Tomcat behind Apache using ajp for Spring Boot application

Question

I've been trying to configure Apache web server with a Spring Boot app that uses embedded Tomcat. Before Spring Boot I used to create an ajp.conf file like:

<VirtualHost *:80>
   ServerName localhost
   <Proxy *>
      AddDefaultCharset Off
      Order deny,allow
      Allow from all
   </Proxy>

   ProxyPass /app ajp://localhost:8009/app
   ProxyPassReverse /app ajp://localhost:8009/app

 </VirtualHost>

And include in the httpd.conf file like

Include /opt/lampp/apache2/conf/ajp.conf

And in the Tomcat's server.xml file, I used to configure it to listen to port 8009

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" connectionTimeout="5000"

This setup works. But, now with Spring Boot I am trying to achieve something similar with an embedded tomcat. I read Spring Boot Documentation here and added the following propertied on my application.yml file:

server:
    port: 8080
    tomcat:
        remote_ip_header: x-forwarded-for
        protocol_header: x-forwarded-proto

My ajp.conf file looks like so:

<VirtualHost *:80>
   ServerName localhost
   <Proxy *>
      AddDefaultCharset Off
      Order deny,allow
      Allow from all
   </Proxy>

   ProxyPass /app ajp://localhost:8009/
   ProxyPassReverse /app ajp://localhost:8009/

 </VirtualHost>

I have my spring boot tomcat configuration class as

@Configuration
public class TomcatConfiguration {

private final Logger log = LoggerFactory.getLogger(TomcatConfiguration.class);

@Bean
public EmbeddedServletContainerFactory servletContainer() {
    TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory();
    tomcat.addAdditionalTomcatConnectors(createConnector());
    tomcat.addContextValves(createRemoteIpValves());
    return tomcat;
}

private RemoteIpValve createRemoteIpValves(){
    RemoteIpValve remoteIpValve = new RemoteIpValve();
    remoteIpValve.setRemoteIpHeader("x-forwarded-for");
    remoteIpValve.setProtocolHeader("x-forwarded-protocol");
    return remoteIpValve;
}

private Connector createConnector() {
    Connector connector = new Connector("org.apache.coyote.http11.Http11NioProtocol");
    Http11NioProtocol protocol = (Http11NioProtocol) connector.getProtocolHandler();
    connector.setScheme("ajp");
    connector.setProtocol("AJP/1.3");
    connector.setRedirectPort(8443);
    //connector.setSecure(true);
    connector.setPort(8009);
    return connector;
}

On my apache error logs I see:

AH01080: ajp_msg_check_header() got bad signature 4854
[proxy_ajp:error] [pid 24073] AH01031: ajp_ilink_receive() received bad header
[proxy_ajp:error] ajp_read_header: ajp_ilink_receive failed
[proxy_ajp:error] (120007)APR does not understand this error code: [client xx.xx.xx.xx:60916] AH00878: read response failed from (null) (*)

Not sure what's going on here. I searched a lot online, but could not find a good documentation on how to serve tomcat behind apache with spring boot apps. Eventually, I would like to load balance multiple tomcat instances too.

Answer 1

Deduced from the comments above:

@Configuration
public class TomcatAjpConfig {

@Bean
@SuppressWarnings("static-method")
public EmbeddedServletContainerFactory servletContainer() {
    TomcatEmbeddedServletContainerFactory tomcat = new TomcatEmbeddedServletContainerFactory();
    tomcat.addAdditionalTomcatConnectors(createConnector());
    tomcat.addContextValves(createRemoteIpValves());
    return tomcat;
}

private static RemoteIpValve createRemoteIpValves() {
    RemoteIpValve remoteIpValve = new RemoteIpValve();
    remoteIpValve.setRemoteIpHeader("x-forwarded-for");
    remoteIpValve.setProtocolHeader("x-forwarded-proto");
    return remoteIpValve;
}

private static Connector createConnector() {
    Connector connector = new Connector("AJP/1.3");
    connector.setPort(8009);
    return connector;
}

}

Answer 2

Had a similar problem but with HTTP-Proxy. After some debugging of Spring Boot 1.3 I found the following solution. It should be similar for the AJP Proxy.

1. You have to setup the headers on your Apache proxy:

<VirtualHost *:443>
    ServerName www.myapp.org
    ProxyPass / http://127.0.0.1:8080/
    RequestHeader set X-Forwarded-Proto https
    RequestHeader set X-Forwarded-Port 443
    ProxyPreserveHost On
    ... (SSL directives omitted for readability)
</VirtualHost>

2. You have to tell your Spring Boot app to use these headers. So put the following line in your application.properties (or any other place where Spring Boots understands properties):

server.use-forward-headers=true

If you do these two things correctly, every redirect your application sends will not go to http://127.0.0.1:8080/[path] but automatically to https://www.myapp.com/[path]

Update 1. The documentation about this topic is here. You should read it at least to be aware of the property server.tomcat.internal-proxies which defines the range of IP-addresses for proxy servers that can be trusted.