Apache httpd in front of Tomcat on a local dev machine

This page explains how to set up an Apache HTTP Server (httpd) in front of Tomcat on a local machine for development purposes. This page is not intended as a guide for a system administrator to set up a production environment.

At the end you can access the Magnolia contexts with different domains which both serve from root. This kind of setup may help testing multisite scenarios during local development to emulate a production environment scenario.

Domains and /etc/hosts

This is an overview of the the multisite setup:

Note that we use only one domain - a subdomain of the "main domain" - to access the author instance (which is recommended practice).

To enable this without DNS, add the following line to your /etc/hosts file:

127.0.0.1		author.best-comics.net www.best-comics.net www.best-vinyl.net

Apache setup

Make sure you have a working Apache on your local machine. 

Helpful Apache commands

Whenever you change Apache configuration files, you have to restart the httpd process.

Restart the process

sudo apachectl restart

Check the configuration

apachectl configtest

Enable mod_proxy, proxy_ajp_module

Make sure your Apache has the modules mod_proxy and proxy_ajp_module enabled.

Check the /etc/apache2/httpd.conf file and make sure the following lines are not commented:

LoadModule proxy_module libexec/apache2/mod_proxy.so
# more line in between ...
LoadModule proxy_ajp_module libexec/apache2/mod_proxy_ajp.so

On a different OS, the path and suffix of the modules may be different. If you edit the file, you must restart Apache.

Enable vhosts

We use virtual hosts configuration in this setup. Make sure vhosts are enabled. Check the  /etc/apache2/httpd.conf file and ensure the line with the include directive is not commented:

# Virtual hosts
Include /private/etc/apache2/extra/httpd-vhosts.conf

Define virtual hosts

If vhosts is properly enabled, edit the /etc/apache2/extra/httpd-vhosts.conf file and add something similar to this:

<VirtualHost *:80>
    ServerName author.best-comics.net
#    ProxyPass / http://localhost:8080/
#    ProxyPassReverse / http://localhost:8080/
	ProxyPass / ajp://localhost:8009/
    ProxyPassReverse / ajp://localhost:8009/

    ErrorLog "/private/var/log/apache2/projekt.local-error_log"
    CustomLog "/private/var/log/apache2/projekt.local-access_log" common    
</VirtualHost>

Using ajp

See lines 3, 4 above which are commented: At first sight one may think that these ProxyPass rules should be sufficient. However, they're not. Some things will work, but especially the multisite setup won't do what we expect .

Since we use ajp - the ajp connector must be configured in the Tomcat server.xml - which is the case in the default server.xml which is provided by a Magnolia bundle. In the server.xml of your Tomcat you should find an entry as this:

<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" /> 

Redirecting to Tomcat root

The apache redirect points to the Tomcat root context (see lines 5, 6 in the excerpt from httpd-vhosts.conf shown above).

Redirecting to ajp://localhost:8009/magnoliaAuthor - would work, but again, only partially. (Try it out, if you want to have fun.) Web resources would not load and redirections done by Magnolia would be incorrect. 

So, since the apache redirect points to the Tomcat root context, we must make sure that the webapp magnoliaAuthor is served from the root context. This needs a few modifications on Tomcat (see below).

Tomcat adjustments to serve one context from root

I guess there are different possible solutions to serve a Magnolia instance from Tomcat root context. Here comes one:

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />


  <GlobalNamingResources>
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>


  <Service name="Catalina">

    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />


	<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />

    <Engine name="Catalina" defaultHost="localhost">

      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
               resourceName="UserDatabase"/>
      </Realm>

      <Host name="localhost"  appBase="webapps" unpackWARs="true" autoDeploy="true">
		<!-- server author from root -->  
		<Context path="" docBase="magnoliaAuthor" />
    
	    <Valve className="org.apache.catalina.valves.AccessLogValve" 
			directory="logs" 
			prefix="localhost_access_log" 
			suffix=".txt" pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>
	  
    </Engine>
	
  </Service>
  
</Server>

It works. However, since now we have only one context served from root. 

Usage in a production environment

In a productive environment, you probably have 2 hosts / servers in different networks, in which one server contains one Tomcat serving a single instance. If this is true, the setup described above is feasible.

Serve both contexts from root from localhost

The following, extended setup allows to run and access both Magnolia instances from one Tomcat instance. 

 Once again, this is a not required setup for productive environments, but it works fine on a local development machine.

