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Cisco ha tradotto questo documento utilizzando una combinazione di tecnologie automatiche e umane per offrire ai nostri utenti in tutto il mondo contenuti di supporto nella propria lingua. Si noti che anche la migliore traduzione automatica non sarà mai accurata come quella fornita da un traduttore professionista. Cisco Systems, Inc. non si assume alcuna responsabilità per l’accuratezza di queste traduzioni e consiglia di consultare sempre il documento originale in inglese (disponibile al link fornito).
Questo documento descrive ZooKeeper, che è essenzialmente un servizio centralizzato per sistemi distribuiti a un archivio valori chiave gerarchico. Viene utilizzato per fornire un servizio di configurazione distribuita, un servizio di sincronizzazione e un registro di denominazione per sistemi distribuiti di grandi dimensioni. L'architettura di ZooKeeper supporta l'alta disponibilità tramite servizi ridondanti. I clienti possono quindi chiedere a un altro capo ZooKeeper se il primo non risponde. I nodi ZooKeeper memorizzano i propri dati in uno spazio dei nomi gerarchico, in modo simile a un file system o a una struttura dati. I client possono leggere e scrivere nei nodi e in questo modo disporre di un servizio di configurazione condiviso. ZooKeeper può essere visto come un sistema di trasmissione atomico attraverso il quale gli aggiornamenti sono totalmente ordinati.
ZooKeeper offre queste caratteristiche principali:
In HX, esiste questa implementazione specifica:
Ad esempio, per un cluster a tre nodi - N/2=1,5 Arrotondato a 1 +1 =2 (è possibile tollerare un solo errore di nodo)
Ad esempio, per un cluster a cinque nodi - N/2=2,5 Arrotondato a 2 +1 =3 (sono tollerati solo gli errori di due nodi)
Poiché per un cluster ZK vengono eseguiti solo cinque nodi, è possibile tollerare un massimo di due errori di nodo per qualsiasi numero di nodi nel cluster. Ciò è vero per i nodi convergenti.
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# service exhibitor status
exhibitor start/running, process 4905
root@help:/var/log/springpath# ps -aux | grep -i exhibitor
root 12519 0.0 0.2 4690592 198892 ? Ssl May19 7:19 exhibitor -cp exhibitor.jar:/etc/exhibitor/ -Xmx256M -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/var/log/exhibitor_heap_dump_2019_05_19_22:19:48.hprof -Dlog4j.configuration=file:///etc/exhibitor/log4j.properties -Dspringpath.zkdownscript=/usr/share/springpath/storfs-misc/zkMonitor.sh -Djava.security.egd=file:/dev/./urandom -jar exhibitor.jar --hostname 10.197.252.100 -c file --fsconfigdir /etc/exhibitor --port 8180 --listenaddress 10.197.252.100
root@help:/var/log/springpath# pidof exhibitor
12519
Zookeeper dispone di una sintassi di comando di quattro lettere che consente di eseguire query su stato, elenchi di connessioni, numero di znode e così via.
Controllare lo stato di zookeeper sul nodo locale - (ruok ==> Continuare?. imok=>Sono OK.
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# echo ruok|nc localhost 2181
imok
Controllate se lo zookeeper è un puntale o un puntale.
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# echo srvr | nc localhost 2181
Zookeeper version: 3.4.6--1, built on 06/16/2015 22:50 GMT
Latency min/avg/max: 0/0/101
Received: 213128515
Sent: 213164119
Connections: 6
Outstanding: 0
Zxid: 0xa000301d0
Mode: leader
Node count: 17090
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# echo stat | nc localhost 2181
Zookeeper version: 3.4.6--1, built on 06/16/2015 22:50 GMT
Clients:
/192.168.5.161:56128[1](queued=0,recved=169146196,sent=169162634)
/192.168.5.161:38614[1](queued=0,recved=186015,sent=186017)
/192.168.5.164:44412[1](queued=0,recved=184398,sent=184399)
/192.168.5.164:44447[1](queued=0,recved=561168,sent=563034)
/127.0.0.1:60060[0](queued=0,recved=1,sent=0)
/192.168.5.161:58754[1](queued=0,recved=39233,sent=39261)
Latency min/avg/max: 0/0/101
Received: 213109927
Sent: 213145531
Connections: 6
Outstanding: 0
Zxid: 0xa000301d0
Mode: leader
Node count: 17090
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# echo mntr | nc localhost 2181
zk_version 3.4.6--1, built on 06/16/2015 22:50 GMT
zk_avg_latency 0
zk_max_latency 101
zk_min_latency 0
zk_packets_received 213148668
zk_packets_sent 213184272
