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Template settings, chasing the enabled value..

[Deleted User][Deleted User] ✭
in ADC - Application Delivery
Posted by SvenA

Hi,

I am somewhat lost in the server/server port template wilderness. Any guidance would be greatly appreciated. I am trying to figure out which setting overrides the other on a server / server port.

Let's try a simple example: I have a pool of servers all serving content on server port 80. I am controlling the Server Port weight with a Server Port template. Everything looks okay, and I have an illusion of control, happily ignoring that weight can be set no less than four places for each server/server port. (I have to admit I have fiddled a bit with the various weight settings messing up the initial default values).

But one day I want to adjust the weight on one of my servers. I make a new server port template with the new weight and attach it to my server port. Nothing happens.. Then I try to adjust the server port weight setting individually on the server ports on each server. Nothing happens. Having no server templates, I ignore the weight setting there.. Then, when adjusting the weight on the server itself, the weight is adjusted correctly.. Hmprf..

As far as I can see there is no way of disabling the unwanted weight settings. I guess leaving all settings to their default values will do some magic. But wouldn't the world be a better place if the unused values were grayed out or something? Or if we could manually disable them?

Also, is there a command in cli to display the actual server weight setting?

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    [Deleted User][Deleted User] ✭
    edited February 2014
    Posted by ddesmidt

    As you mentioned there are multiple places to set up server weight.
    . SLB Server (slb server S-Test 1.1.1.1 + weight 10)
    . SLB Server port (slb server S-Test 1.1.1.1 + port 80 tcp + weight 10)
    . SLB Server Port Template (slb template port a + weight 10) and assign that template to your SLB Server port
    You mentioned 4. Can you tell me which one I missed?

    I'll talk to A10 engineering next week (I'm on the road now) to get an explanation on which ones are more prevalent and update the thread with the explanation.
    At the same time I'll open an enhancement to get that clarified in WebUI/CLI to help customers understanding which weight is currently used on the servers/ports.

    That said, what you faced sounds like a bug to me (I haven't been able to reproduce it though).
    When I applied a new template (with new weight) to my servers, the new weights have been applied immediately.
    So please can you open a A10 support ticket and A10 support will track that issue with you.
    Note: They will ask you a "show tech" for sure => attach that to your ticket from the beginning. That will save you time.

    Thanks,
    Dimitri
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    [Deleted User][Deleted User] ✭
    edited February 2014
    Posted by SvenA

    Sorry, my mistake. Apparently there are only 3 server weight options. I thought weight was an option in the server template as well, but it isn't. Connection limit, on the other hand, seems to be represented in all 4 places, (well, actually 6 if you count the VIP- and the VIP-port template as well), and is equally confusing to me. 

    I guess you have to adjust the server weight settings in order to achieve the results I see. I have not tested it yet, but if using default values on the server weight setting, the templates might kick in as expected. I will test this before I consider opening a support ticket.

    Thank you for quick and helpful response,
    Sven
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    [Deleted User][Deleted User] ✭
    edited July 2022
    Posted by ddesmidt

    Hi Sven,

    I'm glad you asked the question, so I've been able to improve my knowledge in this area 
    The rule of thumb is the "object" configuration always overwrites the "template" configuration.

    So here is the explanation for Weight and Conn Limit:

    WEIGHT
    • LB algo "weighted-LC" + "weighted-RR" AX looks at:
    1. SLB Server weight only (under "slb server S-Test 1.1.1.1 + weight")
    Note: There is no weight under SLB Server Template

    • LB algo "Service-weighted-LC" AX looks at
    1. SLB Server port weight (under "slb server S-Test 1.1.1.1 + port 80 tcp + weight")
    2. if SLB Server port not defined (default = 1), look at SLB Server Port Template weight (under "slb template port + weight") and assign that template to your SLB Server port

    • other LB algo, no weight setting is looked at


    CONNECTION LIMIT
    Note: All these settings can be combined.

    • Connection Limit on VIP (number max connections on the overall VIP for all ports) AX looks at:
    1. Virtual Server Template Conn Limit
    Note: There is no conn limit under VIP

    • Connection Limit on VIP port (number of max connections on that specific VIP port) AX looks at:
    1. Virtual Port Conn Limit
    2. If conn limit in VIP port not defined, look at Virtual Server Port Template Conn Limit

    • Connection Limit on Server (number of max connections on the server for all ports) AX looks at:
    1. SLB Server Conn Limit
    2. If conn limit in SLB Server not defined, look at SLB Server Template Conn Limit

    • Connection Limit on Server Port (number of max connections on that specific server port) AX looks at:
    1. SLB Server Port Conn Limit
    2. If conn limit in SLB Server Port not defined, look at SLB Server Port Template Conn Limit


    Dimitri
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    [Deleted User][Deleted User] ✭
    edited July 2022
    Posted by SvenA

    Ok, this makes sense. Thank you for a thorough and informative explanation. I guess it all boils down to intuitiveness in the web-gui then. And of course lack of user experience.. I have to admit I had overlooked the "Service-weighted-LC"..

    I must say I am impressed with this forum. Having the oppurtunity to reach out to core tech expertise this way is indeed very helpful.

    Thanks,
    Sven
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