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mkyrc
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Sep 17, 2024
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GTM pool is OFFLINE even if pool members are UNKNOWN

Hi,

Maybe someone can clarify me this situation. I didn't found it in documentation.

  • generic host (with no monitors) has two virtual servers (also no monitors here). the state of server and virtual servers is unknown (that expected).
  • state of the pool is OFFLINE (why?? this is not clear for me), but (all two) members are UNKNOWN
  • wide IP is OFFLINE because poll has no available members (members are unknown, not unavailable)
  • dns response to wide ip returns two IPs (IP adresses of both members).
    • it's ok in this case, because return code on failure is (by default) disabled
    • when I enable 'return code on failure', response is empty
  • Note: when one member is disabled (or down based on temporary monitor), dns response return only one IP - IP of the unknown member. That's correct, but pool state and wide ip state are offline.

My question is: Why is pool state OFFLINE when pool members states are UNKNOWN?

I think he should be unknown. When the same situation occurs on LTM, state of pool is unknown, not offline. Does GTM behave differently??

TMOS version: 17.1.1.3

 

Here is simple test configuration: 

# gslb domain (wide ip) 
gtm wideip a /testTenant/testApp/test.my.local { 
    pools { 
        /testTenant/testApp/testPool { order 0 } 
    } 
} 

# gslb pool 
gtm pool a /testTenant/testApp/testPool { 
    alternate-mode global-availability 
    fallback-mode none 
    load-balancing-mode global-availability 
    members { 
        /Common/server1:vs1 { member-order 0 } 
        /Common/server1:vs2 { member-order 1 } 
    } 
} 

# gslb servers 
gtm server /Common/server1 { 
    datacenter /Common/testDc devices { 
        0 { 
            addresses { 10.1.1.1 { } } 
        } 
    } 
    prober-fallback none 
    product generic-host 
    virtual-servers { 
        vs1 { destination 10.1.1.11:0 } 
        vs2 { destination 10.1.1.12:0 } 
    }
}
  • I found article describing this behavior (https://my.f5.com/manage/s/article/K10302440). It answers my question, but it's still confusing to me.

  • I found article describing this behavior (https://my.f5.com/manage/s/article/K10302440). It answers my question, but it's still confusing to me.