개발굼

nginx.conf 에서 upstream의 특정 server에  backup 만 추가해줌

http {
    ...(생략)...
    upstream tomcatGroup{
		server 127.0.0.1:8090 max_fails=3 fail_timeout=3s;
		server 127.0.0.1:8094 backup; //backup 추가
	}
    
    server {
        listen 80; 
		listen [::]:80;
        ...(생략)...
        location / {
        	proxy_pass http://tomcatGroup;
            ...(생략)...
         }
    } //end - server     
} //end - http

테스트 결과, AP1(Main) 이 다운되면 , AP2(Backup)으로 세션 전달됨

AP1이 재구동 시작되면, AP2의 연결이 끊기고 AP1이 완전히 구동될 때까지 대기 상태로 됨.

[참고] tomcat 클러스터링

AP1에서 AP2로 세션이 유지하기 위해서는 각 tomcat server.xml 및 web.xml에서 아래 설정 추가해야 함

https://tomcat.apache.org/tomcat-8.0-doc/cluster-howto.html

<?xml version="1.0" encoding="UTF-8"?>
<Server port="8005" shutdown="SHUTDOWN">
   ...(생략)...
  <Service name="Catalina">
  	...(생략)...  			   
	<Connector port="8090" protocol="HTTP/1.1"
		connectionTimeout="60000"
		URIEncoding="UTF-8"
		enableLookups="false"		
		redirectPort="443"
		disableUploadTimeout="true"
		maxThreads="500"
		minSpareThreads="100"
		maxSpareThreads="300"
		maxConnection="8192"
		maxParameterCount="1000000"
		compression="on"
		compressionMinSize="204800"
		noCompressionUserAgents="gozilla, traviata"
		compressableMimeType="text/html,text/plain,text/xml,text/css,text/javascript,application/javascript,application/json,application/octet-stream"
		useSendfile="false" />
       
    <Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcat8090">
        
        //방법 1.
        //아래 <Cluster> 태그만 주석 해제해도 동작함
        <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
        
        //방법 2.
        //아래 <Cluster> 태그는 관련 옵션 customize 할 때 사용
      	<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"
				 channelSendOptions="6"> 

		  <!-- <Manager className="org.apache.catalina.ha.session.BackupManager"
				   expireSessionsOnShutdown="false"
				   notifyListenersOnReplication="true"
				   mapSendOptions="6"/> -->
		  
		  <Manager className="org.apache.catalina.ha.session.DeltaManager"
				   expireSessionsOnShutdown="false"
				   notifyListenersOnReplication="true"/>
		  
		  <Channel className="org.apache.catalina.tribes.group.GroupChannel">
			<Membership className="org.apache.catalina.tribes.membership.McastService"
						address="228.0.0.4"
                        port="45564"
						frequency="500"
						dropTime="3000"/>
			<Receiver className="org.apache.catalina.tribes.transport.nio.NioReceiver"
					  address="auto"
                      //[중요] TCP port 4000~ 4100 설정가능
                      //같은 서버에서 tomcat이 여러개일 경우 해당 포트 각각 다르게 설정
					  port="4001"   
					  selectorTimeout="100"
					  maxThreads="6"/>

			<Sender className="org.apache.catalina.tribes.transport.ReplicationTransmitter">
			  <Transport className="org.apache.catalina.tribes.transport.nio.PooledParallelSender"/>
			</Sender>
			<Interceptor className="org.apache.catalina.tribes.group.interceptors.TcpFailureDetector"/>
			<Interceptor className="org.apache.catalina.tribes.group.interceptors.MessageDispatchInterceptor"/>
			<Interceptor className="org.apache.catalina.tribes.group.interceptors.ThroughputInterceptor"/>
		  </Channel>

		  <Valve className="org.apache.catalina.ha.tcp.ReplicationValve"
				 filter=".*\.gif|.*\.js|.*\.jpeg|.*\.jpg|.*\.png|.*\.htm|.*\.html|.*\.css|.*\.txt"/>

		  <Deployer className="org.apache.catalina.ha.deploy.FarmWarDeployer"
					tempDir="/tmp/war-temp/"
					deployDir="/tmp/war-deploy/"
					watchDir="/tmp/war-listen/"
					watchEnabled="false"/>

		  <ClusterListener className="org.apache.catalina.ha.session.ClusterSessionListener"/>
		</Cluster> -->	
        
		...(생략)... 
     </Engine>
  </Service>
</Server>

F12 - Application - Storage(Cookies)에서 JSESSIONID 확인

AP1 강제 종료하면 tomcat 로그에 

정보 [Membership-MemberDisappered.] 멤버 사라짐 메시지를 수신했습니다. 로그 확인

F12 - Application - Storage(Cookies)에서 JSESSIONID 다시 확인해보면 AP2 의 jvmRoute 값(tomcat8094)으로 변경된 것을 확인할 수 있음.

nginx : ver.1.20.1
tomcat: ver. 8.0

nginx를 이용 무중단 배포 시도 중 아래와 같이 .. 세션이 끊기는 현상 발생

nginx 설정(nginx.conf)은 

#user  nobody;
worker_processes  1;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;

#pid        logs/nginx.pid;

events {
    worker_connections  1024;
}

http {
    include       mime.types;
    default_type  application/octet-stream;

    sendfile        on;
    #tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;
	client_max_body_size 0;

    #gzip  on;

	upstream tomcatGroup{
		ip_hash;
		server 0.0.0.0:8088;
		server 0.0.0.0:8092;
	}

    server {
        #listen       8080; //8087
		listen 80; 
		listen [::]:80;
        server_name  (domain name);

        #charset koi8-r;

        #access_log  logs/host.access.log  main;

        location / {
            #root   html;
            #index  index.html index.htm;
			proxy_pass http://tomcatGroup;
			proxy_set_header X-Real-IP $remote_addr;
			proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
			#proxy_set_header X-Forwarded-Proto $scheme;
			#proxy_set_header X-NginX-Proxy true;
			#proxy_redirect off;
			charset utf-8;
			proxy_set_header Host $http_host;
			proxy_cookie_path ~*^/.* /;
			#add_header 'Access-Control-Allow-Origin' '*';
        }
    }
	...
}

upstream load balancing 할 IP 주소, port 입력 후 location에 proxy_pass에 upstream 지정해둠

//web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xml:xsi= ...

   <distributable/> //세션 공유를 위해 추가
 </web-app>

검색 결과 한가지 더 해줘야함. tomcat/conf/server.xml 에서

//server.xml
<?xml version='1.0' encoding='utf-8'?>
<Server port= ...
	...
	<Service name="Catalina">
	   <Engine name="Catalina" defaultHost="localhost" jvmRoute="tomcat8092">
	
         //주석 해제
         <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
           ...
       </Engine>
    </Service>
</Server>

 <Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>

이 태그 주석을 해제함.

아래 톰캣 공식 문서에 자세한 내용이 나와있음.

 tomcat:8092 startUp  -> Tomcat:8088 shutDown 후 다시 확인

참고:

https://tomcat.apache.org/tomcat-8.0-doc/cluster-howto.html

https://fliedcat.tistory.com/126

https://www.lesstif.com/java/tomcat-46366798.html