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Configure ARR on IIS Application serverRSS

7 replies

Last post Jan 19, 2021 04:01 PM by asokanm

  • Configure ARR on IIS Application server

    Jan 13, 2021 01:43 PM|asokanm|LINK

    HI Team,

    We have 2 IIS application server running in our environment, Our Load balancer pointing to IIS servers directly. To enable sticky session we plan to configure Application request routing (ARR) on each IIS application server.

    Is that possible to host Application and ARR in same IIS server ? 

    Regards,

    Ashok

  • Re: Configure ARR on IIS Application server

    Jan 13, 2021 05:51 PM|lextm|LINK

    asokanm

    To enable sticky session

    So your load balancer does not even support that out of the box?

    Lex Li
    Want to have a chat on the issues you meet? Book an appointment at https://buy.stripe.com/cN24ia0yi7sAdIA7sv
    ---------------------------
    This posting is provided "AS IS" with no warranties, and confers no rights.
  • Re: Configure ARR on IIS Application server

    Jan 13, 2021 05:59 PM|asokanm|LINK

    Hi Lex,

    Thank you for your reply.

    Our Load balancer don't have that feature, and we don't have NLB feature as well in our environment. thats why we are looking for ARR.

    Regards,

    ashok

  • Re: Configure ARR on IIS Application server

    Jan 14, 2021 06:26 AM|samwu|LINK

    Hi asokanm,

    asokanm

    Is that possible to host Application and ARR in same IIS server ? 

    It's impossiable. Application Request Routing is an extension to IIS, which enables an IIS server to function as a load balancer. With ARR, an IIS server can be configured to route incoming requests to one of multiple web servers using one of several routing algorithms, if it is on the same server, load balancing cannot be achieved.

    asokanm

    Our Load balancer don't have that feature, and we don't have NLB feature as well in our environment. thats why we are looking for ARR.

    How do you set up load balancing? What version of iis are you using?

    Best  regards,

    Sam

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  • Re: Configure ARR on IIS Application server

    Jan 14, 2021 07:05 AM|lextm|LINK

    Lex Li
    Want to have a chat on the issues you meet? Book an appointment at https://buy.stripe.com/cN24ia0yi7sAdIA7sv
    ---------------------------
    This posting is provided "AS IS" with no warranties, and confers no rights.
  • Re: Configure ARR on IIS Application server

    Jan 15, 2021 06:12 PM|asokanm|LINK

    Hi Samwu,

    Thank you for the reply.

    We have IIS 10 installed in our environment. We have in build proxy for load balancing, which doesn't have Sticky session feature.

    To enable sticky session we have 2 ARR servers on top of 2 Applications server.

    Regards,

    Ashok

  • Re: Configure ARR on IIS Application server

    Jan 19, 2021 07:25 AM|samwu|LINK

    Hi asokanm,

    asokanm

    To enable sticky session we have 2 ARR servers on top of 2 Applications server.

    I think you should first understand what are sticky sessions and how it works. when a client makes a first request to the server, a session is created (by default or usually as In-Proc Sessions) in the server memory for that user, all the subsequent requests use the same session object. Now as I said, the session is created in the memory of the server handling the very first request, and in the Load Balanced environment we have more than one servers serving the requests, so what if the second request goes to another server that does not have that session object in memory, it will create a big mess, so that is the use of Sticky Sessions. To use Sticky Sessions we configure the load balancer to send the request for a specific session to the server that has served the first request. This can create a problem in the Load Balanced environment because it may be possible with Sticky Sessions that some of the servers are fully loaded and some are actually free at that time. 

    Best regards,

    Sam

    IIS.NET forums are moving to a new home on Microsoft Q&A, we encourage you to go to Microsoft Q&A for .NET for posting new questions and get involved today. Learn more >
  • Re: Configure ARR on IIS Application server

    Jan 19, 2021 04:01 PM|asokanm|LINK

    Hi Samwu,

    The reason we keep 2 ARR server with sticky session enabled is to avoid the single point of failure. 

    Would you please help us to validate the following scenario, As I mentioned earlier we have 2 ARR servers with sticky session enabled and 2 APP servers (SSO enabled).

    The first request goes through ARR1 server and it reaches APP1, then session created successfully.

    If the ARR1 Server goes down our In house LB will switch and redirect the in coming request to the ARR2 server.

    In this case ARR2 server will redirect the incoming request to same APP1 server ?

    Will the existing session reflected automatically or new session will be created ? 

    Thank you,