報錯信息：
./start-all.sh This script is Deprecated. Instead use start-dfs.sh and start-yarn.sh Starting namenodes on [master] master: starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-master.out spark-slave1: ssh: Could not resolve hostname spark-slave1: Name or service not known spark-slave2: ssh: Could not resolve hostname spark-slave2: Name or service not known Starting secondary namenodes [0.0.0.0] 0.0.0.0: starting secondarynamenode, logging to /usr/local/hadoop/logs/hadoop-root-secondarynamenode-master.out starting yarn daemons starting resourcemanager, logging to /usr/local/hadoop/logs/yarn--resourcemanager-master.out spark-slave2: ssh: Could not resolve hostname spark-slave2: Name or service not known spark-slave1: ssh: Could not resolve hostname spark-slave1: Name or service not known
分析：報錯信息大概意思是無法解析spark-slave1和spark-slave2主機名，我子節點的主機名明明是node1和node2，找了很久終於找到了問題所在
在slaves文件中
vim /usr/local/hadoop/etc/hadoop/slaves spark-slave1 spark-slave2
設置了默認的子節點主機名，改為自己的子節點即可
vim /usr/local/hadoop/etc/hadoop/slaves
node1
node2
然后重啟hadoop
./stop-all.sh //關閉 ./start-all.sh //啟動
然后發現就不報錯了，子節點啟動成功
@master:/usr/local/hadoop/sbin# jps 5698 ResourceManager 6403 Jps 5547 SecondaryNameNode 5358 NameNode
@node1:~# jps 885 Jps 744 NodeManager 681 DataNode
@node2:~# jps 914 Jps 773 NodeManager 710 DataNode
總結：hadoop下的slaves文件官方解釋為：集群里的一台機器被指定為 NameNode，另一台不同的機器被指定為JobTracker。這些機器是masters，余下的機器即作為DataNode也作為TaskTracker，這些機器是slaves，在slaves文件中列出所有slave的主機名或者IP地址，一行一個。 意思就是子節點主機名或ip，當然也可以設置為172之類的ip地址。