"No protocol handler valid for the URL" with httpd mod_proxy_balancer

Solution 1:

facepalm

It turns out that I was missing a trailing slash on my ProxyPass directive:

ProxyPass "/site/" "balancer://cms"

should have been:

ProxyPass "/site/" "balancer://cms/"

(Note the trailing slash before the close-quote.)

That literally fixed everything.

I'm happy to delete this question and answer if folks want to close it as "simple typographical error", but I'll leave it for now. If I get some up votes on this answer, I'll remove this note and consider it a public service for anyone who might make the same mistake.

Solution 2:

In my case, I needed proxy_ajp module.

a2enmod proxy proxy_http proxy_ajp 

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Solution 3:

Same as kujiy i had to add the mod_ajp.

I am using apache4.

My log showed messages as follows:

No protocol handler was valid for the URL /jira. 
If you are using a DSO version of mod_proxy, 
make sure the proxy submodules are included in 
the configuration using LoadModule 

so I added ( I mean uncommented) the following line to my httpd.conf:

LoadModule proxy_ajp_module modules/mod_proxy_ajp.so 

saved, and the restarted the apache server.