AZ204 Flashcards by Dinand ten Hooven

What is serverless

Fully managed cloud services

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Name 5 characterics of Serverless?

Highly elastic
Highly available
Highly scalable
Highly durable
Secure by default

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What happens to infrastructure in a serverless context

Is abstracted away.

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What is billing based on with a serverless application?

On the execution of your business task

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What does it mean to Scale to zero and what is benefit as apposed to On-premise or non-serverless applications?

Not using it means it doesn’t cost you anything, and the benefit is that you don’t pay for idling servers on premises or in the cloud.

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What does FaaS mean?

Function as a servers

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Describe a FaaS

Event-driven trigger functions based on event data and/or emit event data.
Multiple functions can be orchestrated together to create a serverless app
They run only when triggered by several types of triggers

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What does it mean for a function to be truly serverless?

It’s fully managed and it scales to zero

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What is Azure functions

A FaaS service by Azure, that allows developers to focus on writing code and not worrying about underlying infrastructure.

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What high-level things are defined in a Functions App?

Hosting, Runtime and global configuration

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What is an output binding?

An output binding is a data sink that receive outputted data from an Azure Function

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Is a storage account needed to operate a function app?

yes

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When you delete a storage account, what happens to your function app?

The function app is not deleted but it doesn’t work anymore

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Name 4 types of storage in a storage acccount?

Blob storage
Azure Files
Queue Storage
Table Storage

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What is contained in a function.json file?

Configuration of a single function defining the bindings

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What are the 3 levels of authorization in Azure Functions?

Anonynous,
Function,
Admin

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What would you use streaming logs for when talking about Function Apps

You can view logging stream from your functions app for debugging.
You can also hook up application insights for live metrics stream and live logging

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Name several qualities of Azure functions

lightweight,
Serverless,
Write and deploy,
Triggered by events
No infrastructure,
Little to no maintenance,
Built, tested and deployed using the azure portal on windows only,
Easy to update,
Pay when running,
Industry standard communications with APIs, databases, libraries

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What does it mean to have a cold start in azure functions?

If no azure functions are running, it might take some time for the azure function app to start before responding to requests.

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Name 5 types of solutions of that Azure Functions are great for?

Processing data
Integrating system
IoT solutions
Simple APIs
Microservices

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What do you call a output for an Azure Function?

Binding

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What do you call the thing that starts an Azure Function?

Trigger

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What is the difference between Azure Functions and Logic Apps

Both process serverless workloads but functions are a serverless compute services and a logic app is a serverless workflow

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What do you call a Azure Function with complex orchestrated actions?

Durable Functions

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What are functions or steps in Azure Logic Apps called?

Actions

How do you monitor Logic Apps?

Azure Portal and Azure Monitor Logs

How do you monitor an Azure Function?

Azure Application Insights

How is execution context of logic apps described?

It supports 'Run-Anywhere' scenarios

What is Azure App Service Webjobs?

A code-first integration service designed for developers

How is monitoring done in Azure App Service Webjobs?

Azure Application Insights

Can you test and develop Azure Functions in the browser?

yes

Can you test and develop Azure App Service Webjob in the browser?

Can you integrate Webjobs with Azure Logic Apps?

Can you integrate Azure Functions with Logic apps?

Yes

Can you integrate Azure Functions with Logic apps?

Yes

Name 7 Azure function triggers?

Timer, Storage queue and blobs Servicebus topics and queues Cosmos Db Event hubs Http / Webhooks Event grid

Name 6 trigger events for azure app service webjob?

Timer, Storage queues and blobs Service bus queues and topics Cosmos Db Event Hub File system

Name the 5 hosting plans for azure functions

Consumption, Premium, Dedicated, App Service Environment, Kubernetes

What is dictated by the hosting plan for a Azure Function?

Scalability behaviour Available resources Support for advanced functionality such as Azure Virtual Network

Describe the ASE hosting plan for Azure Functions?

App Service Environment (ASE) is an App Service feature that provides a fully isolated and dedicated environment for securely running App Service apps at high scale.

Describe the Kubernetes hosting plan for Azure functions?

Kubernetes provides a fully isolated and dedicated environment running on top of the Kubernetes platform.

On a dedicated service plan, what is the reason you should have the "Always on" option enabled?

This will make sure that the function runs correctly. On a consumption plan, this is not necessary because the function is activates automatically which isnt the case for dedicated functions.

Why does an Azure function need an storage account to run?

An Azure function may rely on storage triggers and it is used to store logging. This must be a storage account that supports tables and queues

What determines the number of instances of azure functions running at once on consumption and premium hosting plans?

The number of events trigger a particular function

What is the limit of a Azure function memory and how many CPU on a consumption plan?

1.5 Gb and 1 CPU

Where are the Azure functions code files stored? And what happens when the azure function is removed?

On the main storage account associated with the function. The code files are deleted beyond recovery after the Azure Function is deleted

What is the job of the Scale Controller in the context of Azure Functions?

Monitors the rate of events and determines to scale in or out. It can scale to zero. This means a cold start (thus latency) happens on the next event

What is the number of maximal instances a single function app can scale to?

