(First post in the Nginx forum, so please bear with me if it seems
I’m the maker of Engintron, a popular cPanel plugin which integrates
as a reverse caching proxy in front of Apache. The project started in
2014, it is open source & free and you can check out the code here,
including Nginx configuration files:
In Feb 2016 I rewrote the plugin from scratch using a more efficient
universal proxy configuration in Nginx, for any domain hosted on a
server. The benefit is that you install Engintron on your cPanel server
it just works, with zero maintenance and no vhost sync’ing between Nginx
Apache like similar plugins for cPanel.
I am defining 2 proxy cache zones/pools plus a proxy temp location in
/etc/nginx/nginx.conf like this:
proxy_cache_path /tmp/engintron_dynamic levels=1:2
keys_zone=engintron_dynamic:20m inactive=10m max_size=500m;
proxy_cache_path /tmp/engintron_static levels=1:2
keys_zone=engintron_static:20m inactive=10m max_size=500m;
Nginx does 1 min caching for static assets like CSS, JS, images etc. and
sec micro-caching for dynamic/HTML content. The latter is used so that
doesn’t break sites with user-generated content such as forums,
In CentOS versions 5 & 6, the folders referenced above will start
when Nginx is installed via Engintron, as Nginx caching kicks in.
In CentOS 7 however - and this has been verified in multiple cPanel
installations on my end, as well as other Engintron users via the
Issues section on GitHub- the above folders are just empty.
However caching DOES work in CentOS 7, at least according to the headers
sent by Nginx as well as by checking a static file if it gets cached.
For example if I modify this CSS file
see any changes until a minute has passed (1 min static cache). So the
does indeed get cached by Nginx, but the cache entry does not appear in
proxy cache/temp folders. These folders show up as empty with a simple
And if you check the same file via curl, you get something like this:
$ curl -I
HTTP/1.1 200 OK
Date: Wed, 06 Apr 2016 04:27:52 GMT
Last-Modified: Wed, 06 Apr 2016 04:25:52 GMT
Expires: Fri, 06 May 2016 04:27:52 GMT
I’m really out of ideas why on earth there’s this behaviour with CentOS
Any pointers would be appreciated.
For the record, the (re-written) release of Engintron in Feb 2016
has more than 1300 server deployments in 72 countries worldwide.
It’s in my plans to also get anonymous system metrics at some point in
near future, so I know which CentOS version is used (along with other
such Apache version, MySQL version etc.). In the meantime I can’t know
percentage uses CentOS 7, but judging from the fact that new cPanel
deployments usually get setup on CentOS 7, I’m assuming the percentage
be high overall.
Thanks in advance for any help or guidance.
Posted at Nginx Forum: