nginx sometimes gets killed after reloading it using systemd

Question

After upgrading my Ubuntu server to 20.04 from 18.04 the nginx started with strange behaviour. It dies randomly on systemctl reload nginx and complains that there is already process listening on given ports. Before I'm able to run portmap or something similar I'm already able to start nginx using systemctl start nginx with no problems so I think the problem is nginx is trying to bind to ports which are already taken by the old nginx being reloaded.

I haven't tried much because I'm lost. I've checked that the /run/nginx.pid contains correct pid. There is docker on my server so I thought maybe some container starts trying to bind 80 or 443 but no. The only mapped port for docker is 8090.

Versions:

nginx -v
nginx version: nginx/1.18.0 (Ubuntu)

cat /etc/os-release 
VERSION="20.04.1 LTS (Focal Fossa)"
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
...

Configuration files are valid:

nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

All ports nginx binds to are the same it complains about in the journal log:

cat /etc/nginx/sites-enabled/* | grep listen | uniq
listen 80 default_server;
listen 127.0.0.1:8080;
listen 443 ssl http2;
listen [::]:443 ssl http2;

Do you have any idea why nginx would die on reload? What more can I check?

Logs produced

dmesg

[31326.529427] traps: nginx[746] general protection fault ip:7f5f8cadc593 sp:7ffd350738d0 error:0 in libperl.so.5.30.0[7f5f8ca74000+166000]
[31408.549262] traps: nginx[26366] general protection fault ip:7efda22e8593 sp:7ffda51c0bd0 error:0 in libperl.so.5.30.0[7efda2280000+166000]
[32103.236557] nginx[26433]: segfault at 3d1 ip 00007efe600ce5c9 sp 00007ffead1b3210 error 4 in libperl.so.5.30.0[7efe60066000+166000]
[32103.236566] Code: 00 0f b6 40 30 49 c1 ed 03 49 29 c5 0f 84 17 01 00 00 48 8b 76 10 48 8b 52 10 4c 8d 3c fe 4c 8d 0c c2 84 c9 0f 84 c7 02 00 00 <49> 83 39 00 0f 85 ad 03 00 00 49 83 c1 08 49 83 ed 01 49 8d 74 1d
[32676.779937] nginx[31927]: segfault at 10 ip 00007f7550de2593 sp 00007ffce0bf4cd0 error 4 in libperl.so.5.30.0[7f7550d7a000+166000]
[32676.779952] Code: 48 89 43 10 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 1f 40 00 0f b6 7f 30 48 c1 e8 03 48 29 f8 48 89 c3 74 89 48 8b 02 <4c> 8b 68 10 4d 85 ed 0f 84 28 01 00 00 0f b6 40 30 49 c1 ed 03 49
[33337.193774] traps: nginx[32415] general protection fault ip:7f195aa5e593 sp:7ffca566bad0 error:0 in libperl.so.5.30.0[7f195a9f6000+166000]
[40155.333210] nginx[39879]: segfault at 41 ip 00007fe42f53c593 sp 00007ffe812e18f0 error 4 in libperl.so.5.30.0[7fe42f4d4000+166000]
[40155.333219] Code: 48 89 43 10 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e 41 5f c3 0f 1f 40 00 0f b6 7f 30 48 c1 e8 03 48 29 f8 48 89 c3 74 89 48 8b 02 <4c> 8b 68 10 4d 85 ed 0f 84 28 01 00 00 0f b6 40 30 49 c1 ed 03 49

Journal

Oct 28 01:32:24 fooServer systemd[1]: Starting A high performance web server and a reverse proxy server...
Oct 28 01:32:25 fooServer systemd[1]: Started A high performance web server and a reverse proxy server.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Main process exited, code=killed, status=11/SEGV
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 587 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2048 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2049 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2050 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2051 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2052 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2053 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2054 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2055 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 587 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2048 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2049 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2050 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2051 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2052 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2053 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2054 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Killing process 2055 (nginx) with signal SIGKILL.
Oct 28 01:35:05 fooServer systemd[1]: nginx.service: Failed with result 'signal'.
Nov 02 05:32:05 fooServer systemd[1]: Starting A high performance web server and a reverse proxy server...
Nov 02 05:32:05 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:05 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:05 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:05 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:05 fooServer nginx[415078]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:06 fooServer nginx[415078]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:07 fooServer nginx[415078]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:08 fooServer nginx[415078]: nginx: [emerg] still could not bind()
Nov 02 05:32:08 fooServer systemd[1]: nginx.service: Control process exited, code=exited, status=1/FAILURE
Nov 02 05:32:08 fooServer systemd[1]: nginx.service: Failed with result 'exit-code'.
Nov 02 05:32:08 fooServer systemd[1]: Failed to start A high performance web server and a reverse proxy server.
Nov 02 05:32:17 fooServer systemd[1]: Starting A high performance web server and a reverse proxy server...
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:17 fooServer nginx[415100]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:18 fooServer nginx[415100]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:19 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Nov 02 05:32:19 fooServer nginx[415100]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Nov 02 05:32:19 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
Nov 02 05:32:19 fooServer nginx[415100]: nginx: [emerg] bind() to [::]:443 failed (98: Address already in use)
Nov 02 05:32:19 fooServer nginx[415100]: nginx: [emerg] bind() to 127.0.0.1:8080 failed (98: Address already in use)
Nov 02 05:32:19 fooServer nginx[415100]: nginx: [emerg] still could not bind()
Nov 02 05:32:19 fooServer systemd[1]: nginx.service: Control process exited, code=exited, status=1/FAILURE
Nov 02 05:32:19 fooServer systemd[1]: nginx.service: Failed with result 'exit-code'.
Nov 02 05:32:19 fooServer systemd[1]: Failed to start A high performance web server and a reverse proxy server.

