How to increase maximum HTTP header size for Java Spring Boot app hosted in Azure App Service (deployed as.WAR)?

Question

We have a Java Spring Boot application hosted in an Azure App Service (Windows), and we need to increase the value of maxHttpHeaderSize on the Tomcat 9 server to probably around 32KB. I can't work out how we can influence the server settings to do this.

How can I override the maxHttpHeaderSize value for the Tomcat server in the Azure App Service?

Here are the "Stack settings" from the "Configuration" page for the App Service:

• Stack: Java
• Java version: Java 11
• Java minor version: Java 11 (auto-update)
• Java web server: Apache Tomcat 9.0
• Java web server version: Apache Tomcat 9.0 (auto-update)

We currently deploy the app via a DevOps pipeline that uploads a .WAR .

The reason that we need to increase the maximum header size is that we integrate with Azure AD for authentication, and it's adding large headers (due to quite a large number of user groups we think) which are tipping requests over the current limit for some users.

Any guidance is much appreciated. Thank you!

Answer 1

example, application.properties

server.max-http-header-size=10KB

Reference document https://docs.spring.io/spring-boot/docs/current/reference/html/application-properties.html#:~:text=server.max%2Dhttp%2Dheader%2Dsize