PI95067: UNABLE TO ADD SERVERS TO LOAD BALANCER FOR IPV4

8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21

APAR status

• Closed as program error.

Error description

• LLB has a limitation for the number of return address
  (max: 64) now. If the customer try to add server to cluster
  with returnaddress (which will cause over 64 returnaddresses),
  the customer fail to add server.
  

Local fix

• Reduce tne number of returnaddress.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:  IBM WebSphere Application Server Load       *
  *                  Balancer for IPv4 users                     *
  ****************************************************************
  * PROBLEM DESCRIPTION: The Load Balancer for IPv4 (legacy      *
  *                      load balancer) is unable to add a       *
  *                      server after 64 unique return           *
  *                      addresses.                              *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The Load Balancer for IPv4 has a limit on the number of return
  addresses (used when defining servers with NAT forwarding).
  The limit was 64 and after 64 return addresses were used, a
  server could not be added with a new return address.
  

Problem conclusion

• The number of return addresses has been increased to 256 but
  64 should be sufficient for most users. The return address
  needs to be on the same subnet as the load balancer and
  clusters and using a large number of return addresses could
  quickly exhaust the available IP addresses for a subnet.
  Servers defined on different ports do not benefit from using a
  different return address.
  
  APAR targetted for fixpack inclusion in 8.5.5.14
  The Load Balancer for IPv4 is not available in WebSphere
  Application Server Network Deployment version 9.
  The Load Balancer for IPv4 and IPv6 does not have a limit on
  the number of return addresses.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBS LOAD BALAN

• Fixed component ID

  5724H8811

Applicable component levels

• R850 PSY

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