AGamePlayer's questions

This is what I'm looking for:

If the referrer includes https://l.facebook.com/, redirect all the pages to sub.example.com/...

If the referrer includes https://t.co/, redirect all the pages to sub2.example.com/...

How do I do that in my nginx conf?

I am considering move some of my domains to a company with cheaper prices.

Do I have to do anything to my SSL certificates?

Current certs are generated by certbot from Let's Encrypt.

I have never done this before and am quite new to server-side jobs. Thanks for any kind of tips.

I removed a public key in authorized_keys for a computer that I've lost.

I have some servers running on the Debian and am afraid that a reboot would cause some trouble.

However, I can't verify whether the lost-computer can still log in via the key.

Am I all good now or do I still need a reboot?

I'm using Debian 10.

According to the nginx beginner's guide:

Serving Static Content

An important web server task is serving out files (such as images or static HTML pages). You will implement an example where, depending on the request, files will be served from different local directories: /data/www (which may contain HTML files) and /data/images (containing images). This will require editing of the configuration file and setting up of a server block inside the http block with two location blocks.

But most of the nginx conf files are missing this http { ... } part.

I can't find anything on the document describing about it.

Is this http { ... } block just optional? When should I use/omit it?

I saw these lines:

  location = /config.json {
    return 404;
  }

  location = /config.js {
    return 404;
  }

  location /.git {
    return 404;
  }


  location = /50x.html {
    root   html;
  }

I understand the first 3 rules are to forbid users to access the sensitive files but what does the last rule mean? What is root html ?

I am new to nginx, can somebody explain?

nginx -V output:

➜  ~ nginx -V
nginx version: nginx/1.14.0 (Ubuntu)
built with OpenSSL 1.1.1  11 Sep 2018
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fdebug-prefix-map=/build/nginx-H4cN7P/nginx-1.14.0=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_geoip_module=dynamic --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_sub_module --with-http_xslt_module=dynamic --with-stream=dynamic --with-stream_ssl_module --with-mail=dynamic --with-mail_ssl_module

Both are CentOS servers.

Server A:

After running service nginx stop, the Nginx processes are killed.

ps -aux | grep "nginx"
root      1729  0.0  0.0 125600  6488 ?        Ss   Sep15   0:00 nginx: master process /usr/sbin/nginx
root      2240  0.0  0.0 125604  5744 ?        S    Sep15   0:00 nginx: worker process
root      2241  0.0  0.0 125604  5752 ?        S    Sep15   0:00 nginx: worker process
root      2242  0.0  0.0 125604  4100 ?        S    Sep15   0:00 nginx: worker process
root      2243  0.0  0.0 125604  5748 ?        S    Sep15   0:00 nginx: worker process
root      2244  0.0  0.0 125604  4100 ?        S    Sep15   0:00 nginx: worker process
root      2245  0.0  0.0 125604  4304 ?        S    Sep15   0:00 nginx: worker process
root      2246  0.0  0.0 125604  5744 ?        S    Sep15   0:00 nginx: worker process
root      2247  0.0  0.0 125604  5744 ?        S    Sep15   0:00 nginx: worker process
root      2248  0.0  0.0 125604  4044 ?        S    Sep15   0:01 nginx: cache manager process
root      3705  0.0  0.0 112708   988 pts/0    S+   21:15   0:00 grep --color=auto --exclude-dir=.bzr --exclude-dir=CVS --exclude-dir=.git --exclude-dir=.hg --exclude-dir=.svn nginx


➜  ~ service nginx stop    
Redirecting to /bin/systemctl stop nginx.service


➜  ~ ps -aux | grep "nginx"
root      3896  0.0  0.0 112704   988 pts/0    S+   21:16   0:00 grep --color=auto --exclude-dir=.bzr --exclude-dir=CVS --exclude-dir=.git --exclude-dir=.hg --exclude-dir=.svn nginx

server B:

After running service nginx stop, the Nginx processes are NOT killed at all:

[root@machine123 ~]# ps -aux | grep "nginx"
root        1376  0.0  0.1 136592 12592 ?        Ss   09:21   0:00 nginx: master process nginx -c /etc/nginx/nginx.conf
root        1388  0.0  0.1 165788 13072 ?        S    09:21   0:00 nginx: worker process
root        1389  0.0  0.1 165788 11392 ?        S    09:21   0:00 nginx: worker process
root        1390  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1391  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1392  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1393  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1394  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1395  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1396  0.0  0.1 165552  9068 ?        S    09:21   0:00 nginx: cache manager process
root        1892  0.0  0.0  12108  1084 pts/0    S+   09:48   0:00 grep --color=auto nginx


[root@machine123 ~]# service nginx stop
Redirecting to /bin/systemctl stop nginx.service


[root@machine123 ~]# ps -aux | grep "nginx"
root        1376  0.0  0.1 136592 12592 ?        Ss   09:21   0:00 nginx: master process nginx -c /etc/nginx/nginx.conf
root        1388  0.0  0.1 165788 13072 ?        S    09:21   0:00 nginx: worker process
root        1389  0.0  0.1 165788 11392 ?        S    09:21   0:00 nginx: worker process
root        1390  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1391  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1392  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1393  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1394  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1395  0.0  0.1 165788  9260 ?        S    09:21   0:00 nginx: worker process
root        1396  0.0  0.1 165552  9068 ?        S    09:21   0:00 nginx: cache manager process
root        1906  0.0  0.0  12108  1028 pts/0    S+   09:49   0:00 grep --color=auto nginx

Is there anything I can do to debug this?

