Single point of failure

As explained in Amazon Web Services in Action, Third Edition: An in-depth guide to AWS

A single point of failure is a component whose failure can cause a system or service to fail because no redundant component can take over.

A single point of failure (SPOF) is a component whose failure can bring down a system because no redundant component can take over. A system with a SPOF may serve no requests when that component fails. section 16.0

Avoid SPOFs by adding redundancy and decoupling components. Multiple application instances can continue serving requests when one fails, while a load balancer or message queue separates clients from those instances. section 16.0 section 16.1.1

Common AWS architecture choices include:

• Replace one EC2 instance with multiple instances, preferably across availability zones, so one instance or zone can fail without stopping service. section 16.1 section 16.4
• Use an Auto Scaling group with redundant EC2 instances and an Elastic Load Balancer to distribute incoming requests. section 16.4 section 16.1.2
• Use an SQS queue for asynchronous decoupling; ELB and SQS are fault tolerant by default even when shown only once in an architecture. section 16.1.2

Single-node Redis

An ElastiCache for Redis single-node cluster contains one node, cannot shard or provide high availability, and therefore adds a SPOF. Backups and restoration provide recovery options but do not remove the single-node dependency. section 11.2.2

Figure 16.2 Redundancy eliminates single points of failure and makes the system more stable.

Compare a single production path with redundant paths to see how redundancy prevents one failed component from stopping the entire system. section 16.1.1

How Amazon Web Services in Action, Third Edition: An in-depth guide to AWS covers it

How deep it goes

Explains failure effects, redundancy, and decoupling through EC2, Redis, load-balancer, and queue examples, without detailing implementation commands.

Examples

Uses single-node Redis, one EC2 instance, redundant production lines, multi-zone EC2 deployments, ELB, and SQS as concrete examples.

What it assumes

Assumes basic awareness of system components while teaching fault tolerance, redundancy, and decoupling through production and EC2 examples.

What you can do after

Designs architectures that remove SPOFs by combining redundant EC2 instances with load balancers, queues, availability zones, or fault-tolerant services.

How it connects

Connects single points of failure with fault tolerance, redundancy, decoupling, availability zones, load balancers, message queues, and Auto Scaling groups.

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Also explained in

• 

  liveBookmanning.com
  Think Like a CTOA single point of failure is a component whose failure can disrupt or halt a system because no adequate redundant alternative is available.
• 

  liveBookmanning.com
  Think Like a Software Engineering ManagerA single point of failure is a person, component, or dependency whose inability to function can prevent a system or process from operating successfully.
• 

  liveBookmanning.com
  Real-World CryptographyA single point of failure is a component or condition whose compromise or failure can disable or undermine an entire system.

Compare how 4 books explain single point of failure →

Related concepts

• redundancyaddressed by · Redundancy is the presence of duplicate or overlapping information, components, or resources, whether intentional or unnecessary.
• distributed systemaddressed by · A distributed system is a computing system whose components run across multiple networked processes or machines and coordinate through communication.
• Amazon Elastic Compute Cloudincludes · Amazon Elastic Compute Cloud (EC2) is an Amazon Web Services service that provides resizable virtual computing capacity through configurable virtual machine instances.
• clusteringaddressed by · Clustering is the technique of grouping data items according to similarity or shared characteristics.

This explainer was generated by Manning's knowledge graph from the text of Amazon Web Services in Action, Third Edition: An in-depth guide to AWS. The section links point to the parts of the book it draws on.