One single balancer-manager page for multiple virtual hosts

Question

We're using currently an Apache 2.4 as load-balancer for a multi-master-cluster of three Tomcats-Servers. We can access the internal IP-Address of this load-balancer with an web-browser and change the settings on the fly (e.g. http://xx.xx.xx.xx/balancer-manager). This works and we're pretty fine with this.

Enabled modules:

• proxy.load (proxy.conf used to configure)
• proxy_ajp.load
• proxy_balancer.load (proxy_balancer.conf used to configure)

But now we will host several (three in this setup) virtual hosts on this Apache, each representing a cluster of three Tomcats itself. Each is accessiable via an URL like http://customer.company.tld/app/ui). So the path is the same for each cluster! Now we're facing two problems:

• The page balancer-manager is only reachable via it's virtual host. Therefore we have to access the balancer-manager via random choosen internal hostname (added to ServerAlias) and add this hostname also into the /etc/hosts off our internal computers to be be able to use it.
• Furthermore we have to do this for each virtual-host (~cluster). But we want a single page balancer-manager which presents all virtual-hosts and the cluster behind.

Here some sample configuration:
/etc/apache2/site-enabled/foo # we have actually three of them: foo, bar, baz

<VirtualHost *:80> ServerAdmin webmaster@localhost ServerName customer-foo.company.tld ServerAlias customer-foo-balancer customer-foo.company.tld www.customer-foo.company.tld DocumentRoot /var/www <Directory /> Options FollowSymLinks AllowOverride None Order allow,deny deny from all </Directory> <Directory /var/app/app_static> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> <Directory /var/www/app_static_res> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> # load balancer <Location /balancer-manager> SetHandler balancer-manager Order deny,allow Deny from all # allows for internal access Allow from 127.0.0.1 ::1 10.1.21.81 10.1.4.9 Satisfy all </Location> ProxyRequests Off ProxyVia Off ProxyPreserveHost On <Proxy balancer://htg> ProxySet failonstatus=503 BalancerMember ajp://10.171.23.120:8010/app lbset=0 route=foo001 loadfactor=40 BalancerMember ajp://10.171.23.121:8010/app lbset=0 route=foo002 loadfactor=40 BalancerMember ajp://10.171.23.122:8010/app lbset=0 route=foo003 loadfactor=20 </Proxy> <Proxy balancer://htgservice> ProxySet failonstatus=503 BalancerMember ajp://10.171.23.120:8011/wcs_service route=foo001 loadfactor=40 BalancerMember ajp://10.171.23.121:8011/wcs_service route=foo002 loadfactor=40 BalancerMember ajp://10.171.23.122:8011/wcs_service route=foo003 loadfactor=20 </Proxy> ProxyPass /app balancer://foo stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On ProxyPassReverse /app balancer://foo ProxyPass /app_service balancer://fooservice stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On ProxyPassReverse /app_service balancer://fooservice LogLevel warn ErrorLog ${APACHE_LOG_DIR}/error.log CustomLog ${APACHE_LOG_DIR}/access.log combined </VirtualHost> 

In the past we configured the balancing inside the distinct files proxy.conf and proxy_balancer.conf, which should allow for accessing via the internal IP and show up all clusters and cluster-members on a single page. But this won't work anymore, the configuration for proxies seem to accept only paths (e.g. app and app_service) not URLs or hostnames. We can't and won't change the paths. Therefore we moved the proxy-configuration inside the virtual hosts.

Thanks for your help!

Answer 1

What about splitting your config. Put your balancer definition outside any virtual host and remove the context:

 <Proxy balancer://htg> ProxySet failonstatus=503 BalancerMember ajp://10.171.23.120:8010 lbset=0 route=foo001 loadfactor=40 BalancerMember ajp://10.171.23.121:8010 lbset=0 route=foo002 loadfactor=40 BalancerMember ajp://10.171.23.122:8010 lbset=0 route=foo003 loadfactor=20 </Proxy> <Proxy balancer://htgservice> ProxySet failonstatus=503 BalancerMember ajp://10.171.23.120:8011 route=foo001 loadfactor=40 BalancerMember ajp://10.171.23.121:8011 route=foo002 loadfactor=40 BalancerMember ajp://10.171.23.122:8011 route=foo003 loadfactor=20 </Proxy> 

In your vhosts reference these balancers:

ProxyPass /app balancer://htg/app stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On ProxyPassReverse /app balancer://htg/app ProxyPass /app_service balancer://htgservice/wtg_service stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On ProxyPassReverse /app_service balancer://htgservice/wtg_service 

To access your balancer-manager, create an extra management vhost with <Location /balancer-manager> in it.

This way, you have one place where all your balancers are defined and one vhost to access the balancer-manager which shows you all your balncers.

Answer 2

Thank you Christian! The solution of Christian is correct!

