Hi All,

I am getting: tons of AH01114: HTTP: failed to make a connection to backend: localhost in /var/log/http/error.log

what happening?

==
<VirtualHost *:80>
ServerName xxx.xxxxx.xxx
ServerAlias xxx.xxxxx.xxx

ServerAdmin xxx@xxx.xxxx
DocumentRoot /var/www/html/xxxx

<Directory /var/www/html/xxxx
Options -Indexes +FollowSymLinks
AllowOverride All
</Directory>^M

ErrorLog ${APACHE_LOG_DIR}/xxx.xxxx.xxx-error.log
CustomLog ${APACHE_LOG_DIR}/xxxx.xxx.xxx.access.log combined
RewriteEngine on
RewriteCond %{SERVER_NAME} =xxx.xxx.xxx
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
Redirect permanent / https://xxx.xxx.xxx
</VirtualHost>


<IfModule mod_ssl.c>
<VirtualHost *:443>
ServerName xxxx.xxx.xxx
ServerAlias xxxx.xxx.xxx
ServerAdmin xxx@xxxx.xxx
DocumentRoot /var/www/html/xxxx

<Directory /var/www/html/xxxx
Options -Indexes +FollowSymLinks
AllowOverride All
</Directory>

SSLEngine On
SSLProxyEngine On
ProxyRequests Off
ProxyPreserveHost On

ProxyPass / http://localhost:5000/
ProxyPassReverse / http://localhost:5000/

..
....
....
</VirtualHost>
</IfModule>
~
~

~

==

You have setup the vhost xxx.xxxxx.xxx as a reverse proxy for an application running on the same host and listening on port 5000.

So make sure that this application (whatever it is), is indeed running and listening on port 5000 on the local loopback interface

yes, the app is running and listening on port 5000, but don't know why I got that error

Are you sure it's listening on the local loopback interface?
What gives:

Yes, it is listening (see the screenshot)

Attached Thumbnails

 

Then maybe your box does not resolve localhost to 127.0.0.1.
Check /etc/hosts and/or change the apache proxypass directives to:

Hi,

the problem still occurs:

[Mon Jun 14 11:55:01.253497 2021] [proxy:error] [pid 392251:tid 140209995896576] (99)Cannot assign requested address: AH00957: HTTP: attempt to connect to 127.0.0.1:5000 (127.0.0.1) failed
[Mon Jun 14 11:55:01.253522 2021] [proxy_http:error] [pid 392251:tid 140209995896576] [client 36.67.59.59:35738] AH01114: HTTP: failed to make connection to backend: 127.0.0.1

what happens with my apache?

<IfModule mod_ssl.c>
<VirtualHost *:443>
ServerName gps.example.com
ServerAlias gps.example.com
DocumentRoot /var/www/html
ErrorLog /var/log/httpd/error.log
CustomLog /var/log/httpd/requests.log combined

ProxyRequests Off
ProxyPreserveHost On
RewriteEngine On

ProxyPass /gps/v1/api/ http://127.0.0.1:5000/
ProxyPassReverse /gps/v1/api/ http://127.0.0.1:5000/

SSLCertificateFile /etc/letsencrypt/live/gps.example.com/fullchain.pem
SSLCertificateKeyFile /etc/letsencrypt/live/gps.example.com/privkey.pem
Include /etc/letsencrypt/options-ssl-apache.conf
</VirtualHost>
</IfModule>
~

I don't understand the error above? Do you get that error when visiting https://gps.example.com/gps/v1/api/
What happens if you go directly to http://127.0.0.1:5000/ from the same box that runs the apache reverse proxy?