Advanced iRules: Tables

We’ve covered quite a bit of ground in the Getting Started with iRules and Intermediate iRules series. In this series, we’ll dive even deeper down the rabbit hole, starting with the table command. Th...
Updated Oct 02, 2023
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Cay_Jeglinski_1's avatar
Cay_Jeglinski_1
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Aug 09, 2018

Hi Jason, thank you for this article on tables in iRules. I use tables in iRules to share data between virtuals. In this case I share a master key containing a service name. Just recently I discovered the tables aren't sync anymore on multi tmm instances. Perhaps you have a clue to sync tables again? Here are my logs. I add a session key into a subtable on one proxy and read it from another:

 

Proxy 1:

 

Aug  9 07:00:51 apmmuc01 info tmm7[14294]: Rule /way-software/WAY-AppAuthenticate-V2.3.01.iRule : REQ-A42-log: access to auth 483a86b149b2cfd5
Aug  9 07:00:51 apmmuc01 info tmm7[14294]: Rule /way-software/WAY-AppAuthenticate-V2.3.01.iRule : REQ-A42-tbl: master key wayservices

Proxy 2:

 

Aug  9 07:00:51 apmmuc01 info tmm7[14294]: Rule /way-software/WAY-Authenticate-V2.1.03.iRule : APM-E02-log: session id is 483a86b149b2cfd5
Aug  9 07:00:51 apmmuc01 info tmm7[14294]: Rule /way-software/WAY-Authenticate-V2.1.03.iRule : APM-I03-tab: master key wayservices

By chance the two iRules share the same tmm.

 

This is where it fails:

 

Proxy 1:

 

Aug  9 07:34:29 apmmuc01 info tmm4[14294]: Rule /way-software/WAY-AppAuthenticate-V2.3.02.iRule : REQ-A42-log: access to auth c6c405d09094e2ab
Aug  9 07:34:29 apmmuc01 info tmm4[14294]: Rule /way-software/WAY-AppAuthenticate-V2.3.02.iRule : REQ-A42-tbl: master key wayservices

Proxy 2:

 

Aug  9 07:34:29 apmmuc01 info tmm1[14294]: Rule /way-software/WAY-Authenticate-V2.3.02.iRule : APM-E02-log: session id is c6c405d09094e2ab
Aug  9 07:34:29 apmmuc01 info tmm1[14294]: Rule /way-software/WAY-Authenticate-V2.3.02.iRule : APM-I03-tab: master key

The two iRules run on separate tmm. I use since 11.3 (2015) reliably, but recently I see this changed behavior. Do you have an idea what is wrong? The code itself is pretty simple:

 

log local0. "REQ-A42-log: access to auth $JWTsessionKey"
log local0. "REQ-A42-tbl: master key [table lookup -subtable $WayMasterTable $JWTsessionKey]"

set tableKey [table lookup -subtable $WayMasterTable $sessionKey]
log local0. "APM-E02-log: session id is $sessionKey]
log local0. "APM-I03-tab: master key $tableKey"

I would be more than happy I you could help. I assume I'm not the only one to use tables to share information between proxies.

 

Cheers,

 

Cay