Making All Responses Idempotent A system is said to be idempotent if a given request made multiple times leads to the same result as that same request made exactly once. Idempotency facilitates failure handling since, upon a request failure, you can retry the request without taking much care whether it is retried once or multiple […]

Designing Interactions in a Distributed System to Prevent Failures One of the aspects that influences a distributed system most is communication between the different elements of the system. There is already quite a number of things that can go wrong in a simple client-server scenario; that number becomes simply mind-boggling in a large microservices architecture. […]

Designing for Failure When designing a workload’s architecture for a distributed environment such as the AWS cloud, you must design first to try and prevent failures, and second to handle failures. As previously mentioned in the design principles, your workload design must be able to cope with variations in the workload’s demand, detect failures, and […]

Ensuring IPv4 Subnet Allocation Accounts for Expansion and Availability You need to plan for enough IPv4 addresses to be available, not only today but also for future use as well. That may sound obvious but the number of IP addresses needed can be easily overlooked. In the count, you must include all the resources that […]

Provisioning Redundant Connectivity between Your AWS and On-Premises Environments When connecting your on-premises environment to your AWS environment, it is highly recommended to make those connections redundant to sustain the failure of any single one of them. Large organizations are likely to use some form of private connectivity for security purposes; you will then end […]

Using Highly Available Network Connectivity for Your Public Endpoints Starting from the assumption that your internet-facing endpoints must be highly available, you have to make sure that whichever component you lay on their path is also highly available, whether it is a DNS service, a content delivery network (CDN), a load-balancing capability, or a gateway […]

Foundational Requirements First things first, it’s essential to consider your foundations, that is, your AWS environment, which must be able to accommodate the workload requirements. Two elements in particular must be tackled as they could impact the reliability of any workload: resource constraints and network topology. Resource Constraints Resource constraints can be further split into […]

Principle 2 – Test Recovery Procedures Having automated recovery procedures is good, but making sure they work is better. If you’re new to the cloud, you may be used (in your on-premises environment) to testing your workloads and making sure they work in “normal” conditions, but you may be less used to testing recovery procedures […]

Summary This chapter has covered quite a lot of ground in terms of designing secure solutions on AWS. You learned how to leverage IAM and identity federation in your solution to provide granular access control. You then looked at the best practices to protect your infrastructure resources—using tools such as AWS WAF, AWS Shield, and […]

Responding to Incidents Detecting incidents is one thing, but being able to respond to them in a timely manner is even more important. Assume that you have put in place the necessary mechanisms to detect and prioritize incidents. What is next? Next, you want the ability to remediate these incidents. There can be, however, several […]