Serverless Computing

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Serverless is a software architecture that runs functions within virtualized runtime containers in a cloud rather than on dedicated server instances.

• aka Function as a Service
• modern design pattern for service delivery
• provides a scalable, cost-effective, and easy-to-manage infrastructure for event-driven and data-processing tasks

How it Works

• all the architecture is hosted within a cloud
  • but unlike “traditional” virtual private cloud (VPC) offerings,
    • services such as authentication, web applications, and communications aren’t developed and managed as applications running on VM instances within the cloud
    • Instead, the applications are developed as functions and microservices
      • each interacting with other functions to facilitate client requests
    • When the client requires some operation to be processed, the cloud spins up a container to run the code, performs the processing, and then destroys the container
• Billing is based on execution time rather than hourly charges
• eliminate the need to manage physical or virtual server instances
  •  little to no management effort for:
    • software and patches
    • administration privileges
    • or file system security monitoring
  • allow focus on developing and deploying applications
• no requirement to provision multiple servers for redundancy or load balancing
  • little emphasis on the provision of a corporate network
  • all of the processing is taking place within the cloud
  • service provider manages this underlying architecture
• principal network security job is to ensure that the clients accessing the services have not been compromised

Risks

• new technology, so use case and best practices still evolving
• critical and unavoidable dependency on the service provider
  • limited options for disaster recovery

Event-driven Orchestration

• depends heavily on the concept of event-driven orchestration to facilitate operations
  • e.g.,
    • multiple services are triggered when a client connects to an application
    • application needs to:
      • authenticate both the user and device
      • identify the location of the device and its address properties
      • create a session
      • load authorizations for the action
      • use application logic to process the action
      • read or commit information from a database
      • and write a log of the transaction
    • design logic differs from applications written in a “monolithic” server-based environment

Examples

• AWS Lambda
• Google Cloud Functions
• Microsoft Azure Functions