5.4.3 Service Lock Using a Load Balancer

This subsection describes how to execute a service lock using a load balancer. You can execute a service lock using a load balancer for a Web front system. There are two methods of service lock using load balancer as follows:

Normal service lock
Partial service lock

The following is the description for how to execute each method:

Tip: Execute a service lock using a load balancer when the load balancer is not managed by the Smart Composer functionality. You use the cmx_stop_target command, to execute a service lock when the load balancer is managed by the Smart Composer functionality. For cmx_stop_target commands, see cmx_stop_target (Stop a Web system or a service unit) in the uCosminexus Application Server Command Reference Guide.

Organization of this subsection

(1) Normal service lock
(2) Partial service lock

(1) Normal service lock

Execute a normal service lock using load balancer by either of the following methods:

Changes the request distribution destination of a load balancer

Prepare a Web server other than the normally used Web server for service lock and switch the request distribution destination to a Web server used for locking the service at the service lock time. In the Web server used for service lock, set such that to display an error page.
Stops the load balancer

This method stops the load balancer, and then stops the reception of requests. The requests already sent to the Web server are executed as it is.

Note that for lifting the service lock, switch the request distribution destination once again or start the load balancer.

For the procedure, follow the usage methods of the load balancer in use.

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(2) Partial service lock

When a Web server that receives a request and a J2EE server that executes the request are made redundant using a load balancer, you can stop only a part of the Web application configuring the service, without stopping the entire service. This locking method is called Partial service lock.

Note that a system with the following configuration enables Partial service lock of a Web application:

System using a load balancer
Web server and J2EE server are redundant, and Web server and J2EE server are in the ratio of 1:1 or 1:N (N is an integer greater than 1)

You can use the Partial service lock of a Web application by changing the request distribution destination using a load balancer, and not distributing the requests to the node locking the service. For execution methods, confirm the usage methods of the load balancer.

Tip: When executing Partial service lock using a load balancer, the session is disconnected for the request using the session created for a Web server to be stopped. In this case, the session needs to be reconnected for a running Web server. However, when the session failover function is used, part of the information of the session is inherited. For the session failover function, see 5. Inheriting Session Information Between J2EE Servers in the uCosminexus Application Server Expansion Guide.

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