zk_num_alive_connections 6
zk_outstanding_requests 0
zk_server_state leader
zk_znode_count 17090
zk_watch_count 4305
zk_ephemerals_count 20
zk_approximate_data_size 1831768
zk_open_file_descriptor_count 43
zk_max_file_descriptor_count 4096
zk_followers 3
zk_synced_followers 3
zk_pending_syncs 0
Controllare la configurazione di Zookeeper:
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# echo conf | nc localhost 2181
clientPort=2181
dataDir=/var/zookeeper/version-2
dataLogDir=/var/zookeeper/version-2
tickTime=3000
maxClientCnxns=60
minSessionTimeout=6000
maxSessionTimeout=60000
serverId=3
initLimit=10
syncLimit=3
electionAlg=3
electionPort=3888
quorumPort=2888
peerType=0
In caso di problemi nei servizi di Zookeeper, questi file di log consentono di trovare le tracce:
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# grep -i leader /var/log/zookeeper/zookeeper.log*
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,088 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Leader@60] - TCP NoDelay set to: true
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,099 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Leader@358] - LEADING - LEADER ELECTION TOOK - 354
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,120 [myid:3] - INFO [LearnerHandler-/192.168.5.164:36487:LearnerHandler@522] - Received NEWLEADER-ACK message from 0
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,120 [myid:3] - INFO [LearnerHandler-/192.168.5.163:43451:LearnerHandler@522] - Received NEWLEADER-ACK message from 1
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,120 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Leader@943] - Have quorum of supporters, sids: [ 0,1,3 ]; starting up and setting last processed zxid: 0x100000000
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,272 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 3 (n.leader), 0x0 (n.zxid), 0x1 (n.round), LOOKING (n.state), 2 (n.sid), 0x0 (n.peerEpoch) LEADING (my state)
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,291 [myid:3] - INFO [LearnerHandler-/192.168.5.162:48778:LearnerHandler@486] - Sending snapshot last zxid of peer is 0x0 zxid of leader is 0x100000000sent zxid of db as 0x100000000
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:59:26,298 [myid:3] - INFO [LearnerHandler-/192.168.5.162:48778:LearnerHandler@522] - Received NEWLEADER-ACK message from 2
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# grep -i warn /var/log/zookeeper/zookeeper.log*
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:46:30,354 [myid:] - WARN [main:QuorumPeerMain@113] - Either no config or no quorum defined in config, running in standalone mode
/var/log/zookeeper/zookeeper.log.7:2016-10-14 22:52:55,238 [myid:] - WARN [main:QuorumPeerMain@113] - Either no config or no quorum defined in config, running in standalone mode
root@SpringpathControllerMSH7NHXRFL:/var/log/zookeeper# grep -i goodbye /var/log/zookeeper/zookeeper.log*
/var/log/zookeeper/zookeeper.log.1:2017-01-23 03:55:50,429 [myid:3] - WARN [LearnerHandler-/192.168.5.163:44118:LearnerHandler@646] - ******* GOODBYE /192.168.5.163:44118 ********
/var/log/zookeeper/zookeeper.log.1:2017-01-24 23:30:14,956 [myid:3] - WARN [LearnerHandler-/192.168.5.164:44720:LearnerHandler@646] - ******* GOODBYE /192.168.5.164:44720 ********
/var/log/zookeeper/zookeeper.log.3:2016-12-01 23:45:22,510 [myid:3] - WARN [LearnerHandler-/192.168.5.164:44051:LearnerHandler@646] - ******* GOODBYE /192.168.5.164:44051 ********
/var/log/zookeeper/zookeeper.log.3:2016-12-08 00:36:37,752 [myid:3] - WARN [LearnerHandler-/192.168.5.162:46577:LearnerHandler@646] - ******* GOODBYE /192.168.5.162:46577 ********
/var/log/zookeeper/zookeeper.log.4:2016-11-22 23:45:30,957 [myid:3] - WARN [LearnerHandler-/192.168.5.163:49016:LearnerHandler@646] - ******* GOODBYE /192.168.5.163:49016 ********
/var/log/zookeeper/zookeeper.log.4:2016-11-23 00:03:59,397 [myid:3] - WARN [LearnerHandler-/192.168.5.164:45952:LearnerHandler@646] - ******* GOODBYE /192.168.5.164:45952 ********
/var/log/zookeeper/zookeeper.log.4:2016-12-01 22:51:00,538 [myid:3] - WARN [LearnerHandler-/192.168.5.163:45284:LearnerHandler@646] - ******* GOODBYE /192.168.5.163:45284 ********
