无法访问manager-gui tomcat8

Question

I have installed tomcat8 on Ubuntu 15.10 and I get the usual welcome screen when I go to:

http://myhost:8082/

(I reconfigured the port to 8082 in server.xml).

But I cannot access the manager gui at:

http://myhost:8082/manager/html

I have tried the following in the /etc/tomcat8/tomcat-users.xml file followed by a restart of tomcat8 with:

sudo /etc/init.d/tomcat8 restart

Here are the edits I have tried:

1)

 <role rolename="manager-gui"/>
 <user username="admin" password="12345" roles="manager-gui"/>

2)

<user username="user" password="password" roles="admin-gui,manager-gui" />

I have found other SO posts and blogs each describing new way so configure the users/roles but none of them work. Instead I keep getting:

cat catalina.out


INFO: Starting service Catalina
Apr 27, 2016 10:36:32 PM org.apache.catalina.core.StandardEngine startInternal
INFO: Starting Servlet Engine: Apache Tomcat/8.0.26 (Ubuntu)
Apr 27, 2016 10:36:32 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deploying web application directory /var/lib/tomcat8/webapps/ROOT
Apr 27, 2016 10:36:32 PM org.apache.catalina.core.StandardContext setPath
WARNING: A context path must either be an empty string or start with a '/' and do not end with a '/'. The path [/] does not meet these criteria and has been changed to []
Apr 27, 2016 10:36:34 PM org.apache.jasper.servlet.TldScanner scanJars
INFO: At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
Apr 27, 2016 10:37:36 PM org.apache.catalina.util.SessionIdGeneratorBase createSecureRandom
INFO: Creation of SecureRandom instance for session ID generation using [SHA1PRNG] took [61,847] milliseconds.
Apr 27, 2016 10:37:36 PM org.apache.catalina.startup.HostConfig deployDirectory
INFO: Deployment of web application directory /var/lib/tomcat8/webapps/ROOT has finished in 63,602 ms
Apr 27, 2016 10:37:36 PM org.apache.coyote.AbstractProtocol start
INFO: Starting ProtocolHandler ["http-nio-8082"]
Apr 27, 2016 10:37:36 PM org.apache.catalina.startup.Catalina start
INFO: Server startup in 63722 ms

Answer 1

Looks like you don't have the manager app installed at all. It's not installed with ubuntu's tomcat by default. In Ubuntu 14.04 there's a package tomcat7-admin - I'm assuming that you can probably find tomcat8-admin in 15.10 - check the result of aptitude search tomcat and validate the available packages, then sudo aptitude install tomcat8-admin.

When you install it, remember to protect it properly - you shouldn't have it available in a production system without explicitly limiting who has access to it (with more than just username/password)