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50 lines
2.1 KiB
50 lines
2.1 KiB
10 years ago
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<b>Proxy HTTP requests in Apache 2.2 with mod_proxy and mod_balancer</b>
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You can actually use an Apache web server as a front web server to proxy
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specified requests to other web servers. For example to load balance your backend
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servers or to make a failover system in case of an failure. Yes, we are talking
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about high availability!
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<b>Simple</b>
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First enable the modules mod_proxy and mod_proxy_http. Now we can do a simple
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request forward. Of course we use a Debian system, so to enable the proxy modules
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we will do:
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a2enmod proxy proxy_http
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/etc/init.d/apache2 restart
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Now we can make use of the proxy capabilities of Apache. Put the next part in
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your virtual host or any other place.
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ProxyPass /application http://servername:port/somethingelse/
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ProxyPassReverse /application http://servername:port/somethingelse/
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<b>Loadbalance and/or failover</b>
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For this part we need some more modules. So we enable them. You can also enable
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the ftp and ajp connectors if you need them. It's exactly the same as with the
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mod_proxy_http.
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a2enmod proxy proxy_http proxy_balancer
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/etc/init.d/apache2 restart
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Now we can have fun! The ProxyPreserveHost is technically not needed. But there
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are some more options in the proxy module that makes life a little bit easier.
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We will not proxy requests for /context/static. All the rest will be proxied to
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the right server. Server1 is active now. Server2 is disabled. (maintenance?) So
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if Server1 will fail, everybody is moved to a balanced cluster of Server3 and
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Server4. I know, it's a little bit strange setup, but it's only an example.
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ProxyPreserveHost On
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ProxyPass /context/static !
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ProxyPass /context balancer://clustername/something
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<Proxy balancer://clustername>
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BalancerMember http://servername1:port lbset=0 route=server1
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# The next server is temporary disabled.
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BalancerMember http://servername2:port lbset=0 route=server2 status=+D
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#
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# Backupservers if other servers failed
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BalancerMember http://servername3:port lbset=1 route=server3
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BalancerMember http://servername4:port lbset=1 route=server4
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</Proxy>
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