Configure IBM® Load
Balancer on a server running Microsoft™ Windows™.
Before you begin
Install IBM Load
Balancer and assign two static IP addresses to it. The server selected
for the Load Balancer installation must reside on the same LAN segment
as the nodes to be clustered.
If you are using a load balancer
with TURN Servers, do not use this procedure. Instead, see the section Deploying a load
balancer with Sametime® TURN
Servers.
About this task
Configure IBM Load
balancer to support your cluster using MAC Address rewriting. With
this method, the Load Balancer receives a packet intended for the
cluster. It uses configured metrics to determine which node in the
cluster should process the message, and then sends the message back
out to the network, routing it to the appropriate node's MAC address.
Each
of the nodes in the cluster is configured with a loopback adapter;
when the packet is rewritten to the network, the appropriate node
will receive and process the packet.
Procedure
- Configure the nodes of the cluster.
For cluster
nodes running on Windows
Add
a loopback adapter with the IP address of the cluster on each of the
nodes of the cluster. For instructions, see the Load Balancer Administration Guide, which
can be downloaded from the WebSphere® Application
Server - Edge Components site.
- Configure port settings on the cluster nodes so that IBM Load Balancer can route the
packets properly:
IBM Load
Balancer requires every node in the cluster to use same port number
for both HTTP and HTTPS service (typically, port 80). If you have
configured your nodes to use unique port numbers, change them to the
same port now.
Tip: When configuring the ports, you
can use the wildcard * when specifying the host name for the HTTP
and HTTPS. This will listen on all interfaces configured in the system,
including the loopback adapter set up for the cluster.
- On the Load Balancer server, configure load balancing for
the cluster:
- Open a command window on the Load Balancer server.
- Start the Load Balancer's Dispatcher process by
clicking . right-click IBM Dispatcher (ULB),
and then click Start.
- If you are using IPv6 addresses, enable the processing
of IPv6 packets:
Run the following command while logged
in as the Windows administrator:
netsh interface ipv6 install
This
command enables processing of IPv6 packets. Issue this command only
once; thereafter, you can start and stop the executor as often as
you need. If you do not issue the command to enable processing of
IPv6 packets on these systems, the executor will not start.
- Start the executor function of the dispatcher:
- Add the cluster to the service:
dscontrol cluster add cluster's_fully_qualified_host_name
where
cluster's_fully_qualified_host_name is
the fully qualified host name that you assigned to the cluster when
you installed the Load Balancer; for example:
stms-cluster.example.com
- Add the cluster port:
dscontrol port add cluster's_fully_qualified_host_name@port
where
cluster's_fully_qualified_host_name@port is
the fully qualified host name that you assigned to the cluster when
you installed the Load Balancer, with the HTTP/HTTPS port appended
to it (typically port 80); for example:
stms-cluster.example.com@80
- Add the nodes for which this server will balance workload:
dscontrol server add cluster_host@port@primary_node
dscontrol server add cluster_host@port@secondary_node
where:
- Add the cluster to the executor:
dscontrol executor add cluster's_fully_qualified_host_name
where
cluster's_fully_qualified_host_name is
the fully qualified host name that you assigned to the cluster when
you installed the Load Balancer; for example:
stms-cluster.example.com
- Start the manager:
- Start the HTTP advisor for the port you are using (the
port you specified in the previous steps, typically port 80):
dscontrol advisor start http 80
- Now you can stop the service:
- Close the command window.
- Define server affinity with a "sticky time:"
By
default the Load Balancer will round-robin HTTP requests between the
cluster members, so that a single client may be routed to different
cluster members for subsequent requests rather than continuing to
be routed to the same cluster member. Since a client typically accesses
an online meeting every 30-40 seconds during the session, you may
want to enable server affinity for a Sametime cluster so that
the client continues to access the same server during a single meeting.
The
dispatcher component of IBM Load
Balancer supports a configurable "sticky time." This means that the
Load Balancer will remember which cluster member a client was routed
to; subsequent requests will "stick to" the same server until the
preset time expires. IBM recommends
a "sticky" time configuration of 60 seconds for a Sametime cluster.
Windows
- Start IBM Load
Balancer.
- In the navigation tree, select the Executor (the
Load Balancer's non-forwarding IP address, which appears under
its host name).
- Click Configuration Settings.
- In "Port-Specific Settings", change the Default
sticky-time settings from 0 to 60 seconds, and click Update
Configuration.
- Leave IBM Load
Balancer open for the next step.
- Save the Load Balancer settings:
- In IBM Load Balancer,
return to the navigation tree and right-click on the host name of
the Load Balancer you just configured (for example,
loadbal.example.com
).
- Click Save Configuration File as and
accept the default name (
default.cfg
).The
configuration settings stored in default.cfg
are
restored every time the server is restarted.
- Click OK.