Installing LibreNMS on Ubuntu 20.04 with NGINX, getting "502 Bad Gateway" in the Web Installer step

[CatchyNick]

Hi,

I’m trying to install LibreNMS on a freshly installed Ubuntu 20.04 server, with all the updates.
After following the installation instructions carefully (https://docs.librenms.org/Installation/Install-LibreNMS/), with the Ubuntu 20.04 and NGINX options, I’m getting “502 Bad Gateway” error in the ‘Web installer’ section.

There is nothing in the ‘/etc/nginx/sites-enabled/’ directory, and in the ‘/etc/nginx/sites-available’ directory the only file is ‘default’.

Seems like some steps are missing from the ‘Configure Web Server’ section in the installation guide.

Any help how to fix?

Thanks

[Killo_RIchards]

Good morning. Someone had a similar issue not long ago…It looks like you may have missed a few steps:
In /etc/php/7.4/fpm/pool.d - do you have a librenms.conf file? If not, do the following.

cp /etc/php/7.4/fpm/pool.d/www.conf /etc/php/7.4/fpm/pool.d/librenms.conf
vi /etc/php/7.4/fpm/pool.d/librenms.conf

CentOS 8 Debian 10

# Change "www" to "librenms"
[librenms]

# Change user and group to "librenms"
user = librenms
group = librenms

# Change listen to a unique name
listen = /run/php-fpm-librenms.sock

next, do the configuration for the web server:

