Why a newer JRE is important?
AppMon installations (Server, Collector, Client,...) are always shipped with a running an Oracle Java 8 JRE. We always used the most recent version for all of our AppMon releases, to guarantee a stable and reliable deployment. Over time it can happen, that the shipped JRE is outdated. Why this can be is important? Newer versions always containing security updates and bugfixes. Thus, it makes sense to keep the JRE updated, to avoid security vulnerabilities and fix avoid other known problems. This article describes:
When you install Dynatrace AppMon you will get the follwoing JREs on Windows and Linux:
For collectors running on other platforms we don't ship a JRE. The JRE must be provided by the customer. This article focuses on how to update the shipped JREs.
Which JREs are supported
Until now, AppMon only supported the Oracle JREs. Starting with OpenJDK Update 192 we also support OpenJDK. This is important as OpenJDK 8 will ship security updates longer than Oracle.
For AppMon 7.1 we only offer the JRE that comes with the installer. Newer Updates have to be provided and deployed by the customer. We support the following runtimes:
No newer major Java versions (like 9, 10, 11,...) are/will be supported
Starting with AppMon 7.2, Dynatrace offers JRE update packs that provides you with a recent Java runtime, including security fixes. There is no need (possibility) to deploy a custom runtime.
So we basically support all JREs that we offer through our JRE update packs. No other JREs are supported. In practice we provide:
How to update the JRE
For upgrading the runtime of any AppMon installation, please follow these steps (so those steps have to be done for any AppMon Installation being it a Full, Server, Collector or Client install):
1. Make sure you have a supported JDK somewhere (Oracle JDK or OpenJDK - really use a JDK and not a plain JRE as we will need the tools.jar). We will call this directory NEW_JRE_HOME
Windows: e.g. C:\%program_files%\java\jdk1.7.0_<update>
2. Shut down the components where you want to update the JRE
3. Rename directory <DT_INSTALL_DIR>/jre to <DT_INSTALL_DIR>/jre.orig
<DT_INSTALL_DIR> is the location of the AppMon installation
4. Copy a the JRE folder from <NEW_JRE_HOME> to the directory <DT_INSTALL_DIR>/jre
Windows: e.g. Copy contents of "C:\%program_files%\java\jdk1.8.0_<update>\jre" to folder "C:\%program_files%\dynaTrace\dynaTrace 7.1\jre"
5. Copy the tools.jar file from <NEW_JRE_HOME>/lib to <DT_INSTALL_DIR>/jre/lib
Windows: e.g. Copy file "C:\%program_files%\java\jdk1.8.0_<update>\lib\tools.jar" to folder "C:\%program_files%\dynaTrace\dynaTrace 7.1\jre\lib"
6. Startup the affected components and check if everything starts as expected
7. If everything is running fine, delete the backup directory created in step 3. In case of any problems delete the directory <DT_INSTALL_DIR>/jre and rename <DT_INSTALL_DIR>/jre.orig to <DT_INSTALL_DIR>/jre
As already mentioned we have a new approach of shipping Java updates to our customers. A detailed description can be found in the AppMon documentation (https://www.dynatrace.com/support/doc/appmon/installation/product-updates/jre-update/).