Rolling Upgrade is the process of upgrading a running WebLogic Server cluster with a patch, maintenance pack, or minor release without shutting down the entire cluster or domain. During the rolling upgrade of a cluster, each server in the cluster is individually upgraded and restarted while the other servers in the cluster continue to host your application.
Prior to the WebLogic Server 9.2 release, to upgrade a cluster, you had to either shutdown the entire domain, or install the upgraded server version on a parallel domain on additional hardware and use a load balancer to transfer load from the old domain to the new domain. The rolling upgrade process minimizes downtime and allows you to install a patch, maintenance pack, or minor release while the domain is still running.
This document provides information about the following topics:
Support for rolling upgrade was available starting with WebLogic Server 9.2. The scope of rolling upgrade support encompasses installation of patches and maintenance packs as they are made available for WebLogic Server 10.0.
Rolling upgrade is most applicable to a cluster of WebLogic Server instances, however, you can also install updates to a domain of Managed Servers that are not in a cluster. This documentation focuses on installing upgrades in a cluster.
You can also uninstall a patch, maintenance pack, or minor release in a rolling fashion.
You can still upgrade to the latest patch using other strategies including bringing applications down in order to perform WebLogic Server upgrades, and restarting applications after WebLogic Server upgrades are complete. The rolling upgrade process provides you with an option of upgrading a running WebLogic Server cluster without shutting down the entire cluster or domain.
Before you begin the upgrade process, make sure that you take any necessary precautions such as:
The rolling upgrade process includes stopping the Administration Server, installing the upgrade, restarting the Administration Server, and then doing the same for each managed server in the cluster. See the following sections for more information:
Before you install the WebLogic Server update on a server, you must first shut down the server. Prior to server shutdown, and depending on your environment, you may need to first stop load balancers or Web Servers from sending requests or traffic to the server, complete any pending processes and then gracefully shut down the server.
You can shut down a Managed Server from the command line, in a WLST script, or from the Administration Console.
From the command line, you can gracefully shut down the server using the
Graceful Shutdown command. This command waits for all the in-process work to be completed before shutting down the server or cluster.
For information about using the
Graceful Shutdown command, see in WebLogic Scripting Tool (WLST). For information about how to shut down the Managed Server from the Console, see in Administration Console Online Help.
shutdown() command, make sure that you are connected to the Managed server instance that you want to stop. For information about using WLST to shut down servers, see in WebLogic Scripting Tool.
After you stop the running server on your machine, install the maintenance upgrade. For more information, seein Installing Maintenance Updates and Service Packs.
There are multiple methods for installing the patch, maintenance pack, or minor release. The following sections provide information about each of these options.
You can use the Smart Update feature to periodically check for available software updates. When you start Smart Update, it checks the version numbers of the products installed (associated with the current BEA Home directory), and then connects to the BEA Web site to check for available service packs. For more information about installing using Smart Update, see Installing Maintenance Updates and Service Packs.
In most cases, the maintenance upgrade can be distributed and installed using a script. You can create a mechanism for replicating a specific maintenance level of a BEA product that is installed on multiple machines. This capability is especially valuable in production environments, in which the distribution of software updates to machines must be implemented in a controlled, reliable, and reproducible manner.
You can use the Smart Update
bsu command, which you can use to apply patches, interactively or via script, that have been downloaded into a patch download directory. For more information, see in Installing Maintenance Updates and Service Packs.
Silent-mode installation is a way of setting installation configurations only once and then using those configurations to duplicate the installation on many machines. During installation in silent mode, the installation program reads the settings for your configuration from an XML file that you create prior to beginning the installation. The installation program does not display any configuration options during the installation process. Silent installation applies only to maintenance packs and minor version installation. For more information, seein BEA Products Installation Guide.
After you install the maintenance upgrade, you may need to modify start scripts before you restart your server. For more information see,in Installing Maintenance Updates and Service Packs. In addition, other post install tasks that you need to do will vary depending on your environment and the type of maintenance that you installed.
For an overview of methods for starting and stopping server instances, seein Managing Server Startup and Shutdown.
If required, you may need to reconfigure your Web server or load balancer after the server is started so that requests are again sent to the server.
A patch is a file containing a fix or a small number of fixes that you can install using Smart Update. A patch is typically created to fix a software defect. A patch can be installed using Smart Update (recommended) or by referencing the patch at the beginning of the classpath.
A maintenance pack is a group of fixes combined into one file. Maintenance packs can be installed using Smart Update or by downloading an installer from the support Web site. Both maintenance packs and patches are applied to an existing installation.
While the WebLogic Server domain is running, follow these steps:
|Note:||You can also modify the start scripts using Smart Update to automate the restart process. For more information, seein Installing Maintenance Updates and Service Packs.|
You have now completed the upgrade process.
A minor version is a new release that includes fixes and new features. A minor release is installed in a completely new directory. Existing domains from the same release family can be run using the new minor release. WebLogic Server WebLogic Server 9.1 and WebLogic Server 9.2 are existing examples of minor versions of WebLogic Server 9.x.
While the WebLogic Server domain is running, follow these steps:
You can uninstall a patch, maintenance pack, or minor release without shutting down the entire cluster or domain. The following sections provide more information.
At times you may want to uninstall a maintenance upgrade. You can use Smart Update to revert your system installation to an earlier version of the release. For more information, seein Installing Maintenance Updates and Service Packs.
The procedure for uninstalling a patch or maintenance pack is in the opposite order of the rolling upgrade:
The applied patch or maintenance pack is now uninstalled.
For information about uninstalling a minor release, seein BEA Products Installation Guide.
The procedure is in the opposite order of the rolling upgrade:
The new version of WebLogic Server is now uninstalled.
During the upgrade process, certain installed files may need to be replaced. However, because the WebLogic Server instance uses these installed files while it is running, the files can be replaced during the upgrade process only after you shutdown the server instance. If multiple managed servers share the same installation of WebLogic Server, all instances that use the set of files must be shut down and upgraded at the same time. In support of rolling upgrade, BEA recommends that each managed server have its own installation of WebLogic Server.
You should not make configuration changes during the upgrade process until all the servers in the cluster have been upgraded. This is especially true for new configuration options. Servers will silently ignore settings that they do not understand, and the local configuration file may not be updated properly. Also, using new configuration options may prohibit the capability of uninstalling a maintenance upgrade in a rolling fashion.