Apache HTTPD and Tomcat configuration

I run some application at linux server. It's quite simple installation but sometimes it's difficult for me to remember why it's configure in such way. This post helps me to understand current state. Hopefully it will be useful for someone else.

Server is just one linux box with CentOS. There are no dependencies to other nodes or services. It's really simple.

On server is installed Apache HTTPD service. Service could be started stopped via commands /etc/init.d/https {stop|start| ...}. Among others apache contains module mod_jk which is responsible for communication with AJP protocol load balancing and other stuff. Closer description of mod_jk could be found at http://tomcat.apache.org/connectors-doc/. The reason why I need Apache HTTPS in front of Tomcat server is that I need more tomcats for different hosted domains and Apache HTTPD server is used also for PHP. Connection between Apache HTTPD server and Tomcat servers is at following image.

Applications are also split between few linux system accounts. It's because of security.

Now let's look at configuration of Apache HTTPD:

<VirtualHost *:80>
   ServerName www.domain2.com 
   ServerAlias *.domain2.com
   ServerAlias *.domain3.com
   ErrorLog /var/log/httpd/domain2.com.err.log
   CustomLog /var/log/httpd/domain2.com.log combined

   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>
 
   ProxyPass / ajp://localhost:7001/
   ProxyPassReverse / ajp://localhost:7001/
</VirtualHost>


<VirtualHost *:80>
   ServerName www.domain1.com
   ServerAlias *domain1.com
   ErrorLog /var/log/httpd/domain1.com.err.log
   CustomLog /var/log/httpd/domain1.com.log combined

   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>
 
   ProxyPass / ajp://localhost:7005/
   ProxyPassReverse / ajp://localhost:7005/
</VirtualHost>

Finally there have to be some configuration at Tomcats side. Here is configuration from tomcat2 ./conf/server.xml file:

<Connector port="7001" protocol="AJP/1.3" redirectPort="8443" />

<Engine name="Catalina" defaultHost="www.domain2.com">

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

    <Host name="repo.domain2" appBase="domain/repo.domain2.com"
        unpackWARs="true" autoDeploy="true"
        xmlValidation="false" xmlNamespaceAware="false">
    </Host>

    <Host name="www.domain2.com" appBase="domain/www.domain2.com"
        unpackWARs="true" autoDeploy="true"
        xmlValidation="false" xmlNamespaceAware="false">
        <Alias>domain2.com</Alias>
    </Host>

    <Host name="www.domain3.com" appBase="domain/www.domain3.com"
        unpackWARs="true" autoDeploy="true"
        xmlValidation="false" xmlNamespaceAware="false">
        <Alias>domain2.com</Alias>
    </Host>

</Engine>

curl - GET single file

Curl is simple yet powerful tool for creating HTTP and FTP requests of all kind. I have permanent problem with simple getting file with curl and storing in to file system. This little post should remember it to me. Basically works like this:

curl -v --location --max-redirs 10 \
 --output install_1.3.0.sql \
 http://somesite.com/somefile.sql

One trick is to use --location which tell to curl to follow redirects until number of redirect reach value specified in --max-redirs. Second trick is to specify output file in --output. When output file is not specified retrieved data are send to console (STDOUT).