Tomcat Virtual Hosts

Remarks#

Host Manager is a web application inside of Tomcat that creates/removes Virtual Hosts within Tomcat.

A Virtual Host allows you to define multiple hostnames on a single server, so you can use the same server to handles requests to, for example, ren.myserver.com and stimpy.myserver.com.

Unfortunately documentation on the GUI side of the Host Manager doesn’t appear to exist, but documentation on configuring the virtual hosts manually in context.xml is here:

https://tomcat.apache.org/tomcat-7.0-doc/virtual-hosting-howto.html.

The full explanation of the Host parameters you can find here:

https://tomcat.apache.org/tomcat-7.0-doc/config/host.html.

_{Adapted from my answer: https://stackoverflow.com/a/26248511/6340}

Tomcat Host Manager Web Application

Tomcat’s Host Manager application by default is located at https://localhost:8080/host-manager, but is not accessible until a user is given permission in the conf/tomcat-users.xml file. The file needs to have:

A manager-gui role
A user with this role

For example:

<tomcat-users>
    ...
    <role rolename="manager-gui"/>
    ....
    <user username="host-admin" password="secretPassword" roles="manager-gui"/>
</tomcat-users>

Adding a Virtual Host via the Tomcat Host Manager Web Application

Once you have access to the host-manager, the GUI will let you add a virtual host.

Note: In Tomcat 7 and 8, adding a virtual host via the GUI does not write the vhost to config files. You will need to manually edit the server.xml file to have the vhost available after a restart. See https://tomcat.apache.org/tomcat-7.0-doc/virtual-hosting-howto.html for further info on the <Host> tag in server.xml

At a minimum you need the Name and App Base fields defined. Tomcat will then create the following directories:

{CATALINA_HOME}\conf\Catalina\{Name}
{CATALINA_HOME}\{App Base}

App Base will be where web applications will be deployed to the virtual host. Can be relative or absolute.
Name is usually the fully-qualified domain name (e.g. ren.myserver.com)
Alias can be used to extend the Name also where two addresses should resolve to the same host (e.g. www.ren.myserver.com). Note that this needs to be reflected in DNS records.

The checkboxes are as follows:

Auto Deploy: Automatically redeploy applications placed into App Base. Dangerous for Production environments!
Deploy On Startup: Automatically boot up applications under App Base when Tomcat starts
Deploy XML: Determines whether to parse the application’s /META-INF/context.xml
Unpack WARs: Unpack WAR files placed or uploaded to the App Base, as opposed to running them directly from the WAR.
Tomcat 8 Copy XML: Copy an application’s META-INF/context.xml to the App Base/XML Base on deployment, and use that exclusively, regardless of whether the application is updated. Irrelevant if Deploy XML is false.
Manager App: Add the manager application to the Virtual Host (Useful for controlling the applications you might have underneath ren.myserver.com)

_{Adapted from my answer: https://stackoverflow.com/a/26248511/6340}

Adding a Virtual Host to server.xml

Once a virtual host has been added via the web application, directories will exist at:

{CATALINA_HOME}\conf\Catalina\{Name}
{CATALINA_HOME}\{App Base}

To persist the virtual host after a restart, the server.xml file must be updated with the configuration. A Host element needs to be added inside the Engine element, similar to this:

<Engine name="Catalina" ...>
  ...
  <Host name="my-virtual-app" appBase="virtualApp" autoDeploy="true" unpackWARs="true" ... />
</Engine>

The attributes in the Host element should reflect the selections made in the host manager GUI (see the Host documentation for details), but can be changed. Note that the Manager App option in the GUI does not correspond to any Host attribute.