Hadoop多节点集群：异常：java.net.ConnectException：连接被拒绝

Question

我已经使用http://pingax.com/install-apache-hadoop-ubuntu-cluster-setup/设置了4个节点hadoop集群：

名称节点：node04数据节点：node01数据节点：node02数据节点：node03

我只能看到集群中有两个正在运行的节点（node01，node03）。 Node02的日志中包含以下错误消息：

2015-12-11 10:15:18,698 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: node04/127.17.0.224:9000. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-12-11 10:15:19,699 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: node04/127.17.0.224:9000. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)
2015-12-11 10:15:20,699 INFO org.apache.hadoop.ipc.Client: Retrying connect to server: node04/127.17.0.224:9000. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1000 MILLISECONDS)

每个节点/ etc / hosts包含以下内容：

127.0.0.1       localhost

127.17.0.221    node01
127.17.0.222    node02
127.17.0.223    node03
127.17.0.224    node04
# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

并且/ etc / hadoop / masters包含node04 ，/ etc / hadoop / slaves包含node01 node02和node03

您能帮我了解如何到达吗？ 谢谢！

Answer 1

执行以下操作：

1. 转到node02并运行telnet node04 9000和ping node04命令，以确认node02和node04之间存在连接
2. 在所有节点上，检查core-site.xml和hdfs-site.xml是否具有相同的内容

Answer 2

1. 检查ssh和sshd
2. 节点之间的ssh连接
3. 检查端口绑定详细信息（ Hadoop数据节点找不到NameNode ）

另请参阅https://wiki.apache.org/hadoop/ServerNotAvailable