Basically you have to put ProxyPass and ProxyPassReverse inside the configuration for the Virtual-Hosts, and define the Proxy-Directive in the proxy.conf. As Christian already stated in his own comments, it is required use the ProxySet-Directive inside the Proxy-Directive to configure the StickySessions - it won't work with ProxyPass. Bellow is a short, but complete, example:

Sample VirtualHost (one for foo, bar, baz):

<VirtualHost *:80> ServerAdmin webmaster@localhost ServerName customer-foo.company.tld ServerAlias customer-foo-balancer customer-foo.company.tld www.customer-foo.company.tld DocumentRoot /var/www/foo <Directory /> Options FollowSymLinks AllowOverride None Order allow,deny deny from all </Directory> <Directory /var/www/foo/wcs_static> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> <Directory /var/www/foo/wcs_static_res> Options Indexes FollowSymLinks MultiViews AllowOverride All Order allow,deny allow from all </Directory> # maintenance RewriteEngine On RewriteCond %{DOCUMENT_ROOT}/wcs_static_res/maintenance.html -f RewriteCond %{REQUEST_FILENAME} !/wcs_static_res/maintenance.html RewriteCond %{REQUEST_FILENAME} !/wcs_static_res/maintenance-time.png RewriteCond %{REMOTE_HOST} !^10\.1\.0\.203 RewriteRule ^.*$ /wcs_static_res/maintenance.html [L] # redirect, SSL itself is handled by another server in front of this loadbalancer RedirectMatch (.*)/$ https://customer-foo.company.tld/wcs/ui # load balancer # web-frontend ProxyPass /wcs balancer://foo # stickysession can't be set with ProxyPass in this case, see proxy.conf ProxyPassReverse /wcs balancer://foo # standalone-clients ProxyPass /wcs_service balancer://fooservice ProxyPassReverse /wcs_service balancer://fooservice # logging LogLevel warn ErrorLog ${APACHE_LOG_DIR}/foo_error.log CustomLog ${APACHE_LOG_DIR}/foo_access.log combined </VirtualHost> 

proxy.conf (there is only this one):

<IfModule mod_proxy.c> ProxyRequests Off ProxyVia Off ProxyPreserveHost On <Proxy balancer://foo> # stickysessions must be defined here ProxySet failonstatus=503 stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On BalancerMember ajp://10.171.23.120:8010/wcs lbset=0 route=foo001 loadfactor=40 BalancerMember ajp://10.171.23.121:8010/wcs lbset=0 route=foo002 loadfactor=40 BalancerMember ajp://10.171.23.122:8010/wcs lbset=0 route=foo003 loadfactor=20 </Proxy> <Proxy balancer://fooservice> ProxySet failonstatus=503 stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On BalancerMember ajp://10.171.23.120:8011/wcs_service route=foo001 loadfactor=40 BalancerMember ajp://10.171.23.121:8011/wcs_service route=foo002 loadfactor=40 BalancerMember ajp://10.171.23.122:8011/wcs_service route=foo003 loadfactor=20 </Proxy> <Proxy balancer://bar> ProxySet failonstatus=503 stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On BalancerMember ajp://10.171.21.110:8010/wcs lbset=0 route=bar001 loadfactor=40 BalancerMember ajp://10.171.21.111:8010/wcs lbset=0 route=bar002 loadfactor=40 BalancerMember ajp://10.171.21.112:8010/wcs lbset=0 route=bar003 loadfactor=20 </Proxy> <Proxy balancer://barservice> ProxySet failonstatus=503 stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On BalancerMember ajp://10.171.21.110:8011/wcs_service route=bar001 loadfactor=40 BalancerMember ajp://10.171.21.111:8011/wcs_service route=bar002 loadfactor=40 BalancerMember ajp://10.171.21.112:8011/wcs_service route=bar003 loadfactor=20 </Proxy> <Proxy balancer://baz> ProxySet failonstatus=503 stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On BalancerMember ajp://10.171.45.100:8010/wcs lbset=0 route=baz001 loadfactor=40 BalancerMember ajp://10.171.45.101:8010/wcs lbset=0 route=baz002 loadfactor=40 BalancerMember ajp://10.171.45.102:8010/wcs lbset=0 route=baz003 loadfactor=20 </Proxy> <Proxy balancer://bazservice> ProxySet failonstatus=503 stickysession=JSESSIONID|jsessionid nofailover=Off scolonpathdelim=On BalancerMember ajp://10.171.45.100:8011/wcs_service route=baz001 loadfactor=40 BalancerMember ajp://10.171.45.101:8011/wcs_service route=baz002 loadfactor=40 BalancerMember ajp://10.171.45.102:8011/wcs_service route=baz003 loadfactor=20 </Proxy> </IfModule> 

proxy_balancer.conf:

<IfModule mod_proxy_balancer.c> <IfModule mod_status.c> <Location /balancer-manager> SetHandler balancer-manager Order deny,allow Deny from all # store here your internal IPs for direct access Allow from 127.0.0.1 ::1 Satisfy all </Location> </IfModule> 

Now you can change the configuration through http://ipofloadbalancer.com/balancer-manager for all servers behind your proxy. No need to hack with /etc/hosts on the clients and the loadbalancer. Drawback, especially with the Apache 2.4, the interface gets quickly cluttered and you have to scroll much.