NoSQL数据库Cassandra运维工具nodetool连接远程节点

cassandra集群安装成功后使用nodetool命令连接本机节点正常，连接其他节点报错：connectexception 'connection refused (connection refused)'，查看nodetool连接的7199端口，监听0.0.0.0。
那为什么会连接不上呢？原因在于：cassandra启动是有两种模式，local和remote模式。可以在conf/cassandra-env.sh中查看和修改。

配置

cassandra默认使用local模式，配置如下：

if [ "x$LOCAL_JMX" = "x" ]; then
    LOCAL_JMX=yes
fi

# Specifies the default port over which Cassandra will be available for
# JMX connections.
# For security reasons, you should not expose this port to the internet.  Firewall it if needed.
JMX_PORT="7199"

if [ "$LOCAL_JMX" = "yes" ]; then
  JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.local.port=$JMX_PORT"
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
else
  JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.port=$JMX_PORT"
  # if ssl is enabled the same port cannot be used for both jmx and rmi so either
  # pick another value for this property or comment out to use a random port (though see CASSANDRA-7087 for origins)
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.rmi.port=$JMX_PORT"

  # turn on JMX authentication. See below for further options
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=true"

  # jmx ssl options
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl=true"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.need.client.auth=true"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.enabled.protocols=<enabled-protocols>"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.enabled.cipher.suites=<enabled-cipher-suites>"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.keyStore=/path/to/keystore"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.keyStorePassword=<keystore-password>"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.trustStore=/path/to/truststore"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.trustStorePassword=<truststore-password>"
fi

如果想使用remote模式，添加LOCAL_JMX=false和修改-Dcom.sun.management.jmxremote.authenticate=false，当然你可以开启加密方式。配置如下：

LOCAL_JMX=false
if [ "x$LOCAL_JMX" = "x" ]; then
    LOCAL_JMX=yes
fi

# Specifies the default port over which Cassandra will be available for
# JMX connections.
# For security reasons, you should not expose this port to the internet.  Firewall it if needed.
JMX_PORT="7199"

if [ "$LOCAL_JMX" = "yes" ]; then
  JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.local.port=$JMX_PORT"
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=false"
else
  JVM_OPTS="$JVM_OPTS -Dcassandra.jmx.remote.port=$JMX_PORT"
  # if ssl is enabled the same port cannot be used for both jmx and rmi so either
  # pick another value for this property or comment out to use a random port (though see CASSANDRA-7087 for origins)
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.rmi.port=$JMX_PORT"

  # turn on JMX authentication. See below for further options
  JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.authenticate=false"

  # jmx ssl options
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl=true"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.need.client.auth=true"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.enabled.protocols=<enabled-protocols>"
  #JVM_OPTS="$JVM_OPTS -Dcom.sun.management.jmxremote.ssl.enabled.cipher.suites=<enabled-cipher-suites>"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.keyStore=/path/to/keystore"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.keyStorePassword=<keystore-password>"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.trustStore=/path/to/truststore"
  #JVM_OPTS="$JVM_OPTS -Djavax.net.ssl.trustStorePassword=<truststore-password>"
fi

修改配置后，重启节点。一切ok