Applications in the Cloud are reliable, and in some cases even cheaper than on-premises, but we all have made a lot of mistakes when started with AWS.

Cost Optimization

First and one of the most important tips to keep in mind:

• Monitor your AWS costs by setting billing alerts & automate everything

CloudFormation template

---AWSTemplateFormatVersion:"2010-09-09"Description:"Simplebudgetexample"Parameters:Email:Type:StringDefault:email@example.comDescription:Please enter the email address to which budget notifications should be addressed.Resources:BasicBudget:Type:"AWS::Budgets::Budget"Properties:Budget:BudgetLimit:Amount:10Unit:USDTimeUnit:MONTHLYBudgetType:COSTNotificationsWithSubscribers:-Notification:NotificationType:ACTUALComparisonOperator:GREATER_THANThreshold:99Subscribers:-SubscriptionType:EMAILAddress:!RefEmail-Notification:NotificationType:ACTUALComparisonOperator:GREATER_THANThreshold:80Subscribers:-SubscriptionType:EMAILAddress:!RefEmailOutputs:BudgetId:Value:!RefBasicBudget

• Tag everything

Performance Efficiency

• Use Serverless Architectures as much as possible
• Store no application state
• Log useful information and enable traceability

Reliability

• Scale-out is better in most of the cases

Security

• Create an IAM user for your AWS account.
• Enable MFA in all your AWS users
• Grant roles to EC2, applications should not have AIM accounts
• Assign privileges to groups and not directly to the users

Operational Excellence

• Leverage Infrastructure as Code: Terraform, CDK or even CloudFormation
• Make things easy to rollback