Clever Geek Handbook

Installing the HAProxy load balancer on CentOS

The translation of the article was prepared on the eve of the start of the course “Linux Administrator. Virtualization and Clustering "







— - . HAProxy , .



HAProxy , , . Linux, CentOS 8, , Debian 8 Ubuntu 16.





HAProxy - - . HAProxy CentOS 8, -.



- . - -, nginx httpd, .



HAProxy CentOS 8



, HAProxy — , , CentOS, . , :



sudo yum info haproxy


HAProxy : , , . , HAProxy, , .



2.0, . . , .



sudo yum install gcc pcre-devel tar make -y


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wget http://www.haproxy.org/download/2.0/src/haproxy-2.0.7.tar.gz -O ~/haproxy.tar.gz


:



tar xzvf ~/haproxy.tar.gz -C ~/


:



cd ~/haproxy-2.0.7


:



make TARGET=linux-glibc


, , HAProxy:



sudo make install


HAProxy , . .



HAProxy



HAProxy:



sudo mkdir -p /etc/haproxy
sudo mkdir -p /var/lib/haproxy 
sudo touch /var/lib/haproxy/stats


, HAProxy :



sudo ln -s /usr/local/sbin/haproxy /usr/sbin/haproxy


- , haproxy.init examples /etc/init.d. , , systemd:



sudo cp ~/haproxy-2.0.7/examples/haproxy.init /etc/init.d/haproxy
sudo chmod 755 /etc/init.d/haproxy
sudo systemctl daemon-reload


:



sudo chkconfig haproxy on


HAProxy:



sudo useradd -r haproxy


:



haproxy -v
HA-Proxy version 2.0.7 2019/09/27 - https://haproxy.org/


2.0.7, .



, CentOS 8 . , :



sudo firewall-cmd --permanent --zone=public --add-service=http
sudo firewall-cmd --permanent --zone=public --add-port=8181/tcp
sudo firewall-cmd --reload




HAProxy — . , , , HAProxy, .



/etc/haproxy/haproxy.cfg . HAProxy , .



(layer 4)



. , , vi :



sudo vi /etc/haproxy/haproxy.cfg


. server_name , , private_ip — IP- , -. IP- UpCloud Private network Network.



global
   log /dev/log local0
   log /dev/log local1 notice
   chroot /var/lib/haproxy
   stats timeout 30s
   user haproxy
   group haproxy
   daemon

defaults
   log global
   mode http
   option httplog
   option dontlognull
   timeout connect 5000
   timeout client 50000
   timeout server 50000

frontend http_front
   bind *:80
   stats uri /haproxy?stats
   default_backend http_back

backend http_back
   balance roundrobin
   server server_name1 private_ip1:80 check
   server server_name2 private_ip2:80 check


(layer 4) http_front, 80, http_back. /haproxy?stats .



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HAProxy , .



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  • Roundrobin: . , . , .
  • Leastconn: . . , LDAP, SQL, TSE . ., , HTTP.
  • First: . , . maxconn, .
  • Source: IP- , , . , IP- , .


(layer 7)



— (layer 7), , - . , , URL.



HAProxy :



sudo vi /etc/haproxy/haproxy.cfg


:



frontend http_front
   bind *:80
   stats uri /haproxy?stats
   acl url_blog path_beg /blog
   use_backend blog_back if url_blog
   default_backend http_back

backend http_back
   balance roundrobin
   server server_name1 private_ip1:80 check
   server server_name2 private_ip2:80 check

backend blog_back
   server server_name3 private_ip3:80 check


ACL url_blog, , /blog. Use_backend , , url_blog, blog_back, .



: http_back, , , blog_back, example.com/blog.



HAProxy :



sudo systemctl restart haproxy


- , , , .





HAProxy , IP- , . stats uri .



http://load_balancer_public_ip/haproxy?stats


, , !





-, / . , , .



, , HTTP- . , HAProxy :



sudo systemctl status haproxy




, , , . , haproxy.cfg. username password - :



listen stats
   bind *:8181
   stats enable
   stats uri /
   stats realm Haproxy\ Statistics
   stats auth username:password


stats uri . , HAProxy.



sudo systemctl restart haproxy


, .



http://load_balancer_public_ip:8181


, - , IP - .



http://load_balancer_public_ip/


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: HAProxy



HAProxy! -. HAProxy, , , . , HAProxy, .



- , . , IP . IP- UpCloud.





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