Reliability Pillar

The reliability pillar focuses on ensuring a workload performs its intended function correctly and consistently when it's expected to. This includes the ability to operate and test the workload through its total lifecycle.

The Reliability pillar includes the ability to support development and run workloads effectively, gain insight into their operations, and to continuously improve supporting processes and procedures to deliver business value.

Reliability Questions

REL01: How do you manage service quotas and constraints?

• View all REL01 best practices
• REL01-BP01: Aware of service quotas and constraints
• REL01-BP02: Manage service quotas across accounts and regions
• REL01-BP03: Accommodate fixed service quotas and constraints through architecture
• REL01-BP04: Monitor and manage quotas
• REL01-BP05: Automate quota management
• REL01-BP06: Ensure that a sufficient gap exists between the current quotas and the maximum usage to accommodate failover

REL02: How do you plan your network topology?

• View all REL02 best practices
• REL02-BP01: Use highly available network connectivity for your workload public endpoints
• REL02-BP02: Provision redundant connectivity between private networks in the cloud and on-premises environments
• REL02-BP03: Ensure IP subnet allocation accounts for expansion and availability
• REL02-BP04: Prefer hub-and-spoke topologies over many-to-many mesh
• REL02-BP05: Enforce non-overlapping private IP address ranges in all private address spaces where they are connected

REL03: How do you design your workload service architecture?

• View all REL03 best practices
• REL03-BP01: Choose how to segment your workload
• REL03-BP02: Build services focused on specific business domains and functionality
• REL03-BP03: Provide service contracts per API

REL04: How do you design interactions in a distributed system to prevent failures?

• View all REL04 best practices
• REL04-BP01: Identify the kind of distributed systems you depend on
• REL04-BP02: Implement loosely coupled dependencies
• REL04-BP03: Do constant work
• REL04-BP04: Make mutating operations idempotent

REL05: How do you design interactions in a distributed system to mitigate or withstand failures?

• View all REL05 best practices
• REL05-BP01: Implement graceful degradation to transform applicable hard dependencies into soft dependencies
• REL05-BP02: Throttle requests
• REL05-BP03: Control and limit retry calls
• REL05-BP04: Fail fast and limit queues
• REL05-BP05: Set client timeouts
• REL05-BP06: Make systems stateless where possible
• REL05-BP07: Implement emergency levers

REL06: How do you monitor workload resources?

• View all REL06 best practices
• REL06-BP01: Monitor all components for the workload (Generation)
• REL06-BP02: Define and calculate metrics (Aggregation)
• REL06-BP03: Send notifications (Real-time processing and alarming)
• REL06-BP04: Automate responses (Real-time processing and alarming)
• REL06-BP05: Create dashboards
• REL06-BP06: Review metrics at regular intervals
• REL06-BP07: Monitor end-to-end tracing of requests through your system

REL07: How do you design your workload to adapt to changes in demand?

• View all REL07 best practices
• REL07-BP01: Use auto scaling or on-demand resources
• REL07-BP02: Obtain resources upon detection of impairment to a workload
• REL07-BP03: Obtain resources upon detection that more resources are needed for a workload
• REL07-BP04: Load test your workload

REL08: How do you implement change?

• View all REL08 best practices
• REL08-BP01: Use runbooks for standard activities such as deployment
• REL08-BP02: Integrate functional testing as part of your deployment
• REL08-BP03: Integrate resiliency testing as part of your deployment
• REL08-BP04: Deploy using immutable infrastructure
• REL08-BP05: Deploy changes with automation

REL09: How do you back up data?

• View all REL09 best practices
• REL09-BP01: Identify and back up all data that needs to be backed up, or reproduce the data from sources
• REL09-BP02: Secure and encrypt backups
• REL09-BP03: Perform data backup automatically
• REL09-BP04: Perform periodic recovery of the data to verify backup integrity and processes

REL10: How do you use fault isolation to protect your workload?

• View all REL10 best practices
• REL10-BP01: Deploy the workload to multiple locations
• REL10-BP02: Select the appropriate locations for your multi-location deployment
• REL10-BP03: Automate recovery for components constrained to a single location

REL11: How do you design your workload to withstand component failures?

• View all REL11 best practices
• REL11-BP01: Monitor all components of the workload to detect failures
• REL11-BP02: Fail over to healthy resources
• REL11-BP03: Automate healing on all layers
• REL11-BP04: Rely on the data plane and not the control plane during recovery
• REL11-BP05: Use static stability to prevent bimodal behavior
• REL11-BP06: Send notifications when events impact availability
• REL11-BP07: Architect your product to meet availability targets and uptime service level agreements (SLAs)

REL12: How do you test reliability?

• View all REL12 best practices
• REL12-BP01: Use playbooks to investigate failures
• REL12-BP02: Perform post-incident analysis
• REL12-BP03: Test functional requirements
• REL12-BP04: Test scaling and performance requirements
• REL12-BP05: Test resiliency using chaos engineering

REL13: How do you plan for disaster recovery?

• View all REL13 best practices
• REL13-BP01: Define recovery objectives for downtime and data loss
• REL13-BP02: Use defined recovery strategies to meet the recovery objectives
• REL13-BP03: Test disaster recovery implementation to validate the implementation
• REL13-BP04: Manage configuration drift at the DR site or region
• REL13-BP05: Automate recovery

AWS Services for Reliability

Amazon CloudWatch

Monitors your AWS resources and the applications you run on AWS in real time.

AWS Auto Scaling

Monitors your applications and automatically adjusts capacity to maintain steady, predictable performance.

Amazon RDS

Makes it easy to set up, operate, and scale a relational database in the cloud with high availability.

AWS Elastic Disaster Recovery

Minimizes downtime and data loss with fast, reliable recovery of on-premises and cloud-based applications.

AWS Backup

Centrally manages and automates backups across AWS services.

Elastic Load Balancing

Automatically distributes incoming application traffic across multiple targets.

Amazon Route 53

Provides highly available and scalable cloud Domain Name System (DNS) web service.

Related Resources

• AWS Well-Architected Framework - Reliability Pillar
• Reliability on AWS
• AWS Architecture Blog
• AWS Disaster Recovery

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Table of contents

• REL01 - How do you manage service quotas and constraints?
• REL02 - How do you plan your network topology?
• REL03 - How do you design your workload service architecture?
• REL04 - How do you design interactions in a distributed system to prevent failures?
• REL05 - How do you design interactions in a distributed system to mitigate or withstand failures?
• REL06 - How do you monitor workload resources?
• REL07 - How do you design your workload to adapt to changes in demand?
• REL08 - How do you implement change?
• REL09 - How do you back up data?
• REL10 - How do you use fault isolation to protect your workload?
• REL11 - How do you design your workload to withstand component failures?
• REL12 - How do you test reliability?
• REL13 - How do you plan for disaster recovery?