Turns out I didn’t properly read the error log (They have suffixes such as 06-28 and I just tried to read the most recent one which contained nothing). The error is “Permission Denied” when Nginx was trying to connect to the Cowboy server, which was already asked here: https://stackoverflow.com/questions/23948527/13-permission-denied-while-connecting-to-upstreamnginx. The solution is to change httpd setting in SELinux: setsebool -P httpd_can_network_connect 1. HAProxy isn’t restricted by this setting on httpd, apparently.
SZJX
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OvermindDL1
That sounds unsafe…
But yeah, if you have selinux enabled then it is pretty obvious that you need to allow the connection… ^.^;
A quick set of commands that would generally work in this case would be something like:
# See what it will enable:
sudo cat /var/log/audit/audit.log | grep nginx | grep denied | audit2allow -m nginxlocalconf > nginxlocalconf.te
view nginxlocalconf.te
# If the above is good then commit the changes:
sudo cat /var/log/audit/audit.log | grep nginx | grep denied | audit2allow -M nginxlocalconf
sudo semodule -i nginxlocalconf.pp
# See what is allowed to httpd by:
sudo semanage port -l | grep http
# You can add a specific port, like say 6080, by something like:
sudo semanage port -a -t http_port_t -p tcp 6080
In essence, if one does not know selinux decently, don’t use it unless required (though it is worth learning, it is very powerful).
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