node command does not work with host name

First, you need to use 9.0.2. he he he...

Second, you need to use a few undocumented rule commands/events for resolving the name.

Also, I'd like to point out that there's a shortcut for getfield combined with findclass. If you pass a 3rd argument to findclass, it is used as a separator which causes the trailing portion of the class entry to be returned instead of the entire class entry. This allows findclass to be used where you would otherwise need to combine it with getfield.

Example:

 
 rule direct_name { 
    when HTTP_REQUEST { 
       set hostname [findclass "something" $::my_class " "] 
        Hold HTTP data until hostname is resolved 
       HTTP::collect 
        Start a name resolution on the hostname 
       NAME::lookup $hostname 
    } 
    when NAME_RESOLVED { 
       node [NAME::response] 80 
        Release the hold on HTTP 
       HTTP::release 
    } 
 } 
 

One caveat to this is that connections will be stalled indefinitely if the name is never resolved. In an upcoming release we are adding a timer command and TIMER_EXPIRED event where you could recover from no response.

Thanks for great info!

 

 

Can you share more on TIMER_EXPIRED?

 

I'm sorry, but you'll just have to wait until it's released for more detailed information. Currently, it's still under design. Basically, the goal is to have an event that is fired after a specified amount of time. This would allow cleanup and/or closing of stalled or otherwise hung connections. We still have some implementation details to work out, so I'm not willing to give out any more information at this time.

 

Why is this done via the NAME::lookup command. In the examples in the documentation the servername is user and not the ip-address. I would expect the TM to use the name for the node and assosiate the specific node to the result of the command. Is this a bug?

If you can point us to the incorrect documentation, we'll have it corrected. Unlike rules, pools, virtual servers and many other objects on the system, nodes/members are unnamed entities in BIG-IP's schema. Their lookup key is their IP address.

 

 

In order to map a name to an IP address, you need to use the resolver.

Hi unRuleY,

 

 

I have try the example in 9.0.3 and found that [NAME::response] command does not work. the problem is command [NAME::response] return empty string...

 

 

if you have tried, would you please post the command that works so that I can try and find out why my rule did not work.

 

 

Thanks in advance.

I will try to test tonight and report status back here.

Well, what I discovered is that there is a bit of configuration that is additionally needed in the tmm_base.tcl file. I am going out of town for a few days and I will post the necessary configuration changes when I return early next week. Maybe we can get Bl0ndie to post them in the meantime.

Hi, I placed a change request to add the ability to use the configured hostname in the node command. I looks like this will be added to one of the next releases. I will keep you informed about the progress.

 

Marcel.