Intro to Serverless with Azure Functions

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Intro to Serverless with Azure Functions

• Andriy Zelinskyy

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From IaaS to FaaS
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From IaaS to FaaS
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From IaaS to FaaS

• Azure Functions is a serverless compute service
  that enables you to run code on-demand without
  having to explicitly provision or manage
  infrastructure.

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Serverless. When?

• Is the app a small, usable building block, or can
  it be broken into small blocks?
• Do all the building blocks have well-defined
  inputs and outputs?
• Can I use existing development and build tools?
• Does the serverless platform support
• Receiving connections from my client?
• Interacting with the target datastore?
• A language I know?

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Serverless. How?
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Azure Functions Triggers Bindings

• Triggers are what cause a function to run. A
  trigger defines how a function is invoked and a
  function must have exactly one trigger. Triggers
  have associated data, which is often provided as
  the payload of the function.
• Binding to a function is a way of declaratively
  connecting another resource to the function
  bindings may be connected as input bindings,
  output bindings, or both. Data from bindings is
  provided to the function as parameters.

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Triggers Bindings
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Azure Functions Hosting Plans

• Consumption Plan
• Premium Plan
• App Service Plan
• The hosting plan you choose dictates the
  following behaviors
• How your function app is scaled.
• The resources available to each function app
  instance.
• Support for advanced features, such as VNET
  connectivity.

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Consumption Plan

• Instances of the Azure Functions host are
  dynamically added and removed based on the number
  of incoming events. On a Consumption plan, a
  function execution times out after a configurable
  period of time.
• Billing is based on number of executions,
  execution time, and memory used.
• The Consumption plan is the default hosting plan
  and offers the following benefits
• Pay only when your functions are running
• Scale out automatically, even during periods of
  high load

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Premium Plan(Preview)

• Instances of the Azure Functions host are added
  and removed based on the number of incoming
  events just like the Consumption plan. Premium
  plan supports the following features
• Perpetually warm instances to avoid any cold
  start
• VNet connectivity
• Unlimited execution duration
• Premium instance sizes (one core, two core, and
  four core instances)
• More predictable pricing
• High-density app allocation for plans with
  multiple function apps
• Billing for the Premium plan is based on the
  number of core seconds, execution time, and
  memory used across needed and reserved instances.
  At least one instance must be warm at all times.
• Consider the Azure Functions premium plan in the
  following situations
• Your function apps run continuously, or nearly
  continuously.
• You need more CPU or memory options than what is
  provided by the Consumption plan.
• Your code needs to run longer than the maximum
  execution time allowed on the Consumption plan.
• You require features that are only available on a
  Premium plan, such as VNET/VPN connectivity.

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Dedicated (App Service) plan

• Function apps can also run on the same dedicated
  VMs as other App Service apps.
• Consider an App Service plan in the following
  situations
• You have existing, underutilized VMs that are
  already running other App Service instances.
• You want to provide a custom image on which to
  run your functions.
• With an App Service plan, you can manually scale
  out by adding more VM instances. You can also
  enable autoscale

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Azure Functions Limitations
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Azure Functions 1.x vs 2.x

• Cross-platform development(runs on .NET Core 2)
• Built-In DI Framework

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Azure Functions Example
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Durable Functions

• Durable Functions are an extension of Azure
  Functions that lets you write stateful functions
  in a serverless environment. The extension
  manages state, checkpoints, and restarts for you.
• Provide stateful workflows using an orchestrator
  function, which can provide the following
  benefits
• You can define your workflows in code
• Other functions can be called both synchronously
  and asynchronously. Output from called functions
  can be saved to local variables.
• Progress is automatically checkpointed when the
  function awaits. Local state is never lost when
  the process recycles or the VM reboots.

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Durable Application Patterns
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Durable Application Patterns
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Durable Application Patterns
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Durable Functions Example
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Development Guideline
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Further Reading
How to Harness the Power of Serverless with Azure
in 2020