Thanks for any tips.

systemctl status nginx Results:

[root@machine123 ~]# systemctl status nginx
● nginx.service - The nginx HTTP and reverse proxy server
   Loaded: loaded (/usr/lib/systemd/system/nginx.service; enabled; vendor preset: disabled)
   Active: failed (Result: exit-code) since Fri 2020-09-18 09:34:52 CST; 36min ago
  Process: 1868 ExecStart=/usr/sbin/nginx (code=exited, status=1/FAILURE)
  Process: 1865 ExecStartPre=/usr/sbin/nginx -t (code=exited, status=0/SUCCESS)
  Process: 1862 ExecStartPre=/usr/bin/rm -f /run/nginx.pid (code=exited, status=0/SUCCESS)

Sep 18 09:34:51 machine123 nginx[1868]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Sep 18 09:34:51 machine123 nginx[1868]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Sep 18 09:34:51 machine123 nginx[1868]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Sep 18 09:34:51 machine123 nginx[1868]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Sep 18 09:34:52 machine123 nginx[1868]: nginx: [emerg] bind() to 0.0.0.0:443 failed (98: Address already in use)
Sep 18 09:34:52 machine123 nginx[1868]: nginx: [emerg] bind() to 0.0.0.0:80 failed (98: Address already in use)
Sep 18 09:34:52 machine123 nginx[1868]: nginx: [emerg] still could not bind()
Sep 18 09:34:52 machine123 systemd[1]: nginx.service: Control process exited, code=exited status=1
Sep 18 09:34:52 machine123 systemd[1]: nginx.service: Failed with result 'exit-code'.
Sep 18 09:34:52 machine123 systemd[1]: Failed to start The nginx HTTP and reverse proxy server.

I have encountered a permission error serving my files so I changed the

user www-data;

to

user root;

in the nginx.conf file.

Is there any risk to do so?

There are about 500 concurrent users. It's because some famous people on social network repost a link.

This happened before. And our server were performing good.

But this time, the server is getting very slow and I noticed that the load is very high. In this picture the load is only 83.22 but that's because I rebooted it. Before rebooting it is 600+ (after editing this post, it's climbing to 200+, and it's still climbing, I guess it'd be above 600 soon)

I noticed that there're so many "ss" process. What are them? Any further advice on this case?

Thanks!

Update: after posting this question, it's getting higher:

Update:

I tried to find the source of this "ss" but it's like this:

Update: added another picture for ps auxw

Update:

Used ps aux | grep ss and listed this:

/bin/sh -c ss -nlp | grep "[,=]27846," || netstat -nlp | grep "[[:space:]]27846/"

This might be a very general question but I really like to find some detailed answers or clues.

I am discussing this with a friend, trying to convince him to put more than 300,000 files from one single folder to more than one (like 1000 per sub-directory). Those files are images and to be served online web-viewing, like:

www.example.com/folder/1.png
.
.
.
www.example.com/folder/300000.png

I simply remember many years ago when I worked at a online video serving company like Youtube. We put the screenshots in one folder and then the server were always crashing. At that time a "rumor" saying people should not put many files in one folder, but we do not know the detailed reason.

So how many files should I put in one folder? If there is a limitation, why? Any recommended ways to design this?

My server information:

No LSB modules are available.
Distributor ID: Debian
Description:    Debian GNU/Linux 7.8 (wheezy)
Release:    7.8
Codename:   wheezy

Core Build version:

Linux linode 4.1.5-x86_64-linode61 #7 SMP Mon Aug 24 13:46:31 EDT 2015 x86_64 GNU/Linux

I guess this case applies to many different kind of server software.

I set up a VPN with pptpd on my Linux server. For many months it works fine. But suddenly it failed.

The VPN can be successfully connected but no traffic can come in.

Is there anything I can try to debug this?

I am trying to setup a SVN on my linode server (Debian).

https://library.linode.com/linux-tools/version-control/svn I found an article here but it only tells me how to setup with Apache. I am using Nginx instead, how do I set up?

I hope to set up my own SVN server and check out the files via http:// protocol, rather than svn+ssh://

Thanks,

I've been using SSH tunnel for a while on Windows (using Putty).

On Windows with putty, it is always fine, but on mac or cygwin, it sometimes prompts the warning message:

open failed: administratively prohibited: open failed