You can set up your system to perform automatic application rollout for your high
availability applications. The automatic application rollout update process stops or pauses each
application server that is hosting a cluster member that needs updating.
Before you begin
Determine which application servers are hosting the cluster members that need
updating.
About this task
If you have a high availability application that frequently requires updates, you might
want to automatically control the roll out of these updates. When you set up the rollout update
process, you must decide whether you want the application servers to stop or pause while the update
is made to an application. If you want the servers to pause, you must configure the node agent to
allow the rollout update process to pause and resume the servers. You do not have to make any
configuration changes if you want the rollout update process to stop and start the servers. However,
if the rollout update process stops and starts the servers, the process takes much longer to
complete.
When an application server pauses, all requests already in the queue for that server
are allowed to complete, but no new requests are accepted. Both the sysplex distributor and the WebSphere®
Application Server web server plug-in route work away from the server that is paused. After all of
the requests that are assigned to that server complete, the application update process starts on
that server.
When the update process is complete, the listener for that server resumes and
the sysplex distributor and the WebSphere Application Server web server plug-in assign new work to that
server. This process is repeated for all of the other servers in the cluster until all of the
affected cluster members are updated.
To prepare your system to automatically roll out updates
to a high availability application:
Procedure
- Determine whether you want the rollout update process to stop or pause the affected
application servers.
- If you want the rollout update process to stop a server before it performs an application
update, go to step 5.
- If you want the rollout process to pause a server before it performs an application update, go
to step 2. Steps 2, 3, and 4 are configuration changes that enable the rollout update process to
pause and resume servers during an application update. You have to make these changes only once.
Note: These configuration changes involve setting com.ibm.websphere.zos.mvsservices.enable
and com.ibm.websphere.zos.rollout.pauseresume to true. These custom
properties PAUSE/RESUME instead of STOP/START servers on z/OS. Setting these properties to
true avoids the overhead of stopping and starting servers during the rollout
update process. When active requests are pending during the rollout update process, these active
requests are stopped. You can use the com.ibm.websphere.zos.rollout.pause.waitTimeout custom
property to decide how long the deployment manager waits for a server to pause.
-
Add the com.ibm.websphere.zos.mvsservices.enable,
com.ibm.websphere.zos.rollout.pauseresume, and
com.ibm.websphere.zos.rollout.pause.waitTimeout custom properties to the node agent settings
in the master configuration repository on the deployment manager server.
These properties must be added to the settings for all of the node agents on which you want to
automatically start the MVSServices MBean.
-
In the administrative console, click node_agent_name > Administration Services > Custom
Properties > New
-
Enter com.ibm.websphere.zos.mvsservices.enable in the Name field, and true in the
Value field.
-
Click Ok .
-
Click New .
-
Enter com.ibm.websphere.zos.rollout.pauseresume in the Name field, and true in
the Value field.
-
Click Ok .
-
Click New.
-
Enter com.ibm.websphere.zos.rollout.pause.waitTimeout in the Name field, and the wait
time in seconds in the Value field. The default is 10 seconds.
-
Click Ok.
-
Repeat these steps for any other node agents on which you want to automatically start the
MVSServices MBean.
- Click Save to save your changes directly to the master configuration.
After you add the com.ibm.websphere.zos.rollout.pauseresume
custom property and
set it to true, any future application roll outs on this node are accomplished by pausing a
listener for the application server, rather than stopping that application server.
If the custom property com.ibm.websphere.zos.rollout.pauseresume
is set to true,
but the MVSServices MBean is not running on the configured node, the application servers on that
node do not pause, and are not updated during the application update process.
Messages are displayed on the MVS™ Console when an application server is paused or resumed similar to the
messages that are displayed when an application server is stopped or started.
- Restart the node agent.
When you restart the node agent, the MVSServices MBean
automatically starts.
- Update the application configuration repository in the master on the deployment manager
server.
Results
You are ready to start the rollout update process for an application that you need to
update.
What to do next
To start the rollout update process, in the administrative console, click Applications >
Enterprise Applications, select the application to update, and click Rollout Update.
Avoid trouble: The application that you select must reside on at least
one member of a cluster.
This function automatically stops or pauses the server, updates the application, and then starts
or resumes the server. Nodes are processed one at a time, so only the server that resides on the
node that is being processed is affected. The servers on the other nodes continue to process work.
Eventually all of the nodes and servers are updated.
The update process is complete when the updated version of the application is running on all of
the LPARs in the cluster.