vi /etc/nginx/conf.d/librenms.conf
```server {
 listen      80;
 server_name librenms.example.com;
 root        /opt/librenms/html;
 index       index.php;

 charset utf-8;
 gzip on;
 gzip_types text/css application/javascript text/javascript application/x-javascript image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon;
 location / {
  try_files $uri $uri/ /index.php?$query_string;
 }
 location ~ [^/]\.php(/|$) {
  fastcgi_pass unix:/run/php-fpm-librenms.sock;
  fastcgi_split_path_info ^(.+\.php)(/.+)$;
  include fastcgi.conf;
 }
 location ~ /\.(?!well-known).* {
  deny all;
 }
}

rm /etc/nginx/sites-enabled/default
systemctl restart nginx
systemctl restart php7.4-fpm

[CatchyNick]

Hi, thanks for answering.

I did all that:

root@aragorn:~# cat /etc/php/7.4/fpm/pool.d/librenms.conf
; Start a new pool named ‘www’.
; the variable $pool can be used in any directive and will be replaced by the
; pool name (‘www’ here)
[librenms]
; Per pool prefix
; It only applies on the following directives:
; - ‘access.log’
; - ‘slowlog’
; - ‘listen’ (unixsocket)
; - ‘chroot’
; - ‘chdir’
; - ‘php_values’
; - ‘php_admin_values’
; When not set, the global prefix (or /usr) applies instead.
; Note: This directive can also be relative to the global prefix.
; Default Value: none
;prefix = /path/to/pools/$pool
; Unix user/group of processes
; Note: The user is mandatory. If the group is not set, the default user’s group
; will be used.
user = librenms
group = librenms
; The address on which to accept FastCGI requests.
; Valid syntaxes are:
; ‘ip.add.re.ss:port’ - to listen on a TCP socket to a specific IPv4 address on
; a specific port;
; ‘[ip:6:addr:ess]:port’ - to listen on a TCP socket to a specific IPv6 address on
; a specific port;
; ‘port’ - to listen on a TCP socket to all addresses
; (IPv6 and IPv4-mapped) on a specific port;
; ‘/path/to/unix/socket’ - to listen on a unix socket.
; Note: This value is mandatory.
listen = /run/php/php-fpm-librenms.sock

and:

root@aragorn:~# cat /etc/nginx/conf.d/librenms.conf
server {
listen 80;
server_name aragorn.local.lan;
root /opt/librenms/html;
index index.php;

charset utf-8;
gzip on;
gzip_types text/css application/javascript text/javascript application/x-javascript image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon;
location / {
try_files $uri $uri/ /index.php?$query_string;
}
location ~ [^/].php(/|$) {
fastcgi_pass unix:/run/php-fpm-librenms.sock;
fastcgi_split_path_info ^(.+.php)(/.+)$;
include fastcgi.conf;
}
location ~ /.(?!well-known).* {
deny all;
}
}

But I’m still getting:

502 Bad Gateway
nginx/1.18.0 (Ubuntu)

[Killo_RIchards]

Interesting…the ubuntu / debian instructions are different…even though ubuntu is based on Debian.
Odd stuff. I genuinely don’t know enough about that to comment on it.

Perhaps try:

vi /etc/nginx/sites-enabled/librenms.vhost

Add the following config, edit server_name as required:

server {
 listen      80;
 server_name librenms.example.com;
 root        /opt/librenms/html;
 index       index.php;

 charset utf-8;
 gzip on;
 gzip_types text/css application/javascript text/javascript application/x-javascript image/svg+xml text/plain text/xsd text/xsl text/xml image/x-icon;
 location / {
  try_files $uri $uri/ /index.php?$query_string;
 }
 location ~ [^/]\.php(/|$) {
  fastcgi_pass unix:/run/php-fpm-librenms.sock;
  fastcgi_split_path_info ^(.+\.php)(/.+)$;
  include fastcgi.conf;
 }
 location ~ /\.(?!well-known).* {
  deny all;
 }
}

rm /etc/nginx/sites-enabled/default
systemctl reload nginx
systemctl restart php7.3-fpm

[CatchyNick]

With the vhost file now in sites-enabled directory, I’m still getting:

502 Bad Gateway
nginx/1.18.0 (Ubuntu)

Also tried to restart the server, but no help

[Killo_RIchards]

here’s a similar recent thread - maybe there’s something in here that’s worth looking at:

Stuck installing on Debian 10: 502 Bad Gateway error when trying to get to install.php

My permissions seem to be reading root@nooty:/var/run/php# ls -l total 4 -rw-r--r-- 1 root root 5 Aug 28 16:18 php7.3-fpm.pid srw-rw---- 1 librenms librenms 0 Aug 28 16:18 php7.3-fpm.sock these are created when the php7.4-fpm service is running. so … i got back into /etc/php/7.3/fpm/pool.d/librenms.conf and turned listen-owner and listen-data back to www-data… and i seem to be getting somewhere now (connecting by IP /install.php, it shows more steps - bacck in a bit …

[Killo_RIchards]

also, might be worth creating a phpinfo.php file and drop that in your web directory and see if your server will serve it up. can also do the same with just a “test.htm” file just testing and see if you can browse to that. That would tell us if the web server is serving correctly, whether there’s a problem with PHP or not and whether there’s a problem with librenms.

[mcand0]

Hi, I had the same problem and solved with this change in /etc/php/7.4/fpm/pool.d/librenms.conf file:

user = librenms
group = librenms
listen = /run/php/php-fpm-librenms.sock
;listen = /run/php/php7.4-fpm.sock

; Set listen(2) backlog.
; Default Value: 511 (-1 on FreeBSD and OpenBSD)
;listen.backlog = 511

; Set permissions for unix socket, if one is used. In Linux, read/write
; permissions must be set in order to allow connections from a web server. Many
; BSD-derived systems allow connections regardless of permissions.
; Default Values: user and group are set as the running user
; mode is set to 0660

listen.owner = www-data
listen.group = www-data
;listen.mode = 0660

Also in /etc/nginx/conf.d/librenms.conf change line 14 into this:

fastcgi_pass unix:/run/php/php-fpm-librenms.sock;

Restart both services and it should work.

[aistech]

Having similar issues, and have not found a resolution, any help would be greatly appreciated,.

502 Bad Gateway

nginx/1.17.10 (Ubuntu 18.04)

validate.php output -
$ ./validate.php

Component	Version
LibreNMS	1.70.1-1-ga3635d0b7
DB Schema	2020_10_12_095504_mempools_add_oids (191)
PHP	7.4.13
Python	3.6.9
MySQL	10.1.47-MariaDB-0ubuntu0.18.04.1
RRDTool	1.7.0
SNMP	NET-SNMP 5.7.3

====================================

[OK] Composer Version: 2.0.8
[OK] Dependencies up-to-date.
[OK] Database connection successful
[OK] Database schema correct

daily.sh output -
$ ./daily.sh
Updating to latest codebase OK
Updating Composer packages OK
Updating SQL-Schema OK
Updating submodules OK
Cleaning up DB OK
Fetching notifications OK
Caching PeeringDB data

[aistech]

PROBLEM SOLVED, as it turns out, I had a typo in my php-fpm.d/www.conf

Listen = /run/php/php-fpm-librenms.sock

Thanks.

[Syed_Jahanzaib]

@mcand0

/etc/nginx/conf.d/librenms.conf

this sorted my issue as well. thx for sharing