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 rollout
of these updates.
When setting 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 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 rollout 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 only have to make these
changes 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. Be aware that when active requests are pending during the
rollout update process, these active requests are stopped.
- Add the com.ibm.websphere.zos.mvsservices.enable and com.ibm.websphere.zos.rollout.pauseresume 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 .
- 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
rollouts 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 you select must reside
on at least one member of a cluster.
gotcha
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 residing on the node 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.