In this article by Ashraf Khan, the author of the book Microsoft IIS 10 Cookbook, helps us to understand the following topics:

Understanding IIS 10
Basic requirements of IIS 10
Understanding application pools on IIS 10
Installation of lower framework version
Configuration of application pool on IIS 10

(For more resources related to this topic, see here.)

Understanding IIS 10

In this recipe, we will understand how to work with IIS 10's new features. We will have an overview of the following new features added to IIS 10:

HTTP/2
HTTP/2 requests are now faster than ever. This feature is active by default with IIS 10 on Windows Server 2016 and Windows 10.
IIS 10 on Nano Server
IIS 10 is easy and quick to install on Nano Server. You can manage IIS 10 remotely with PowerShell or the IIS Manager console. Nano Server is much faster and consumes less memory and disk space that the full-fledged Windows Server. Rebooting is also faster so that you can manage time effectively.
Wildcard host headers
IIS 10 support the subdomain feature for your parent domain name. This will really help you manage more subdomains with the same primary domain name.
PowerShell 5 cmdlets
IIS 10 adds a new, simplified PowerShell module for quick and easy management. You can use PowerShell to access server-management features remotely. It also supports existing WebAdministration cmdlets.
FTP
FTP is a simple protocol for transferring files. This system can transfer files inside your company LAN and WAN using the default port, 21. IIS 10 includes an FTP server that is easy to configure and manage.
FTPS
FTPS is the same as FTP, with the only difference that it is secure. FTPS transfers data with SSL. We are going to use HTTPS port 443. For this, we need to create and install an SSL certificate that encrypts and decrypts data securely. SSL ensures that all data passed between web server and browser remains private and consistent during upload and download over private or public networks.
Multi-web hosting
IIS 10 allows you to create multiple websites and multiple applications on the same server. You can easily manage and create a new virtual directory located in the default location or a custom location.
Virtual directories
IIS 10 makes it easy to manage and create the virtual directories you require.

Understanding application pools on IIS 10

In this recipe, we are going to understand application pools. We can simply say that application pool is the heart of IIS 10. Application pools are logical groupings of web applications that will execute in a common process, thereby allowing greater granularity of which programs are clustered together in a single process. For example, if you required every Web Application to execute in a separate process, you simply go and create an Application Pool for each application of different frameworks versions.

Let's say that we have more than one version of website, one which supports framework 2.0 and another one supporting framework 4.0 or different application like PHP or WordPress. All these website process are managed through application pool.

Getting ready

To step through this recipe , you will need a running IIS 10. You should also be having Administrative privilege. No other prerequisites are required.

How to do it...

Open the Server Manager on Windows Server 2016. Click on Tools menu and open the IIS Manager.
Expand the IIS server (WIN2016IIS) this is the localhost server name WIN2016IIS. We get the listed application pools and sites.
In Application Pools, you will get IIS 10 DefaultsAppPool as shown in above figure, also you get Actions panel in right side of the screen where you may add application pools.
Click on DefaultAppPool, then you will get the Actions panel of DefaultAppPool. Here you will get an option for Application Pool Tasks highlighted in right side, where you may Start, Stop, and Recycle the services of IIS 10.
In Edit Application Pool section, you can change the settings of application pool as Basic Settings..., Advanced Settings..., Rename the application pool and you may also do the Recycling...

How it works...

Let's take a look at what we explored in IIS Manager and Application Pools. We understood the basics of application pools and the property where we can get the changes done as per our requirement. IIS 10 default application pool framework is v4.0 which is supported upto v4.6, but we will get some more option for installing different versions of application pool. We can easily customize the application pool, which helps us to fulfill our typical web application requirement.

We have several options for application pool in action pane. We can add new application pool, we can start, stop and recycle the application pool task. We can do the editing and automated recycling.

Now we are going to learn in the next recipe more about application pools for Installation of lower framework version.

Installation of lower framework version

In this recipe, we are going to install framework 3.5 on Windows Server 2016. Default IIS 10 has the framework 4.0. We will install the lower version of framework which supports the web application of Version 2.0 to Version 3.5 .NET framework.

Let's start now if you have your own web application which you had created a few years back and it was developed in v2.0 .NET framework. You want to run this application on IIS 10. We are going to cover this topic in this recipe.

Getting ready

To step through this recipe you need to install framework version3.5, v3.5 framework is based on v2.0 framework. You will need a Windows Server 2016. You should be having a Window Server 2016 Operating System media for framework 3.5 or Internet connected on Window server 2016. You should have Administrative privilege. No other prerequisites are required.

How to do it....

Open the Server Manager on Windows Server 2016, click on highlighted Add roles and features option.
Click on Next until you get the Select features wizard. You can see the next figure.

