Is Tomcat Clustering Supported?
Environment
- JBoss Enterprise Web Server (EWS)
- 2.x, 1.x,
- JBoss Web Servers (JWS)
- 7.x, 6.x, 5.x, 3.x, 2.x
- Red Hat Enterprise Linux (RHEL)
- 10.x, 9.x, 8.x, 7.x, 6.x
Issue
- Is the clustering capability that comes with tomcat supported (whether installed with EWS or via RPM)?
- Is HTTP session replication is supported in JWS tomcat?
Resolution
EWS / JWS 2.x and 3.x
Red Hat has no plans to support Tomcat clustering at this time because it is not deemed to be enterprise ready. Tomcat clustering is NOT supported with the EWS/JWS Tomcat distributions
Clustering was removed from the EWS version of Tomcat 6 and is deprecated in Tomcat 5. See EWS 1.0.2 Release Notes 1. It is also removed from EWS 2 per its release notes 2. If clustering is a requirement, we recommend using the Enterprise Application Platform (EAP) 3 instead.
JWS 5.x/6.x/7.x
Clustering function that is implemented in tomcat/lib/catalina-tribes.jar is no longer removed since JWS 5. However, Clustering is NOT tested and NOT supported on JWS5.x+ for now. To make this more clear and to avoid any security concerns appearing in clustering libraries (like CVE-2026-29146), clustering libraries are removed once again in JWS 6.2.3+.
RHEL
Under RHEL Entitlements, clustering was provided and supported previously in RHEL 5-7 Tomcat RPMs but only when fronted with the mod_proxy_balancer configuration4. RHEL 8/9 Tomcat RPMs are equivalent to and based on JWS 5+ so also do NOT contain tested and supported clustering functionality. Clustering libraries are removed from Tomcat RPMs (Content from redhat.atlassian.net is not included.RHEL-168577).
This content is not included.http://docs.redhat.com/docs/en-US/JBoss_Enterprise_Web_Server/1.0/html-single/Release_Notes_1.0.2/index.html#excluded_items
2: This content is not included.https://access.redhat.com/site/documentation/en-US/JBoss_Enterprise_Web_Server/2/html-single/2.0.0_Release_Notes/index.html#excluded_items
3: https://access.redhat.com/documentation/en-us/red_hat_jboss_enterprise_application_platform/7.4/html-single/configuration_guide/#clustering_modes
4: https://access.redhat.com/knowledge/node/222893
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