200

Does an instance of a functions app process a single event or multiple?

Multiple event, thus there is no real limit to the number of concurrent execution?

Which Azure Functions hosting plans is best when predictive scaling and costs are required?

Dedicated plan

An organization wants to implement a serverless workflow to solve a business problem. One of the requirements is the solution needs to use a designer-first (declarative) development model. Which service meets this requirement? Functions, Webjobs, or Logic apps?

Logic apps

What are the 3 datatypes an input binding can have?

binary, string, stream

What property is used to refer a function to its configuration?

By name

Which of the following is required for a function to run? 1. Trigger, 2. Binding, 3. Both

1. Trigger

Which of the following supports both the in and out direction settings? 1. Trigger, 2. Binding, 3. Both

2. Binding

How do you call a application pattern where a sequence of Functions is executed in a specific order?

Function Chaining

How do you call a application pattern where multiple functions are running in parallel and then wait for all functions to finish?

Fan out / Fan in

Describe a Async Http API pattern where you are using Azure Functions?

Some functions are triggered by HTTP calls to interact other azure services and some functions are doing work that is triggered by whatever happens on those services.

What is the pattern is following an example of? A polling function that checks whetehr or not a specific condition is met. Such as a periodic cleanup job.

Monitor pattern

In the context of durable functions, what are activity functions?

Specific units of work that are processed in a durable function, either in parallel, serial or both.

What is a task hub?

A task hub in Durable Functions is a logical container for durable storage resources that are used for orchestrations and entities.

Can activity functions interact with resources in different task hubs?

What does a task hub consist of?

- One or more control queue - One or more work-item queue - One History table - One instances table - One storage account with one or more lease blobs - A storage container containing large message payloads, if applicable

Task hub names rules are

only alphanumeric letters start with a letter between 3 and 45 characters

What is an orchestrator function for?

To orchestrate the execution of other durable functions within a functions app

In an orchestor function, when a VM reboots, is the local state still available

Yes, local state is never lost.

What is the default value of a orchestration instance id?

Guid

What would be the reason to change from a default generated Orchestration instance id to a user created id?

When there is a one to one mapping between the function and an external application-specific entity

Describe the event sourcing design pattern?

Capturing all application state changes as a sequence of events rather than saving the state itself

What is a sub-orchestration?

Orchestrator functions can other durable orchestrator functions which are called sub-orchestration functions

What are durable timers used for?

Sets up timeout handling on async actions

What are external events most commonly used for?

Handling human interaction within an orchestration

Are race-conditions possible within an orchestration?

No, they are single threaded.

What can you use to mitigate a race condition occuring when orchestration interact with external systems?

you can use the LockAsync method of .net to mitigate

Which of the following durable function types would you use to read and update small pieces of state? Orchestor, Activity or entity

Entity

Which application pattern would you use for a durable function that is polling a resource until it meets a specific condition? Function chaining, Fan out / Fan in, Monitor

Monitor

What 3 type of applications are Azure App Services most useful for?

Hosting Web applications Mobile Backends REST APIs

What 2 OS does a Azure App Service run on?

Windows Linux

Is auto-scaling automatically built-in a azure app service?

Yes

Is it possible to run multiple app services on the same app service plan?

Yes

What aspects are defined by Azure App Service Plan?

Region, No. of VM instances Size of VM instances Pricing tier

Name 4 categories of App Service plans?

Shared compute Dedicated compute Isolated Consumption

Is it possible for an Azure App Service to scale out on a free or shared app service plan?

You have two Hyper-V hosts named Host1 and Host2. Host1 has an Azure virtual machine named VM1 that was deployed by using a custom Azure Resource Manager template. You need to move VM1 to Host2. What should you do?

From the Redeploy blade, click Redeploy.

You have downloaded an Azure Resource Manager template to deploy numerous virtual machines. The template is based on a current virtual machine, but must be adapted to reference an administrative password. You need to make sure that the password is not stored in plain text. You are preparing to create the necessary components to achieve your goal. What do you need to achieve this goal?

Azure keyvault and an access policy

In the azure cli, what does the command: `az webapp up` do?

Deploying a html and css webapp

Which of the following App Service plans supports only function apps? 1 Dedicated, 2. Isolated, 3. Consumption

Consumption

In the azure portal, where can you find the application settings of an Azure App Service resource

Under Settings -> Configuration -> Application settings

In which of the following app configuration settings categories would you set the language and SDK version? 1. Application settings, 2. Path mappings, 3.General settings

General settings

Which of the following types of application logging is supported on the Linux platform? 1. Web server logging, 2. Failed Request tracing, 3. Deployment logging

Deployment logging

Can App Service Autoscaling be triggered on a schedule?

Yes

Can autoscaling App service change the CPU, memory or storage capacity?

No, it only changes the number of web server instances

Is autoscaling automatically included in all service plans?

Name 6 metrics where rules can be made out of for app service autoscaling?

CPU percentage Memory usage Disk queue length Http queue length Data in Data out

Describe autoscaling

A scale in / scale out solution

What kind of system is Azure Cosmos Db?

A globally distributed database system