Apache ZooKeeper
- ZooKeeper is a high-performance coordination service for distributed applications.
ZooKeeper 는 분산어플리케이션을 위한 고성능 조정서비스 입니다.
ZooKeeper is a centralized service for maintaining configuration information, naming, providing distributed synchronization, and providing group services. All of these kinds of services are used in some form or another by distributed applications. Each time they are implemented there is a lot of work that goes into fixing the bugs and race conditions that are inevitable. Because of the difficulty of implementing these kinds of services, applications initially usually skimp on them ,which make them brittle in the presence of change and difficult to manage. Even when done correctly, different implementations of these services lead to management complexity when the applications are deployed.
분산환경에서 운영되는 서비스들을 유지보수 할 때, 중앙관리를 위한 서비스를 제공하는것이 Zookeeper 의 목적인것 같음. Hadoop 과 같은 수많은 시스템으로 구성된 분산환경에서, 버그를 수정한다던지 설정을 초기화해야 한다던지의 업무를 해야 한다면 많은 노력이 필요할 것이다. 이때 이러한 역할을 중앙에서 관리할 수 있다면 해서 시작된것이 프로젝트의 시작인것 같음. 아무튼 분산환경에 배포된 어플리케이션을 관리하기가 어려운 점을 보완하기 위한 서비스를 제공하는것이 ZooKeeper 이라 이해됨.
CentOS 6.3 을 기준으로 ZooKeeper 3.4.4 설치 및 테스트(Single Node)를 진행함
# 1. 소스 다운로드 및 압축 해제 [luvu@vm srv]$ wget http://apache.mirror.cdnetworks.com/zookeeper/zookeeper-3.4.4/zookeeper-3.4.4.tar.gz [luvu@vm srv]$ tar -xvf ./zookeeper-3.4.4.tar.gz [luvu@vm srv]$ mv zookeeper-3.4.4.tar.gz zookeeper # 2. 설정파일 복사 및 작성 [luvu@vm zookeeper]$ vi cp conf/zoo_sample.cfg zoo.cfg [luvu@vm zookeeper]$ vi conf/zoo.cfg # The number of milliseconds of each tick tickTime=2000 # The number of ticks that the initial # synchronization phase can take ## initLimit=10 # The number of ticks that can pass between # sending a request and getting an acknowledgement ## syncLimit=5 # the directory where the snapshot is stored. # do not use /tmp for storage, /tmp here is just # example sakes. dataDir=/srv/zookeeper/data # the port at which the clients will connect clientPort=2181 # # Be sure to read the maintenance section of the # administrator guide before turning on autopurge. # # http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance # # The number of snapshots to retain in dataDir #autopurge.snapRetainCount=3 # Purge task interval in hours # Set to "0" to disable auto purge feature #autopurge.purgeInterval=1 # 3. 서버 실행 [luvu@vm zookeeper]$ bin/zkServer.sh start JMX enabled by default Using config: /srv/zookeeper/bin/../conf/zoo.cfg Starting zookeeper ... STARTED # 4. 방화벽 포트 해제 및 클라이언트 실행 [luvu@vm zookeeper]$ iptables -I INPUT -p tcp --dport 2181 -j ACCEPT [luvu@vm zookeeper]$ service iptables save [luvu@vm zookeeper]$ service iptables restart [luvu@vm zookeeper]$ bin/zkCli.sh -server 127.0.0.1:2181 Connecting to 127.0.0.1:2181 2012-11-02 20:00:54,914 [myid:] - INFO [main:Environment@100] - Client environment:zookeeper.version=3.4.4-1386507, built on 09/17/2012 08:33 GMT 2012-11-02 20:00:54,916 [myid:] - INFO [main:Environment@100] - Client environment:host.name=localhost 2012-11-02 20:00:54,916 [myid:] - INFO [main:Environment@100] - Client environment:java.version=1.6.0_35 2012-11-02 20:00:54,919 [myid:] - INFO [main:Environment@100] - Client environment:java.vendor=Sun Microsystems Inc. 2012-11-02 20:00:54,919 [myid:] - INFO [main:Environment@100] - Client environment:java.home=/usr/local/lib64/jdk1.6.0_35/jre 2012-11-02 20:00:54,920 [myid:] - INFO [main:Environment@100] - Client