httpd mod_proxy 와 tomcat lb 설정에 따른 load balancer 구현

[추가 - httpd + tomcat]

- 그냥 tomcat 을 l4 에 바로 연결 하면 되는데 요구사항에 따라 아래와 같이 할 수도 있습니다.

<VirtualHost www.xxxx.com:80>

    ServerAdmin admin@xxxx.com

    DocumentRoot "/home/shop/app/httpd/htdocs"

    ServerName www.xxxx.com

    ServerAlias www.xxxx.com

    ErrorLog "/home/shop/app/httpd/logs/error.log"

    CustomLog "/home/shop/app/httpd/logs/access.log" common

ProxyRequests On

ProxyPass /admin balancer://shopAdmin

ProxyPass /admin/resources balancer://shopAdminStatic

<Proxy balancer://shopAdmin>

BalancerMember ajp://192.168.1.1:8009/admin loadfactor=1 route=shopAdmin1

BalancerMember ajp://192.168.1.2:8009/admin loadfactor=1 route=shopAdmin2

ProxySet lbmethod=byrequests

</Proxy>

<Proxy balancer://shopAdminStatic>

BalancerMember http://192.168.1.1:8080/admin/resources loadfactor=1 route=shopAdminStatic1

BalancerMember http://192.168.1.1:8080/admin/resources loadfactor=1 route=shopAdminStatic2

ProxySet lbmethod=byrequests

</Proxy>

<Directory "/home/shop/app/httpd/htdocs">

Options FollowSymLinks

AllowOverride None

Order allow,deny

Allow from All

</Directory>

</VirtualHost>

[httpd 의 mod_proxy 를 이용한 load balancing 구현]

<VirtualHost dev.session-cluster.com:80>

    ServerAdmin howook.jeong@nhn.com

    DocumentRoot "D:\Application\httpd\htdocs\session_cluster\web"

    ServerName dev.session-cluster.com

    ServerAlias dev.session-cluster.com

    ErrorLog "D:/Application/httpd/logs/dev.session-cluster.com-error.log"

    CustomLog "D:/Application/httpd/logs/dev.session-cluster.com-access.log" common

DirectoryIndex index.html index.jsp

ProxyPass /cluster balancer://mycluster

ProxyPassReverse /cluster ajp://10.67.8.113:8009/

ProxyPassReverse /cluster ajp://10.67.8.113:8109/

<Proxy balancer://mycluster>

BalancerMember ajp://10.67.8.113:8009/ loadfactor=1 route=tomcat1

BalancerMember ajp://10.67.8.113:8109/ loadfactor=1 route=tomcat2

ProxySet lbmethod=byrequests

</Proxy>

<Directory "D:\Application\httpd\htdocs\session_cluster\web">

Options FollowSymLinks

AllowOverride None

Order allow,deny

Allow from All

</Directory>

</VirtualHost>

※ ProxyRequests Off 를 설정 하게 되면 ProxySet lbmethod=byrequests 가 동작 하지 않습니다.
※ 위와 같이 적용했을 경우 mod_jk.so 를 통한 연결은 필요가 없습니다. 이유는 mod_proxy_ajp.so 를 이용해서 연결을 하기 때문 입니다.

[참고자료]
-  http://httpd.apache.org/docs/2.2/mod/mod_proxy.html 

Parameter	Default	Description
lbmethod	byrequests	Balancer load-balance method. Select the load-balancing scheduler method to use. Either byrequests, to perform weighted request counting, bytraffic, to perform weighted traffic byte count balancing, or bybusyness (Apache HTTP Server 2.2.10 and later), to perform pending request balancing. Default is byrequests.
maxattempts	One less than the number of workers, or 1 with a single worker.	Maximum number of failover attempts before giving up.
nofailover	Off	If set to On the session will break if the worker is in error state or disabled. Set this value to On if backend servers do not support session replication.
stickysession	-	Balancer sticky session name. The value is usually set to something like JSESSIONID or PHPSESSIONID, and it depends on the backend application server that support sessions. If the backend application server uses different name for cookies and url encoded id (like servlet containers) use | to to separate them. The first part is for the cookie the second for the path.
scolonpathdelim	Off	If set to On the semi-colon character ';' will be used as an additional sticky session path deliminator/separator. This is mainly used to emulate mod_jk's behavior when dealing with paths such as JSESSIONID=6736bcf34;foo=aabfa
timeout	0	Balancer timeout in seconds. If set this will be the maximum time to wait for a free worker. Default is not to wait.
failonstatus	-	A single or comma-separated list of HTTP status codes. If set this will force the worker into error state when the backend returns any status code in the list. Worker recovery behaves the same as other worker errors. Available with Apache HTTP Server 2.2.17 and later.

※ 이전 글 Tomcat Sessoin Clustering 과 연관 해서 load balance 를 적용해 보시는 것도 성능에 도움이 될 수 있습니다.