/var/log/zookeeper/zookeeper.log.5:2016-11-10 23:39:47,477 [myid:3] - WARN [LearnerHandler-/192.168.5.163:43576:LearnerHandler@646] - ******* GOODBYE /192.168.5.163:43576 ********
/var/log/zookeeper/zookeeper.log.5:2016-11-11 00:49:39,782 [myid:3] - WARN [LearnerHandler-/192.168.5.164:35219:LearnerHandler@646] - ******* GOODBYE /192.168.5.164:35219 ********
Alcuni log di esempio - Registrazione di Zookeeper
2017-01-22 23:47:29,427 [myid:3] - INFO [Thread-2:QuorumCnxManager$Listener@504] - My election bind port: /192.168.5.161:3888
2017-01-22 23:47:29,435 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:QuorumPeer@714] - LOOKING
2017-01-22 23:47:29,438 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:FastLeaderElection@815] - New election. My id = 3, proposed zxid=0x9000a6b4d
2017-01-22 23:47:29,443 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 2 (n.leader), 0x800055ea0 (n.zxid), 0x1 (n.round), FOLLOWING (n.state), 0 (n.sid), 0x9 (n.peerEpoch) LOOKING (my state)
2017-01-22 23:47:29,444 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 2 (n.leader), 0x800055ea0 (n.zxid), 0x1 (n.round), FOLLOWING (n.state), 1 (n.sid), 0x9 (n.peerEpoch) LOOKING (my state)
2017-01-22 23:47:29,444 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 3 (n.leader), 0x9000a6b4d (n.zxid), 0x1 (n.round), LOOKING (n.state), 3 (n.sid), 0x9 (n.peerEpoch) LOOKING (my state)
2017-01-22 23:47:29,444 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 2 (n.leader), 0x800055ea0 (n.zxid), 0x1 (n.round), FOLLOWING (n.state), 1 (n.sid), 0x9 (n.peerEpoch) LOOKING (my state)
2017-01-22 23:47:29,445 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 2 (n.leader), 0x800055ea0 (n.zxid), 0x1 (n.round), LEADING (n.state), 2 (n.sid), 0x9 (n.peerEpoch) LOOKING (my state)
2017-01-22 23:47:29,445 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 2 (n.leader), 0x800055ea0 (n.zxid), 0x1 (n.round), FOLLOWING (n.state), 0 (n.sid), 0x9 (n.peerEpoch) LOOKING (my state)
2017-01-22 23:47:29,446 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:QuorumPeer@784] - FOLLOWING
2017-01-22 23:47:29,449 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Learner@86] - TCP NoDelay set to: true
2017-01-22 23:47:29,449 [myid:3] - INFO [WorkerReceiver[myid=3]:FastLeaderElection@597] - Notification: 1 (message format version), 2 (n.leader), 0x800055ea0 (n.zxid), 0x1 (n.round), LEADING (n.state), 2 (n.sid), 0x9 (n.peerEpoch) FOLLOWING (my state)
2017-01-22 23:47:29,660 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:zookeeper.version=3.4.6--1, built on 06/16/2015 22:50 GMT
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:host.name=SpringpathControllerMSH7NHXRFL
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.version=1.7.0_79
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.vendor=Oracle Corporation
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.home=/usr/lib/jvm/java-7-openjdk-amd64/jre
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.class.path=/usr/share/zookeeper/bin/../build/classes:/usr/share/zookeeper/bin/../build/lib/*.jar:/usr/share/zookeeper/bin/../lib/slf4j-log4j12-1.6.1.jar:/usr/share/zookeeper/bin/../lib/slf4j-api-1.6.1.jar:/usr/share/zookeeper/bin/../lib/netty-3.7.0.Final.jar:/usr/share/zookeeper/bin/../lib/log4j-1.2.16.jar:/usr/share/zookeeper/bin/../lib/jline-0.9.94.jar:/usr/share/zookeeper/bin/../zookeeper-3.4.6.jar:/usr/share/zookeeper/bin/../src/java/lib/*.jar:/usr/share/zookeeper/bin/../conf:
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib/x86_64-linux-gnu/jni:/lib/x86_64-linux-gnu:/usr/lib/x86_64-linux-gnu:/usr/lib/jni:/lib:/usr/lib
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.io.tmpdir=/tmp
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:java.compiler=
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:os.name=Linux
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:os.arch=amd64
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:os.version=3.2.0-58-generic
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:user.name=root
2017-01-22 23:47:29,661 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:user.home=/root
2017-01-22 23:47:29,662 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Environment@100] - Server environment:user.dir=/usr/share/zookeeper
