As far as access to the tomcat manager GUI is considered, there is no
role as "manager" to set in tomcat-users.xml.
you have to specify one of these roles.
You can find the role names in the web.xml file of the Manager web
application. The available roles are:
•manager-gui — Access to the HTML interface.
•manager-status — Access to the "Server Status" page
•manager-script — Access to the tools-friendly plain
text interface that is described in this document, and to the "Server
•manager-jmx — Access to JMX proxy interface and to
the "Server Status" page.
have a look into this link for further info,
I hope it helps, thanks.