Compute: App Service, State configuration

Question 1

Web App Scaling: Scale Up

Answer 1

You scale up by changing the pricing tier of the App Service plan that your app belongs to.

Get more CPU, memory, disk space, and extra features like dedicated virtual machines (VMs), custom domains and certificates, staging slots, autoscaling, and more.

Question 2

Web App Scaling : Scale Out

Answer 2

Increase the number of VM instances that run your app. You can scale out to as many as 30 instances, depending on your pricing tier.

The scale instance count can be configured manually or automatically (autoscale). Autoscale is based on predefined rules and schedules.

Question 3

App Service Plan Scaling: Metric-Based

Answer 3

Metric-based rules measure application load and add or remove VMs based on that load.

For example, do this action when CPU usage is above 50%. Examples of metrics are CPU time, Average response time, and Requests.

Question 4

App Service Plan Scaling: Time-based.

Answer 4

Time-based (schedule-based) rules allow you to scale when you see time patterns in your load and want to scale before a possible load increase or decrease occurs.

For example, trigger a webhook every 8am on Saturday in a given time zone.

Question 5

Creating an App Service: config choices

Answer 5

Requires a resource group and service plan.

Name: Must be unique
Publish: Host code or a docker container
Runtime stack: The stack to run the app (language, SDK)
Operating System: Linux or Windows
Region: ...

Question 6

App Service: Deployment Slots

Answer 6

Deployment slots are live apps with their own hostnames. App content and configurations elements can be swapped between two deployment slots, including the production slot.

Question 7

App Service: Application Insights

Answer 7

A feature of Azure Monitor that monitors your live applications.

(request rates, response times, failure rates, dependency rates, page views, load counts, user and session counts, performance counters)

Question 8

Azure Automation State Configuration

Answer 8

Azure Automation State Configuration is an Azure service built on PowerShell.

Used to make sure that the virtual machines (VMs) in a cluster are in a consistent state, with the same software installed and the same configurations.

Question 9

PowerShell DSC

Answer 9

Is a declarative management platform that Azure Automation State Configuration uses to configure, deploy, and control systems.

You specify the desired state and let DSC do the work to get there.

Question 10

The local configuration manager (LCM)

Answer 10

…is a component of the Windows Management Framework (WMF) on a Windows operating system.

The LCM is responsible for updating the state of a node, like a VM, to match the desired state.

Question 11

Every time the The local configuration manager (LCM) runs, it completes the following steps:

Answer 11

Get: Get the current state of the node.
Test: Compare the current state of a node against the desired state by using a compiled DSC script (.mof file).
Set: Update the node to match the desired state described in the .mof file.
You configure the LCM when you register a VM with Azure Automation.

Question 12

The local configuration manager (LCM) - Push mode:

Answer 12

Push mode: An administrator manually sends, or pushes, the configurations to one or more nodes. The LCM makes sure that the state on each node matches what the configuration specifies.

Question 13

The local configuration manager (LCM) - Pull mode

Answer 13

Pull mode: A pull server holds the configuration information.

The LCM on each node polls the pull server at regular intervals, by default every 15 minutes, to get the latest configuration details.