[Apache] Balancer > Linux/Apm

Apache Module mod_proxy_hcheck 

https://httpd.apache.org/docs/trunk/mod/mod_proxy_hcheck.html 

https://runebook.dev/ko/docs/apache_http_server/mod/mod_proxy_hcheck 

https://httpd.apache.org/docs/2.4/howto/reverse_proxy.html  //status=+H 

[httpd.conf] 

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LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_http_module modules/mod_proxy_http.so

LoadModule proxy_balancer_module modules/mod_proxy_balancer.so

LoadModule slotmem_shm_module modules/mod_slotmem_shm.so

LoadModule lbmethod_byrequests_module modules/mod_lbmethod_byrequests.so

LoadModule proxy_hcheck_module modules/mod_proxy_hcheck.so   <- Dynamic health check of Balancer members (workers) for mod_proxy

LoadModule watchdog_module modules/mod_watchdog.so            <- health check 

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[httpd-proxy.conf] - case1 ★★

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<IfModule proxy_module>

<IfModule proxy_http_module>

# Off : Reverse Proxy /  On :  Forward Proxy

      ProxyRequests Off

#프록시에 액세스할 수 있는 사용자를 제어

<Proxy *>

      Require all granted

</Proxy>

#서버 상태체크 동작 옵션설정

ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/}

ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/}

ProxyHCExpr gdown {%{REQUEST_STATUS} =~ /^[5]/}

<Proxy balancer://mycluster>        

  #http://192.168.0.11/status.php 체크(기본 30초마다)하여 Under maintenance 문자열이 포함되어 있으면 서버연결 비활성화(문자열 없으면 자동 서버 활성화됨) 

 BalancerMember http://192.168.0.11:80 loadfactor=1 retry=1 hcmethod=GET hcexpr=in_maint hcuri=/status.php     

 #http://192.168.0.35 체크(10초마다)하여 응답상태가 2xx, 3xx, 4xx 인지확인하여 밸런서 서버로 활성화/비활성화 결정

 BalancerMember http://192.168.0.35:80 loadfactor=1 retry=1 hcmethod=HEAD hcexpr=ok234 hcinterval=10  

 #http://192.168.0.45 TCP소켓 연결가능한지 체크(5초마다/3번 연결실패하면 비활성화)하여 밸런서 서버로 활성화/비활성화 결정

        BalancerMember http://192.168.0.45:80 hcmethod=TCP hcinterval=5 hcpasses=2 hcfails=3        

ProxySet lbmethod=byrequests

</Proxy>

ProxyPass / balancer://mycluster/

ProxyPassReverse / balancer://mycluster/

</IfModule>

</IfModule>

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[status.php]

<?php

echo "Under maintenance";

?>

[httpd-proxy.conf] - case2

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#

# Implements a proxy/gateway for Apache.

# # Required modules: mod_proxy, mod_proxy_http

#

<IfModule proxy_module>

<IfModule proxy_http_module>

ProxyHCExpr ok234 {%{REQUEST_STATUS} =~ /^[234]/}

ProxyHCExpr gdown {%{REQUEST_STATUS} =~ /^[5]/}

ProxyHCExpr in_maint {hc('body') !~ /Under maintenance/}

<Proxy balancer://mycluster>

       Order deny,allow

       Allow from all

       #Active node1

       BalancerMember http://192.168.0.21:80 loadfactor=1 retry=1 hcmethod=GET hcexpr=in_maint hcuri=/status.php      

       #Active node2

       BalancerMember http://192.168.0.25:80 loadfactor=1 retry=1 hcmethod=HEAD hcexpr=ok234 hcinterval=10       

       #Passive node

       BalancerMember http://192.168.0.45:80 status=+H retry=0

</Proxy> 

ProxyPass / balancer://mycluster/ stickysession=JSESSIONID|jsessionid

ProxyPassReverse /  http://192.168.0.21:80/

ProxyPassReverse /  http://192.168.0.25:80/

ProxyPassReverse /  http://192.168.0.45:80/

</IfModule>

</IfModule>

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