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Problem(Abstract) |
If Site Selector is load balancing across a pair of
Network Dispatcher high-availability partners, there are steps you must
complete to configure the metric server component. |
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Resolving the
problem |
Metric server must be configured to listen on a new IP
address that is specifically for use by metric server. On the two
Dispatcher machines, metric server is active only on the active
Dispatcher.
To correctly configure this set up, complete the following steps:
- Configure the metric server to listen on the new local IP for its use.
It must not be left to respond on the local NFA address. Read the
"Advanced Network Dispatcher Functions" section regarding metric servers
in Chapter 14 in the Network Dispatcher Administration Guide.
- Site Selector should communicate only with the active Dispatcher;
therefore, you must start and stop metric server in the high availability
go* scripts. To start or stop MS correctly, the new MS-specific IP
must be aliased on the machine. The go* scripts must be modified to move
the MS IP around, like they move clusters around. Therefore, goActive must
move the Metric Server IP from the loopback to a physical adapter, and
goStandby must do the reverse. After moving the IP, the goActive script
must run metricserver to start MS. The goStandby script must run
metricserver stop to prevent MS from talking to Site Selector while in
Standby mode.
- Refer to the "Using Scripts" section in Chapter 14 of the Network
Dispatcher Administration Guide for information regarding Microsoft
Windows® 2000 operating system commands for moving the MS Loopback
adapter.
Note: You will not use ndconfig for this IP address.
- The goStandby changes include operating specific instructions as
follows.
- Solaris and Linux® systems
In the section of the goStandby script where the cluster address is moved
to the loopback, add commands to move the MS specific IP to the loopback
as well. Once completed, add the metricserver stop command to stop MS from
responding to Site Selector.
- AIX systems
In the goStandby script section, where the cluster address is moved to the
loopback, add commands to move the specific IP address to the loopback.
Next, add a route so you can communicate with the loopback alias. Run the
command route add <MS IP> 127.0.0.1. Then add the metricserver stop
command to prevent MS from further responding to Site Selector. After
Metric Server stops, the final step is to remove the loopback route. To
prevent any future confusion, add route delete <MS IP>.
ifconfig en0 delete
9.27.23.61 |
ifconfig lo0 alias 9.27.23.51 netmask
255.255.255.0 |
route add 9.27.23.61
127.0.0.1 |
metricserver stop |
#Sleep either max 60 seconds or until
the metricserver stops |
let loopcount=0 |
while [[ "$loopcount" -lt "60"
&& 'ps -ef |grep AgentStop| grep -c -v gr ep' -eq "1"]] |
do |
sleep 1 |
let loopcount=$loopcount+1 |
done
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- Microsoft® Windows® 2000
First you must have the MS Loopback adapter (called Local Area Connection
2 in the following example) installed on your machine with an IP address.
Add an unused private network type address to it, such as 10.1.1.1. After
the Loopback is configured, make the changes to the "go scripts".
goStandby will include the netsh command to move the Metric Server IP to
the MS Loopback Adapter. Then run the metricserver stop command.
call netsh interface ip add address
"Local Area Connection 2" addr=9.27.2.3.61 mask = 255.255.255.0 |
sleep 3 |
metricserver stop |
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Cross Reference information |
Segment |
Product |
Component |
Platform |
Version |
Edition |
Application Servers |
WebSphere Edge Server |
Load Balancer |
AIX, Linux, Solaris, Windows |
2.0 |
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Application Servers |
Runtimes for Java Technology |
Java SDK |
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