nginx – setup as reverse proxy

Previously to take down this wordpress site all you needed to do was hold down F5 for about 20 seconds then the site would take about 5 mins to recover.

There were a few factors causing this and quite a few different methods to solving the problem. WordPress itself is run on php / apache, apache has an evasive mod which can block certain IPs depending on the defined abusive behavior (typical DDOS attack). Since i like to run a few websites behind a single IP i looked at fixing the issue closer to the perimeter….

Enter nginx (engine x) as a reverse proxy, the site now typically caches all content and serves it straight out of memory. No longer does mysql / apache kill itself under high load on the backend…

nginx

You will need to create the nginx directories if they dont already exist. Check /var/log/nginx/error.log (default ubuntu) if any issues starting the service.

sudo aptitude install nginx
sudo service nginx start

The following added to http {}
(located in /etc/nginx/nginx.conf)

log_format cache '***$time_local '
'$remote_addr '
'$upstream_cache_status '
'Cache-Control: $upstream_http_cache_control '
'Expires: $upstream_http_expires '
'"$request" ($status) ';
access_log /var/log/nginx/access.log cache;
error_log /var/log/nginx/error.log;
server_names_hash_bucket_size 64;
proxy_cache_path /var/www/nginx_cache levels=1:2
keys_zone=one:10m
max_size=1g inactive=30m;
proxy_temp_path /var/www/nginx_temp;

the following added to location / {}
(located in /etc/nginx/sites-enabled/default)

proxy_pass http://sigtar;
proxy_next_upstream error timeout invalid_header http_500 http_502 http_503 http_504;
proxy_redirect off;
proxy_buffering on;
proxy_buffer_size 16k;
proxy_buffers 32 16k;
proxy_cache one;
proxy_cache_valid 200 302 304 10m;
proxy_cache_valid 301 1h;
proxy_cache_valid any 1m;
client_body_buffer_size 128k;
proxy_busy_buffers_size 64k;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_pass_header Set-Cookie;

Note if you have problems with wordpress redirect issues… check this post;

http://tommcfarlin.com/resolving-the-wordpress-multisite-redirect-loop/

Also confirm you have this line in http {}

server_names_hash_bucket_size 64;

Very basic load test, user load time is reasonably consistent as user count increases.
http://loadimpact.com/load-test/sigtar.com-ad07b7870a75c854a935752b0a032c53

load test

use nmap to port scan / find free IPS

I use angry IP scanner in windows, linux has a good util for port scanning an ip range called nmap;

Grab nmap from usual repositories

sudo nmap -sP 192.168.9.0/24 (will show hosts up and resolve mac addresses to vendors)

sudo nmap -v -sT 192.168.9.0/24 (will show hosts up and the various open ports)

sudo nmap -v -sT 192.168.9.104 (will show particular host and the various open ports)

Starting Nmap 6.00 ( http://nmap.org ) at 2013-07-12 11:48 NZST
Initiating ARP Ping Scan at 11:48
Scanning 192.168.9.104 [1 port]
Completed ARP Ping Scan at 11:48, 0.00s elapsed (1 total hosts)
Initiating Parallel DNS resolution of 1 host. at 11:48
Completed Parallel DNS resolution of 1 host. at 11:48, 0.00s elapsed
Initiating Connect Scan at 11:48
Scanning win2012-veeam.fritz.box (192.168.9.104) [1000 ports]
Discovered open port 111/tcp on 192.168.9.104
Discovered open port 445/tcp on 192.168.9.104
Discovered open port 3389/tcp on 192.168.9.104
Discovered open port 135/tcp on 192.168.9.104
Discovered open port 139/tcp on 192.168.9.104
Discovered open port 49155/tcp on 192.168.9.104
Discovered open port 1063/tcp on 192.168.9.104
Discovered open port 2049/tcp on 192.168.9.104
Discovered open port 3260/tcp on 192.168.9.104
Completed Connect Scan at 11:48, 4.21s elapsed (1000 total ports)
Nmap scan report for win2012-veeam.fritz.box (192.168.9.104)
Host is up (0.00059s latency).
Not shown: 991 filtered ports
PORT STATE SERVICE
111/tcp open rpcbind
135/tcp open msrpc
139/tcp open netbios-ssn
445/tcp open microsoft-ds
1063/tcp open kyoceranetdev
2049/tcp open nfs
3260/tcp open iscsi
3389/tcp open ms-wbt-server
49155/tcp open unknown
MAC Address: 00:50:56:9C:68:FA (VMware)

Read data files from: /usr/bin/../share/nmap
Nmap done: 1 IP address (1 host up) scanned in 4.25 seconds
Raw packets sent: 1 (28B) | Rcvd: 1 (28B)

squid – reverse proxy

Great guide here – http://www.classhelper.org/articles/reverse-proxy-server-squid-debian/installing-squid-proxy-server.shtml

I’ve modified slightly for Ubuntu, but almost identical.

apt-get install squid
cp /etc/squid3/squid.conf /etc/squid3/squid.bak
rm /etc/squid3/squid.conf
nano /etc/squid/squid.conf

http_port 80 defaultsite=www.yoursite.com vhost
forwarded_for on
refresh_pattern ^ftp: 1440 20% 10080
refresh_pattern ^gopher: 1440 0% 1440
refresh_pattern . 0 20% 4320
cache_peer 192.168.0.13 parent 80 0 no-query no-digest originserver name=web1
acl sites_web1 dstdomain www.yoursite.com yoursite.com
cache_peer_access web1 allow sites_web1
cache_peer 192.168.0.14 parent 80 0 no-query no-digest originserver name=web2
acl sites_web2 dstdomain www.anothersite.com anothersite.com
cache_peer_access web2 allow sites_web2
acl all src 0.0.0.0/0.0.0.0
acl manager proto cache_object
acl localhost src 127.0.0.1/255.255.255.255
acl to_localhost dst 127.0.0.0/8
acl SSL_ports port 443
acl Safe_ports port 80 # http
acl Safe_ports port 443 # https
acl Safe_ports port 1025-65535 # unregistered ports
acl CONNECT method CONNECT
http_access allow sites_web1
http_access allow sites_web2
http_access allow manager all
http_access allow manager
http_access deny !Safe_ports
http_access deny CONNECT !SSL_ports
#http_access deny all
access_log /var/log/squid3/access.log
cache_mgr support@yoursite.com

 

Modify your hosts file to include web1 and web2

nano /etc/hosts

192.168.0.13 web1
192.168.0.14 web2

Another good article about benefits of reverse proxy

http://2bits.com/articles/increasing-drupals-speed-squid-caching-reverse-proxy.html