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Click on Features panel and click on the check box .NET Framework 3.5 Features. It will also install the 2.0 supported framework. Move to next wizard as shown in figure.
There is a warning coming before the installation: Do you need to specify an alternate source path? One or more installation selection are missing source files on the destination.
We have to provide the Installation media sourcesSxS folder path. Click on Specify an alternate source path. See next figure for more details.
Here we have Windows Server 2016 media in D:drive. This is the media path in our case which I have downloaded but in your case it can be different path to locate where you already had downloaded. There is a folder which is called sources and sub folder(SxS). Inside framework 3, installation file is available. You may see the next figure.
Now you know where the source folder is. Come to confirm Screen and click on Install. The next figure shows Installation progress on WIN2016IIS.
Click on close when installation is completed, you have framework 3.5 available on your server.
Now you have to check whether framework 3.5 has been installed or not. It should be available in features wizard.
Open the Server Manager, click on Add roles and features.
Click next and next until you get the Select Features wizard. You will see .NET framework 3.5 check box checked with gray color which is disabled. You can not check and uncheck the checkbox. You can see the next figure.
As shown in the preceding figure, it has been confirmed that .NET framework 3.5 has been installed.
This can be installed through PowerShell. We can install directly from Windows Update, you need Internet connectivity and running Windows Update service on Window Server.

How it works...

In this recipe, IIS administrator is installed in the framework v3.5. The version 3.5 framework on window server 2016 helps us to run built in application .NET framework v2.0 or v3.5.

The framework v3.5 processes the application which is built in framework v3.5 or v2.0. We also find out where is the sourcesSxS folder, after installation we verified that this .NET framework v3.5 is available.

We are going to create application pool which will support the .NET framework v3.5.

Configuration of application pool on IIS 10

In this recipe, we will have an overview of application pool property. We will check the default configuration of Basic Settings, Recycling and Advanced Settings. This is very helpful for developer or system administrator as we can do the configuration of different property of different application pool based upon application requirement.

Getting ready

For this recipe, we need IIS 1o and .NET framework of any version which is installed on IIS 10. You must have Administrative privilege. No other prerequisites are required.

How to do it...

Open the Server Manager on Windows Server 2016. Click on Tools menu and open the IIS Manager.
Expand the IIS server (WIN2016IIS). We get the listed Application Pools. You may see in the next figure.
Now we have already created application pool which is displayed in Application Pools. We created 2and3.5AppPool, Asp.net and DefaultAppPool (Default one).
In the Actions panel, we can add many application pools and we can set any one of the created application pool as default application pool. The default application pool helps us when we are creating a website. The default application pool will be selected as an application pool.
Select the 2and3.5AppPool from application pools. You will see the Actions pane having a list of available properties in which you can do some changes if needed. The version of 2and3.5AppPool is v2.0, you can see in the next figure.
See the Actions panel, Application Pool Tasks and Edit Application Pool which we selected. From the Application Tool Tasks we can Start, Stop and Recycle... the application pool.
Now let's come to the basic property of application pool. Click on Basic Settings... from Edit Application Pool, see the next figure which will appear after clicking.
Basic Settings... is nothing but a quick settings to change limited number of things. We can change the .NET framework version to framework v4.0 or framework v3.5(version 2.0 is updated version 3.5).
We can change the Managed pipeline mode to Integrated or Classic, also we can check or uncheck the start option.
Next is the Advanced Settings... which has more options for customization of relevant Application Pool.
Click on Advanced Settings..., the next figure will open.
We have more settings option available in Advanced Settings... window. You may change the .NET framework version, you can select 32 bit application support true or false. Queue Length is 1000 by default. You may reduce or increase as you need. Start Mode should be OnDemand or Always Running.
We can also customize utilization of CPU which helps you to manage the load of each application and their performance.
Process Model will help you to define task for application pool availability and accessibility. We can see more about application pool in next figure.
Rapid-Fail Protection is generally used for fail over. We can setup the fail over server and configuration.
Recycling is to refresh the application pool overlapped. We can set a default recycling value.
We can do more specific settings through Recycling settings by clicking on Recycling.... You may see your recycling conditions window in the next figure.
Recycling is based on conditions like virtual memory usage, private memory usage, specific time, regular time intervals and fixed number of request, also it will generate you a log file which will help you understand which one was executed at what time. Here you will set the fixed intervals based on time and based on number of request, or specific time and based on Memory utilization, virtual and private memory. Click Next.
In the Recycling Events to Log window, we generate log on the recycling events.

How it works....

In this recipe we have learned three properties of IIS Application - Basic property, Advanced property and Recycling. We can use these properties for web application which we will host in IIS server to process through the application pool. When we are hosting a web application, there is always some requirement which we need to configure in application pool settings.

For example, our management decides that we need to limit the queue of 2and3.5apppool application. We can just go to advance settings and change it.

In the next section, we are going to host v4.0 .NET framework website and we will make use of application pool v4.0.

Summary

In this article, we understood application pools in IIS 10 and how to install and configure them. We also understood how to install a lower framework version.