2017-01-22 23:47:29,662 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:ZooKeeperServer@162] - Created server with tickTime 3000 minSessionTimeout 6000 maxSessionTimeout 60000 datadir /var/zookeeper/version-2 snapdir /var/zookeeper/version-2
2017-01-22 23:47:29,663 [myid:3] - INFO [QuorumPeer[myid=3]/0:0:0:0:0:0:0:0:2181:Follower@63] - FOLLOWING -
LEADER ELECTION TOOK - 226
root@SpringpathControllerMSH7NHXRFL:/var/log/springpath# cat zk-debug-storfs.log
2017-01-22 23:47:18,702:5866(0x7fd1f7ef5700):ZOO_INFO@check_events@1760: initiated connection to server [192.168.5.163:2181]
2017-01-22 23:47:18,704:5866(0x7fd1f7ef5700):ZOO_INFO@check_events@1807: session establishment complete on server [192.168.5.163:2181], sessionId=0x159165ff6310005, negotiated timeout=17001
2017-01-22 23:47:18,704:5866(0x7fd1f76f4700):ZOO_INFO@process_completions@2170: Calling a watcher for node s], type = s
2017-01-23 01:50:16,809:5866(0x7fd1f7ef5700):ZOO_ERROR@handle_socket_error_msg@1778: Socket [192.168.5.163:2181] zk retcode=-4, errno=112(Host is down): failed while receiving a server response
2017-01-23 01:50:16,818:5866(0x7fd1f76f4700):ZOO_INFO@process_completions@2170: Calling a watcher for node s], type = s
2017-01-23 01:50:16,818:5866(0x7fd1f7ef5700):ZOO_INFO@check_events@1760: initiated connection to server [192.168.5.164:2181]
2017-01-23 01:50:16,818:5866(0x7fd1f7ef5700):ZOO_ERROR@handle_socket_error_msg@1778: Socket [192.168.5.164:2181] zk retcode=-4, errno=112(Host is down): failed while receiving a server response
2017-01-23 01:50:17,819:5866(0x7fd1f7ef5700):ZOO_ERROR@handle_socket_error_msg@1740: Socket [192.168.5.162:2181] zk retcode=-4, errno=115(Operation now in progress): poll refused to accept read/write from the client
root@help:/var/log/springpath# cat zkEvents.log
INFO:ZkEvents:Send changes to listeners
INFO:EventDB:Received message{"timestamp": 1559200009008, "description": "Cluster policy compliance is satisfied", "id": "ClusterPolicyComplianceSatisfiedEvent"}
DEBUG:kazoo.client:Received EVENT: Watch(type=3, state=3, path=u'/zkEvents/lastModificationTime')
DEBUG:kazoo.client:Sending request(xid=42): GetData(path='/zkEvents/lastModificationTime', watcher=
DEBUG:kazoo.client:Received response(xid=42): ('{"timestamp": 1559200009009, "description": "Cluster is healthy", "id": "ClusterHealthNormalEvent"}', ZnodeStat(czxid=4294968021, mzxid=85899377486, ctime=1543045592975, mtime=1559200010730, version=465, cversion=0, aversion=0, ephemeralOwner=0, dataLength=99, numChildren=0, pzxid=4294968021))
INFO:ZkEvents:Version: 465, data: {"timestamp": 1559200009009, "description": "Cluster is healthy", "id": "ClusterHealthNormalEvent"}
INFO:ZkEvents:Send changes to listeners
INFO:EventDB:Received message{"timestamp": 1559200009009, "description": "
Cluster is healthy", "id": "ClusterHealthNormalEvent"}
INFO:EventDB:Client(38) disconnected
INFO:EventDB:New client connected and was given id 39
INFO:EventDB:Client(39) disconnected
root@SpringpathControllerPZTMTRSH7K:/var/log/springpath# tail exhibitor.log
05-20 05:28:52.223 INFO org.mortbay.log - Started SocketConnector@10.197.252.99:8180
05-20 05:29:20.106 INFO com.netflix.exhibitor.core.activity.ActivityLog - State: down
05-20 05:29:20.106 INFO com.netflix.exhibitor.core.activity.ActivityLog - Attempting to stop instance
05-20 05:29:20.106 INFO com.netflix.exhibitor.core.activity.ActivityLog - Attempting to start/restart ZooKeeper
05-20 05:29:20.328 INFO com.netflix.exhibitor.core.activity.ActivityLog - jps didn't find instance - assuming ZK is not running
05-20 05:29:20.347 INFO com.netflix.exhibitor.core.activity.ActivityLog - Process started via: /usr/share/zookeeper/bin/zkServer.sh
05-20 05:29:20.353 ERROR com.netflix.exhibitor.core.activity.ActivityLog - ZooKeeper Server: ZooKeeper JMX enabled by default
05-20 05:29:20.353 ERROR com.netflix.exhibitor.core.activity.ActivityLog - ZooKeeper Server: Using config: /usr/share/zookeeper/bin/../conf/zoo.cfg
05-20 05:29:21.366 INFO com.netflix.exhibitor.core.activity.ActivityLog - ZooKeeper Server: Starting zookeeper ... STARTED
05-20 05:29:50.128 INFO com.netflix.exhibitor.core.activity.ActivityLog - State: serving
In un pacchetto di supporto, questi sono file importanti da esaminare:
zookeeper.log /var/log/zookeeper zk-storfs.log /var/log/springpath echo_stat_|nc_localhost_2181.out under cmds_output