/var/log/nginx/error.log:

2020/11/02 21:49:38 [info] 25842#25842: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 21:49:40 [notice] 25846#25846: signal process started
2020/11/02 21:51:09 [notice] 26353#26353: signal process started
2020/11/02 21:51:19 [info] 26357#26357: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 21:51:28 [info] 26364#26364: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 21:52:31 [notice] 26406#26406: signal process started
2020/11/02 21:52:31 [notice] 26418#26418: signal process started
2020/11/02 21:52:38 [info] 26431#26431: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 21:58:54 [info] 26584#26584: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 21:58:57 [notice] 26589#26589: signal process started
2020/11/02 22:04:04 [info] 31847#31847: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 22:04:06 [notice] 31855#31855: signal process started
2020/11/02 22:06:05 [info] 31925#31925: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 22:12:39 [notice] 32321#32321: signal process started
2020/11/02 22:13:40 [notice] 32392#32392: signal process started
2020/11/02 22:13:53 [info] 32413#32413: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74
2020/11/02 22:24:13 [notice] 39657#39657: signal process started
2020/11/02 22:24:40 [notice] 39837#39837: signal process started
2020/11/02 22:24:45 [info] 39870#39870: Using 32768KiB of shared memory for nchan in /etc/nginx/nginx.conf:74

Configuration

/etc/nginx/nginx.conf:

user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
    worker_connections 768;
    # multi_accept on;
}

http {
    ##
    # Basic Settings
    ##

    sendfile on;
    tcp_nopush on;
    tcp_nodelay on;
    keepalive_timeout 65;
    types_hash_max_size 2048;
    server_tokens off;
    client_max_body_size 1G;

    # server_names_hash_bucket_size 64;
    # server_name_in_redirect off;

    include /etc/nginx/mime.types;
    default_type application/octet-stream;

    ##
    # SSL Settings
    ##

    ssl_session_timeout 1d;
    ssl_session_cache shared:MozSSL:10m;  # about 40000 sessions
    ssl_session_tickets off;

    # curl https://ssl-config.mozilla.org/ffdhe2048.txt > /path/to/dhparam.pem
    ssl_dhparam /etc/nginx/ssl/dhparam.pem;

    # intermediate configuration
    ssl_protocols TLSv1.2 TLSv1.3;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers off;

    # HSTS (ngx_http_headers_module is required) (63072000 seconds)
    add_header Strict-Transport-Security "max-age=63072000" always;

    ##
    # Logging Settings
    ##

    access_log /var/log/nginx/access.log;
    error_log /var/log/nginx/error.log;

    ##
    # Gzip Settings
    ##

    gzip on;
    gzip_vary on;
    gzip_proxied any;
    gzip_comp_level 6;
    gzip_buffers 16 8k;
    gzip_http_version 1.1;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

    ##
    # Virtual Host Configs
    ##

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;
}

most of my /etc/nginx/sites-enabled/*.conf looks like this one:

  listen 443 ssl http2;
  server_name example.com;

  root /var/www/public;

  include fpm7.3.conf; # includes fastcgi_pass to php-fpm for *.php files

  ssl_certificate /etc/letsencrypt/live/example.com/fullchain.pem;
  ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;
  ssl_trusted_certificate /etc/letsencrypt/live/example.com/fullchain.pem;

  error_log /var/log/nginx/example.com.error.log;
  access_log /var/log/nginx/example.com.access.log;
}

Answer 1

You've run into a bug in perl 5.30, the version used in Ubuntu 20.04 LTS. The bug has been fixed upstream but that fix has not yet been backported to Ubuntu.

If you haven't got a need to run Perl code inside nginx (as most people do not) then you can uninstall the package libnginx-mod-http-perl and restart nginx to avoid the problem. This package was pulled in by the virtual package nginx-extras but most people don't actually run perl in the web server and so don't need it.

ubuntu@vmtest-ubuntu2004:~$ sudo apt purge libnginx-mod-http-perl
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libhiredis0.14 libluajit-5.1-2 libluajit-5.1-common
  libnginxroot@vmtest-ubuntu2004:~# apt purge libnginx-mod-http-perl
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  libhiredis0.14 libluajit-5.1-2 libluajit-5.1-common
  libnginx-mod-http-auth-pam libnginx-mod-http-cache-purge
  libnginx-mod-http-dav-ext libnginx-mod-http-echo
  libnginx-mod-http-fancyindex libnginx-mod-http-geoip
  libnginx-mod-http-geoip2 libnginx-mod-http-headers-more-filter
  libnginx-mod-http-lua libnginx-mod-http-ndk libnginx-mod-http-subs-filter
  libnginx-mod-http-uploadprogress libnginx-mod-http-upstream-fair
  libnginx-mod-nchan
Use 'apt autoremove' to remove them.
The following additional packages will be installed:
  nginx-core
Suggested packages:
  nginx-doc
The following packages will be REMOVED:
  libnginx-mod-http-perl* nginx-extras*
The following NEW packages will be installed:
  nginx-core
0 upgraded, 1 newly installed, 2 to remove and 0 not upgraded.
Need to get 425 kB of archives.
After this operation, 173 kB disk space will be freed.
Do you want to continue? [Y/n]

---

ubuntu@vmtest-ubuntu2004:~$ sudo systemctl restart nginx

Though in this specific case, nginx has probably gone zombie and you will have to restart the computer.

As shown above, removing it will replace nginx-extras with nginx-core, and mark all the extras packages as eligible for autoremoval, so if you actually need any of those packages you should mark them as installed before autoremoving.

ubuntu@vmtest-ubuntu2004:~$ sudo apt-mark install libnginx-mod-http-geoip2
Selected libnginx-mod-http-geoip2 for installation.

You can also follow the issue on Launchpad.