ARR Best Practices, Multiple sites w/ Multiple RulesRSS

6 replies

Last post May 26, 2010 05:55 PM by zippo762000

  • ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 01:19 PM|zippo762000|LINK

    I'm looking for best practices for an ARR pair of servers in front of our web sites (server farms ww1,ww2,ww3).  We want to move a bunch of our existing rules into ARR for each site.  These rules will be different per site, routing to the 3 farms.  The issue is that we its going to be a bit messy as far as the look and feel in the gui (has anyone made a better one?) , and the implementation and support.  The only thing i can think of is to add a condition to each rule, which is named something like ww1-rule-A, that has a condition of {http-host} being ww1.  Doing this for each condition can get ugly w/ 50+ rules per site  Is there a better way i can do this?

  • Re: ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 04:03 PM|wonyoo|LINK

    A couple of questions:

    - How are the "sites" differentiated?  They are separate IIS sites (either unique IP or different host name binding?)

    - Do you trust the rules that are written for each site?  (ie. would you let the site admin (not the server admin - which would be you) to change the site rules that can potentially open proxy based security concerns, such as hiding behind the proxy and sending malicious requests.)

     

    If your answer is "yes" to both of above (ie. they are different IIS sites and yes, you either trust or manage the rules on your own), then there is a simplified way of writing the rules per site - but if your answer is no, then you will have to manage it centrally and define the conditions.  Let me know what your situation looks like and I can make additional suggestions.

    ARR application Request Routiing

  • Re: ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 04:26 PM|zippo762000|LINK

    Thanx for the reply.

    They are completely different IIS sites, and yes, I am the rule creator and owner.

  • Re: ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 04:43 PM|wonyoo|LINK

    Okay, in that case, you have some options.  To be clear, I would not recommend this to others who do not trust the site admins to write the rules.

    As you called out, ARR is the server level feature and it does not have per site differentiation.  At the same time, ARR relies on URL rewrite to inspect the incoming URLs and make the routing decisions based on that.   Unlike ARR, URL rewrite is scoped to both server and site - and ARR honors both the "globalRules" (set at the server level in applicationHost.config) and rewrite rules in web.config for each of the site.

    So, you could either:

    1) Define all the rules in globalRules but you will have to use the conditional statement to apply the rules selectively to different sites  -- or --

    2) Don't define any rules in globalRules - instead, write the rules per each site (without any site specific conditions).

    Hope this helps.

     

    ARR application Request Routiing

  • Re: ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 04:57 PM|zippo762000|LINK

    thanks again for the reply.  The goal is to remove rewriting from the specific sites and web servers and move the rules to the dedicated ARR servers.  Was hoping for a cleaner way than putting in spefic conditions and unique names for all rules per site (ww1-rulea, ww2-rulea, etc).  We would like our incomming urls cleaned before hitting the web servers and not having the web servers themselves interrogate each url.  Next iteration request would definately be a site filter. 

    arr multiple sites

  • Re: ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 05:48 PM|wonyoo|LINK

    I see - I am curious to understand what your goal is.   Are you doing this for security purposes?  Ease of managing rules in central location?   Want the content servers to not "waste" cycles rewriting URLs?   If I can understand your objective, perhaps I can suggest different options.

     

  • Re: ARR Best Practices, Multiple sites w/ Multiple Rules

    May 26, 2010 05:55 PM|zippo762000|LINK

    Security is not the big issue.  Centeralized rules and rule processing offloading are the two main reasons.  We are in the middle of some site redisigns  where 80% of our URLs will initially be redirected or rewriten, after that, we estimate 30-40%.  We have some extensive ruls and scripts providing up to the minute rewrite maps from various databases.    I would like to handle that traffic before it a single packet reaches the web servers.