environment:java.class.path=/srv/zookeeper/bin/../build/classes:/srv/zookeeper/bin/../build/lib/*.jar:/srv/zookeeper/bin/../lib/slf4j-log4j12-1.6.1.jar:/srv/zookeeper/bin/../lib/slf4j-api-1.6.1.jar:/srv/zookeeper/bin/../lib/netty-3.2.2.Final.jar:/srv/zookeeper/bin/../lib/log4j-1.2.15.jar:/srv/zookeeper/bin/../lib/jline-0.9.94.jar:/srv/zookeeper/bin/../zookeeper-3.4.4.jar:/srv/zookeeper/bin/../src/java/lib/*.jar:/srv/zookeeper/bin/../conf:/usr/local/lib64/jdk1.6.0_35/jre/ext:/usr/local/lib64/jdk1.6.0_35/lib/tools.jar 2012-11-02 20:00:54,920 [myid:] - INFO [main:Environment@100] - Client environment:java.library.path=/usr/local/lib64/jdk1.6.0_35/jre/lib/amd64/server:/usr/local/lib64/jdk1.6.0_35/jre/lib/amd64:/usr/local/lib64/jdk1.6.0_35/jre/../lib/amd64:/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib 2012-11-02 20:00:54,921 [myid:] - INFO [main:Environment@100] - Client environment:java.io.tmpdir=/tmp 2012-11-02 20:00:54,922 [myid:] - INFO [main:Environment@100] - Client environment:java.compiler=2012-11-02 20:00:54,922 [myid:] - INFO [main:Environment@100] - Client environment:os.name=Linux 2012-11-02 20:00:54,922 [myid:] - INFO [main:Environment@100] - Client environment:os.arch=amd64 2012-11-02 20:00:54,923 [myid:] - INFO [main:Environment@100] - Client environment:os.version=2.6.32-279.9.1.el6.x86_64 2012-11-02 20:00:54,923 [myid:] - INFO [main:Environment@100] - Client environment:user.name=luvu 2012-11-02 20:00:54,923 [myid:] - INFO [main:Environment@100] - Client environment:user.home=/home/luvu 2012-11-02 20:00:54,931 [myid:] - INFO [main:Environment@100] - Client environment:user.dir=/srv/zookeeper-3.4.4 2012-11-02 20:00:54,932 [myid:] - INFO [main:ZooKeeper@433] - Initiating client connection, connectString=127.0.0.1:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@66edc3a2 Welcome to ZooKeeper! # 5. 도움말 [zk: 127.0.0.1:2181(CONNECTED) 0] help ZooKeeper -server host:port cmd args connect host:port get path [watch] ls path [watch] set path data [version] rmr path delquota [-n|-b] path quit printwatches on|off create [-s] [-e] path data acl stat path [watch] close ls2 path [watch] history listquota path setAcl path acl getAcl path sync path redo cmdno addauth scheme auth delete path [version] setquota -n|-b val path [zk: 127.0.0.1:2181(CONNECTED) 1] # 6. ls 커맨드 [zk: 127.0.0.1:2181(CONNECTED) 1] ls / [zookeeper] # 7. 새로운 znode 생성 및 myTest String 생성 [zk: 127.0.0.1:2181(CONNECTED) 2] create /playforum_test myTest Created /playforum_test [zk: 127.0.0.1:2181(CONNECTED) 3] ls / [playforum_test, zookeeper] # 8. playforum_test znode 데이터 확인 [zk: 127.0.0.1:2181(CONNECTED) 4] get /playforum_test myTest cZxid = 0x13 ctime = Fri Nov 02 20:03:55 KST 2012 mZxid = 0x13 mtime = Fri Nov 02 20:03:55 KST 2012 pZxid = 0x13 cversion = 0 dataVersion = 0 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 6 numChildren = 0 # 9. 데이터 변경 [zk: 127.0.0.1:2181(CONNECTED) 5] set /playforum_test junk cZxid = 0x13 ctime = Fri Nov 02 20:03:55 KST 2012 mZxid = 0x14 mtime = Fri Nov 02 20:04:20 KST 2012 pZxid = 0x13 cversion = 0 dataVersion = 1 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 4 numChildren = 0 # 10. 데이터 삭제 [zk: 127.0.0.1:2181(CONNECTED) 6] delete /playforum_test [zk: 127.0.0.1:2181(CONNECTED) 7] ls / [zookeeper] [zk: 127.0.0.1:2181(CONNECTED) 8]
참고사항
1. JDK 1.7.X 에서 session timed out 오류가 있었음
-> JDK 1.6.X 로 변경시 정상동작 확인
참고문서
http://zookeeper.apache.org
https://cwiki.apache.org/confluence/display/ZOOKEEPER/Index
http://www.mimul.com/pebble/default/2010/12/30/1293709016460.html
http://www.xenomity.com/112
http://bench87.tistory.com/228
http://ir.bagesoft.com/664
