about legacy systems can be limited by outdated documentation or staff changes. Therefore, it is essential to maintain updated records of:
- Application dependencies, especially when there are incoming and outgoing connections on migrated servers. However, many organizations fail to adequately document dependency chains, which can lead to service degradation or outages.
Implementing post-migration warranty periods, typically between one day and one week, allows for the identification and resolution of emerging issues. However, applications with quarterly batch programs may require longer periods to fully validate their functionality.
Correction and Recovery Strategies
When migration processes encounter obstacles, correction and recovery strategies become crucial elements for maintaining operational continuity. AWS offers a robust set of tools and procedures to effectively manage these scenarios.
IaC (Infrastructure as Code) and DRP (Disaster Recovery Plan) Procedures
Rollback procedures in AWS are executed by redeploying a previous version of the application as if it were a new deployment. These rolled-back deployments are technically new deployments with unique identifiers, rather than restored versions of a previous deployment.
AWS CodeDeploy allows for the configuration of automatic rollbacks when a deployment fails or a specific monitoring threshold is reached. Additionally, the rollback process includes the removal of previously installed files, verifying the cleanup file on each participating instance.
Blue/Green Deployment Strategy in AWS CodeDeploy
The blue/green deployment strategy is a software release technique aimed at minimizing downtime and reducing risks associated with deploying new versions of an application. Here’s how it works:
- Two Identical Environments: Two production environments are set up, one called “blue” and the other “green.” The blue environment is the one currently in operation, while the green environment is a copy of the blue environment but with the new version of the application.
- Testing in the Green Environment: The green environment is thoroughly tested to ensure the new application version works correctly. This includes functional, performance, and compatibility testing.
- Traffic Redirection: Once the green environment passes all tests, production traffic is redirected to the green environment in a controlled manner to ensure a smooth transition.
- Deployment in the Blue Environment: The blue environment is used to deploy the next version of the application during the next deployment cycle.
- Rollback if Necessary: If issues are found in the green environment, traffic redirection can be reverted to the blue environment, minimizing user impact.
AWS CodeDeploy facilitates this strategy by managing revisions and traffic weights, enabling safer and more efficient deployments.
Specialized AWS Tools for Problem Diagnosis and Resolution
AWS offers a variety of specialized tools for problem diagnosis and resolution. Among them, AWS CloudTrail stands out as a centralized solution for governance, compliance, and operational auditing. This tool allows tracking of user activities and API usage, facilitating the identification of configuration errors.
AWS Systems Manager provides capabilities for obtaining detailed insights into operations and taking corrective actions. On the other hand, AWS Trusted Advisor optimizes performance and security, while the AWS Well-Architected Tool allows for reviewing and improving migrated workloads.
AWS Audit Manager is the service designed for system auditing. This service helps continuously audit AWS usage, simplifying risk management and compliance with industry regulations and standards. AWS Audit Manager automates evidence collection, facilitating the evaluation of the effectiveness of your policies, procedures, and activities (also known as controls).
Features of AWS Audit Manager:
- Automatic Evidence Collection: Automatically collects data from your AWS accounts and transforms it into auditable evidence.
- Preconfigured Frameworks: Offers preconfigured frameworks that structure and automate evaluations to comply with specific compliance standards.
- Continuous Monitoring: Allows monitoring of active evaluations and quickly identifies non-compliant evidence that needs remediation.
- Multi-Environment Compatibility: You can upload and manage evidence from hybrid or multi-cloud environments.
Escalation Protocols
Escalation protocols in AWS require clearly defined routes to facilitate timely and effective actions. AWS Systems Manager Incident Manager allows for the establishment of structured escalation plans that include:
- Specific durations for each escalation stage
- Escalation channels composed of unique contacts or on-call programs
- Options to stop plan progression when participation is acknowledged
To implement effective protocols, it is essential to establish clear escalation indications and detail specific processes. Additionally, pre-approval of actions accelerates decision-making and reduces mean time to resolution.
Escalation plans use stages where each lasts a defined number of minutes. During these stages, the system engages each channel using its defined participation plan, allowing for an organized and efficient response to incidents.
Conclusion
Migrating to AWS represents a significant challenge that requires meticulous attention at every phase of the process. After analyzing the most frequent mistakes, we can affirm that success depends primarily on thorough planning and careful execution.
Undoubtedly, proper technical preparation makes the difference between a successful migration and a problematic one. Security configurations, system compatibility, and appropriate AWS service selection constitute fundamental elements that must be considered from the start.
The execution phase has shown us that constant tracking and effective interruption management are crucial. Certainly, tools like AWS Migration Hub and Database Migration Service facilitate this process, although we must maintain clear monitoring and control protocols.
The post-migration period demands equal attention. Cost optimization, updated documentation, and continuous monitoring ensure that our cloud investment generates the expected results. Correction and recovery strategies provide solid backup in case of setbacks.
Finally, let’s remember that each migration is unique and presents its own challenges. However, with a clear understanding of common mistakes and strategies to avoid them, we can ensure a smoother and more successful transition to AWS.
FAQs
What are the most common mistakes when migrating to AWS?
Some frequent mistakes include not having clear objectives, replacing physical servers with EC2 instances without leveraging native cloud services, incorrectly configuring security, and underestimating required resources. It is important to have a well-defined strategy and leverage AWS’s unique capabilities.
How can I optimize costs after migrating to AWS?
To optimize costs, closely monitor resource usage with tools like CloudWatch, resize instances as needed, leverage reserved instances and savings plans, and consider turning off development environments when not in use. Continuous optimization is key to controlling expenses.
What should I consider regarding security when migrating to AWS?
It is crucial to correctly configure security groups and IAM roles, implement proper encryption, use AWS WAF to protect web applications, and keep security policies updated. It is also important to train staff on AWS cloud security best practices.
How can I ensure a successful database migration to AWS?
Use AWS Database Migration Service to facilitate migration while keeping the original database operational. Ensure proper resource allocation to the replication instance, update table statistics, and consider temporarily disabling automatic backups in the target database to improve performance.
What recovery strategies should I implement after migration?
Implement rollback procedures using AWS CodeDeploy for automatic rollbacks, leverage diagnostic tools like AWS CloudTrail and Systems Manager, and establish clear escalation protocols with AWS Incident Manager. Ensure you have contingency plans and updated documentation to effectively handle any post-migration issues