ASP.NET Session State Management With Redis (Local Server Farm Testing)

CREATING SERVERS FOR SERVER FARM

Now we have to create local servers for our server farm. Since we are using different ports on localhost to act as multiple servers, we have to include their address in the windows host files. Add entry to the host file (C:\Windows\System32\drivers\etc\host) for three different servers i.e. load balancer (staging server in the diagram), server-a, server-b.



As you can see, we have configured three server addresses against localhost (127.0.0.1). Now to distinguish between them, we have to bind ports against them.

Go to IIS manager, right click on the “Sites” node and select “Add Website”. Add three sites i.e. load balancer, server-a and server-b. Use 9000 for the load balancer whereas 9001 is for server-a and 9002 is for server-b. Here is a screenshot on how I configured and added server-a.



If you added all the sites you should have the sites list like this,
 

Time to add the servers to the server farm. From IIS manager right click on the server farm node and select “Create Server Farm”.

Give your server farm a name (redis-testing-farm).



On the next page add your two servers (www.redis-testing-server-a.com, www.redis-testing-server-a.com ) with their respective http ports i.e. 9001 and 9002. Finish the step and click on the “No”button when rewrite rules window pops up.



DEFINE URL REWRITE RULES

We have to define the URL Rewrite rules. Just follow the steps below.

On root node select URL Rewrite



Click “Add Rule” from right action bar and select blank rule

• Give a name to your rule (redis-testing-farm-rule).
• Type( .* ) in pattern.

Expand condition node and add two conditions

C0ndition input	Check if input string	Pattern
{HTTP_HOST}	Matches the pattern	(www\.|^)redis-testing-server-staging.com
{SERVER_PORT}	Matches the pattern	9000

Expand the“Action” node

• Select “Route to Server Farm” from action type dropdown.
• Check “Stop processing of subsequent rules”.
• Apply rules.

Select redis-testing-farm and go to “Load Balance” option

• Select “Weighted round robin”
• Apply

Again select redis-testing-farm and go to “Server Affinity”

• Select “Client Affinity”.
• Apply

We have selected round robin as load balancer algorithm. It will evenly distribute your incoming requests to servers. Which means if a request comes for the first time to the load balancer server, it will be routed to server A. If the page is reloaded and request is sent again then it will be routed to server B. The servers will be switched back and forth every time a request comes in. I’ve added an index in every server and placed some demo text in it to give you some indications about which server the request is currently hitting. Here is a GIF for you,



CREATING A SAMPLE ASP.NET WEB APPLICATION AND DEPLOYING

• Download the attached code .
• Deploy the application in all the servers using file system (run your Visual Studio as administrator if you got access denied error).

Browse to localhost

• Servers will be toggled back and forth every time a new request is sent.
• But sessions are different for each server (server-a, server-b).

DOWNLOADING AND RUNNING (REDIS-SERVER) REDIS VIA NUGET

Install Redis x64 server from nuget or chocolatey.

Here is the command to put in the package manager console of Visual Studio.

Install-Package Redis-64.

And here you can install it from chocolatey,

https://chocolatey.org/packages/redis-64

• After installation double click on redis-server.exe to run the redis server.

• Run redis-cli from the command prompt.
• Type (keys *) to get all the stored keys.

TESTING SESSION STATE WITH REDIS-CLI

We are almost at the end, last of all we need a nuget package that will help us to store the session states in Redis. The package is called RedisSessionStateProvider. Here is the command to install it from package manager console,
Install-Package Microsoft.Web.RedisSessionStateProvider.

And to make Redis store our sessions, we need to add these lines to our web config file.



If it is already added, then all is okay. Let’s deploy the project again in your three servers and give it a spin, you will see all your session state persisted successfully.



As you can see I’m setting the text in a session variable in server A. Later on, that is shown in both the Result.aspx page of those two servers i.e. our session is persisted. If you see the source code, you will see that I’ve used two session variables, one for input in the textbox and another for the current date and time. Both are saved as encrypted keys in the redis store.