我是cassandra apache的新手。在教程视频中，它表示输入bin / nodetools状态以检查节点的状态，但是当我尝试输入它时。终端返回
Failed to connect to '127.0.0.1:7199' - ConnectException: 'Connection
refused (Connection refused)'.
我尝试将JVM_OPTS更改为＆＃34; $ JVM_OPTS -Djava.rmi.server.hostname = localhost＆＃34;在cassandra-env.sh 但仍然无法连接。 我该怎么做才能解决这个错误？
Debug.logs
DEBUG [main] 2017-01-21 13:57:48,095 ColumnFamilyStore.java:881 - Enqueuing flush of local: 38.338KiB (0%) on-heap, 0.000KiB (0%) off-heap
DEBUG [PerDiskMemtableFlushWriter_0:1] 2017-01-21 13:57:48,167 Memtable.java:435 - Writing Memtable-local@858986260(8.879KiB serialized bytes, 1 ops, 0%/0% of on/off-heap limit), flushed range = (min(-9223372036854775808), max(9223372036854775807)]
DEBUG [PerDiskMemtableFlushWriter_0:1] 2017-01-21 13:57:48,168 Memtable.java:464 - Completed flushing /usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-56-big-Data.db (5.367KiB) for commitlog position CommitLogPosition(segmentId=1484978256521, position=32861)
DEBUG [MemtableFlushWriter:1] 2017-01-21 13:57:48,471 ColumnFamilyStore.java:1184 - Flushed to [BigTableReader(path='/usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-56-big-Data.db')] (1 sstables, 9.527KiB), biggest 9.527KiB, smallest 9.527KiB
DEBUG [CompactionExecutor:1] 2017-01-21 13:57:48,472 CompactionTask.java:150 - Compacting (896b3470-df9e-11e6-9508-7dc463a45cc9) [/usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-53-big-Data.db:level=0, /usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-54-big-Data.db:level=0, /usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-55-big-Data.db:level=0, /usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-56-big-Data.db:level=0, ]
DEBUG [main] 2017-01-21 13:57:48,539 StorageService.java:2084 - Node localhost/127.0.0.1 state NORMAL, token [-1035692197905104867, -1103547951527719073, -1136980347732340590, -1150272208899529050, -1184340318934652250, -1251847845785777189, -1355083122390358187,
INFO [main] 2017-01-21 13:57:48,539 StorageService.java:2087 - Node localhost/127.0.0.1 state jump to NORMAL
DEBUG [main] 2017-01-21 13:57:48,545 StorageService.java:1336 - NORMAL
DEBUG [PendingRangeCalculator:1] 2017-01-21 13:57:48,575 PendingRangeCalculatorService.java:66 - finished calculation for 3 keyspaces in 19ms
INFO [main] 2017-01-21 13:57:49,125 NativeTransportService.java:70 - Netty using native Epoll event loop
DEBUG [CompactionExecutor:1] 2017-01-21 13:57:49,286 CompactionTask.java:230 - Compacted (896b3470-df9e-11e6-9508-7dc463a45cc9) 4 sstables to [/usr/lib/cassandra/apache-cassandra-3.9/data/data/system/local-7ad54392bcdd35a684174e047860b377/mc-57-big,] to level=0. 9.869KiB to 4.938KiB (~50% of original) in 812ms. Read Throughput = 12.145KiB/s, Write Throughput = 6.077KiB/s, Row Throughput = ~2/s. 4 total partitions merged to 1. Partition merge counts were {4:1, }
INFO [main] 2017-01-21 13:57:49,368 Server.java:159 - Using Netty Version: [netty-buffer=netty-buffer-4.0.39.Final.38bdf86, netty-codec=netty-codec-4.0.39.Final.38bdf86, netty-codec-haproxy=netty-codec-haproxy-4.0.39.Final.38bdf86, netty-codec-http=netty-codec-http-4.0.39.Final.38bdf86, netty-codec-socks=netty-codec-socks-4.0.39.Final.38bdf86, netty-common=netty-common-4.0.39.Final.38bdf86, netty-handler=netty-handler-4.0.39.Final.38bdf86, netty-tcnative=netty-tcnative-1.1.33.Fork19.fe4816e, netty-transport=netty-transport-4.0.39.Final.38bdf86, netty-transport-native-epoll=netty-transport-native-epoll-4.0.39.Final.38bdf86, netty-transport-rxtx=netty-transport-rxtx-4.0.39.Final.38bdf86, netty-transport-sctp=netty-transport-sctp-4.0.39.Final.38bdf86, netty-transport-udt=netty-transport-udt-4.0.39.Final.38bdf86]
INFO [main] 2017-01-21 13:57:49,369 Server.java:160 - Starting listening for CQL clients on localhost/127.0.0.1:9042 (unencrypted)...
INFO [main] 2017-01-21 13:57:49,429 CassandraDaemon.java:521 - Not starting RPC server as requested. Use JMX (StorageService->startRPCServer()) or nodetool (enablethrift) to start it
答案 0 :(得分：5)
答案 1 :(得分：2)
查找并取消注释以下行 JVM_OPTS =“$ JVM_OPTS -Djava.rmi.server.hostname =” 至 JVM_OPTS =“$ JVM_OPTS -Djava.rmi.server.hostname = 127.0.0.1”
如果您在启动cassandra时遇到任何困难，请删除datastax的提交日志，
C:\Program Files\DataStax-DDC\data\commitlog
答案 2 :(得分：0)
Connection refused可能有多种原因，最常见的原因是要连接的应用程序不存在。使用
sudo service cassandra status # exit by pressing 'q'
如果以粗体显示 active (exited) ，则Cassandra甚至无法运行！
检查Cassandra的日志中是否有错误消息：
grep -A2 ERROR /var/log/cassandra/system.log
在htop之后观看sudo service cassandra restart －如果它填满了所有可用的内存，Cassandra将死而没有错误消息。在我的EC2实例上，一个空的Cassandra占用约1.3 GB的RAM，对于t2.nano或t2.micro实例来说，这太少了。
答案 3 :(得分：-1)
检查你的系统内存我遇到了同样的问题，但在增加RAM 4GB之后它正常工作。