获取 Hadoop 集群的一些配置值。

hdfs version 查看 Hadoop 集群的版本号。

如下是 hdfs 提供的命令：

  1. hdfs getconf
  2. hdfs getconf is utility for getting configuration information from the config file.
  3. hadoop getconf
  4.     [-namenodes]      gets list of namenodes in the cluster.
  5.     [-secondaryNameNodes]      gets list of secondary namenodes in the cluster.
  6.     [-backupNodes]      gets list of backup nodes in the cluster.
  7.     [-includeFile]      gets the include file path that defines the datanodes that can join the cluster.
  8.     [-excludeFile]      gets the exclude file path that defines the datanodes that need to decommissioned.
  9.     [-nnRpcAddresses]      gets the namenode rpc addresses
  10.     [-confKey [key]]      gets a specific key from the configuration

获取 defaultFS

hdfs getconf -confkey fs.defaultFs

获取 namenodes 节点信息

hdfs getconf -confkey namenodes

获取 namenode rpc 地址信息

用于客户端操作

hdfs getconf -confkey nnRpcAddresses

获取 dfs.nameservices

hdfs getconf -confkey dfs.nameservices

获取 dfs.ha.namenodes.xx

hdfs getconf -confkey dfs.ha.namenodes.xx

获取 dfs.namenode.rpc-address.xx.xxx

其中 nn1 为 ha 节点之一的别名。

RPC Adress 和 HTTP Adress 的区别

RPC 简单讲就是远程过程调用，远程意味着跨节点（机器）。

  • 客户端连接 Hadoop 集群使用 RPC 接口