These is the demanded setup:

Keep in mind that we already have defined redirects to localhost  for these three domains  (in the /etc/hosts file).

Virtual hosts configuration

In summary we need three virtual hosts on Apache - here is the modified httpd-vhosts.conf with one virtual host for the author instance and two for the public instances:

<VirtualHost *:80>
    ServerName author.best-comics.net
	ProxyPass / ajp://localhost:8009/
    ProxyPassReverse / ajp://localhost:8009/
</VirtualHost>

<VirtualHost *:80>
    ServerName www.best-comics.net
	ProxyPass / ajp://localhost:8010/
    ProxyPassReverse / ajp://localhost:8010/
</VirtualHost>

<VirtualHost *:80>
    ServerName www.best-vinyl.net
	ProxyPass / ajp://localhost:8010/
    ProxyPassReverse / ajp://localhost:8010/
</VirtualHost>

• Lines 3-4: author.best-comics.net redirects to localhost on port 8080 => webapp magnoliaAuthor
• Lines 9-10, 15-16: www.best-comics.net and www.best-vinyl.net are redirected to localhost on port 8081 => => webapp magnoliaPublic
• The lines configuring the log files of the virtual hosts have been removed to keep this configuration excerpt small.

Tomcat adjustments

As mentioned above, one Tomcat host cannot serve two contexts from root. 

We achieve this by the the following:

• Define two <Service> sections in the server.xml.
• Each <Service>:
  
  • Has  <Connector>s with distinct ports.
    • AJP connector
    • HTTP connector *
  • Serves from its own webapps directory.
  • Defines one host which wraps exactly one context to be served from root.

*) Actually the AJP connector would be sufficient to use tomcat via apache. However, if you also keep the HTTP connector, you can access tomcat also directly. And we also will use the HTTP connector for JCR activations from author to public context.

webapps directory

We assume that the bundle has already been started once and that both webapps have been properly installed.

This is the adapted Tomcat directory structure:

├── bin
├── conf
├── lib
├── webapps
│   ├── ROOT
│   └── magnoliaAuthor
└── webapps2
    └── magnoliaPublic

• Create the folder webapps2.
• Move the webapp magnoliaPublic to webapps2.
• You may want delete the webapp ROOT, you won't be able to access it anymore.

server.xml

This is the server.xml:

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN">
  <Listener className="org.apache.catalina.startup.VersionLoggerListener" />
  <Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
  <Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
  <Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
  <Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />


  <GlobalNamingResources>
    <Resource name="UserDatabase" auth="Container"
              type="org.apache.catalina.UserDatabase"
              description="User database that can be updated and saved"
              factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
              pathname="conf/tomcat-users.xml" />
  </GlobalNamingResources>


  <Service name="Catalina">
    <Connector port="8080" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8443" />
	<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
    <Engine name="Catalina" defaultHost="localhost">
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>
      </Realm>
      <Host name="localhost"  appBase="webapps" unpackWARs="true" autoDeploy="true">
		<Context path="" docBase="magnoliaAuthor" />
	    <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs" prefix="localhost_access_log" suffix=".txt" pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>
    </Engine>
  </Service>
  
  <Service name="Catalina2">
    <Connector port="8081" protocol="HTTP/1.1"
               connectionTimeout="20000"
               redirectPort="8444" />
	<Connector port="8010" enableLookups="false" redirectPort="8444" protocol="AJP/1.3" />
    <Engine name="Catalina2" defaultHost="localhost">
      <Realm className="org.apache.catalina.realm.LockOutRealm">
        <Realm className="org.apache.catalina.realm.UserDatabaseRealm" resourceName="UserDatabase"/>
      </Realm>
      <Host name="localhost"  appBase="webapps2" unpackWARs="true" autoDeploy="true">
		<Context path="" docBase="magnoliaPublic" />
	    <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs" prefix="localhost_access_log" suffix=".txt" pattern="%h %l %u %t &quot;%r&quot; %s %b" />
      </Host>
    </Engine>
  </Service>
  
  
  
</Server>

• There are two <Service> sections, their name attributes have different values.
• Every <Service> has its own <Connector>s with distinct ports
• Each connector must have its own distinct ports on the attributes port and redirectPort.
• The port of the AJP-<Connector> is the same port to which we redirect on the Apache virtual host configuration.

Final adjustments on the Magnolia instance

Adjust the subscriber for content activation

To ensure content activation still works, you have to adjust the property /server/activation/subscribers/magnoliaPublic8080@URL:

 Note that the activation is using the HTTP connector.