PI73088: LOAD BALANCER FOR IPV4 AND IPV6 DOES NOT PROVIDE A METHOD TO CONFIGURE A CLUSTER OR ADJUST CONNECTION CLEANUP VALUES

Fixes are available

APAR status

Closed as program error.

Error description

Add Load Balancer for IPV4 and IPv6 ability to configure
clusters and set fintimeout.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  IBM WebSphere Load Balancer for ipv4 and    *
*                  ipv6 users                                  *
****************************************************************
* PROBLEM DESCRIPTION: The Load Balancer for ipv4 and ipv6     *
*                      does not provide a method to            *
*                      configure a cluster or adjust           *
*                      connection cleanup values.              *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
1) Configuring a cluster ---
The Load Balancer for ipv4 and ipv6 does not provide a
function to configure a cluster. This is handled automatically
by the code but there can be rare cases when the user needs to
force LB to broadcast a network advertisement for the cluster.
This broadcast network advertisement is called a gratuitous
arp. Sending a gratuitous arp updates all devices on the local
subnet of the machine owning the IP address advertised.
If you have LB setup using a highavailability configuration
and change to a single LB setup, you may need to use the
cluster configure option to update devices on your network. By
default, most devices verify their arp entries every 20
minutes so this issue only occurs when the new single LB setup
is deployed quickly after previously having a HA environment.
2) Adjusting fintimeout ---
A TCP connection is comprised of a client port, client ip,
server port, server ip. When a connection completes, the
client port should not be available for reuse until the
"fintimeout" period expires. This is based upon the TCP
protocol to allow for receipt of delayed packets which may
arrive after a connection completes. The Load Balancer had an
internal value for this timeout and it was not configurable
prior to this apar. A need to tune this value can arise if you
are using NAT forwarding under a heavy traffic load or
receiving heavy traffic from a single IP address, for example,
using a traffic generator to test your deployment.

Problem conclusion

This apar is targetted for delivery with :
   8.0.0.14
   8.5.5.12
   9.0.0.3

Tooling is provided with this apar to allow users to configure
a cluster and to adjust the fintimeout setting. Future
enhanements may incorporate these commands into lbadmin and
dscontrol but they are not available using those interfaces at
this time.

To issue these commands, use the lbcommand tool found in the
<IBMULB_install_path>/servers/bin directory. File extension
naming will be dependent on the operating system.

The executor must be started for these commands to take
effect. These settings will not be saved to configuration
files. If you would like to have these settings
persist, add the commands to an appropriate user exit script.
See the adminimistrators guide for information about go
scripts (goIdle is for use in non-highavailability
deployments) and highavailChange scripts.

To configure a cluster:
lbcommand<.sh> cluster_ip set configure yes
A cluster IP must be used, hostnames not accepted. If the
cluster has servers defined that are using return addresses
for NAT forwarding, the return addresses will also be
configured. You can not configure any address other than
cluster defined cluster addresses.

To set fintimeout :
lbcommand<.sh> cluster_ip/port set fintimeout <value>
Wildcard values are not accepted. A cluster IP and a port
number must be specified. If the fintimeout value is not set
using this command, the load balancer for ipv4 and ipv6
version 8 will default to 120 seconds, versions 8.5.5 and
higher will default to 30 seconds. When adjusting the
fintimeout value on the load balancer, the corresponding TCP
timeout value should be adjusted on the backend servers.
Consult your operating sytem documentation for appropriate
settings.

Temporary fix

If using AIX, you can alias the cluster and return addresses
to the interface using ifconfig instead of using the LB
cluster configure option but be advised not to forget to
unalias if the load balancer is no longer active.

If adjusting the fintimeout due to heavy traffic using NAT
forwarding, you should also consider using multiple
returnaddresses. A server can only be defined to have a single
return address but return addresses can be unique for each
server.

Comments

APAR Information

APAR number
PI73088
Reported component name
WS EDGE LB IPV4
Reported component ID
5724H8812
Reported release
850
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-12-02
Closed date
2017-02-02
Last modified date
2017-02-14

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
WS EDGE LB IPV4
Fixed component ID
5724H8812

Applicable component levels

R800 PSY
UP

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"8.5","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
03 May 2022

Tips

PI73088: LOAD BALANCER FOR IPV4 AND IPV6 DOES NOT PROVIDE A METHOD TO CONFIGURE A CLUSTER OR ADJUST CONNECTION CLEANUP VALUES

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R800 PSY

Document Information

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