启动 NameNode 和 DataNode
登录 hadoop1，执行下面命令：
start-dfs.sh
执行结果如下：
Starting namenodes on [hadoop1]
上一次登录：一 9月 20 19:47:49 CST 2021从 192.168.58.1pts/0 上
Starting datanodes
上一次登录：一 9月 20 21:49:22 CST 2021pts/0 上
hadoop3: WARNING: /program/hadoop-3.0.3//logs does not exist. Creating.
hadoop2: WARNING: /program/hadoop-3.0.3//logs does not exist. Creating.
Starting secondary namenodes [hadoop3]
上一次登录：一 9月 20 21:49:25 CST 2021pts/0 上
启动 namenodes 在 hadoop1
启动 datanodes 在 hadoop3、hadoop2
启动 secondary 在 hadoop3
停止 NameNode 和 DataNode
stop-dfs.sh
启动 yarn
注意： 因为 resourcemanager 部署在 hadoop2 上，所以要登录 hadoop2
执行下面命令：
start-yarn.sh
报错
如果不在 hadoop2 上启动 yarn，在 logs/hadoop-root-resourcemanager-hadoop2.log 报错如下：
java.net.BindException: Port in use: hadoop102:8088
at org.apache.hadoop.http.HttpServer2.constructBindException(HttpServer2.java:1140)
at org.apache.hadoop.http.HttpServer2.bindForSinglePort(HttpServer2.java:1162)
at org.apache.hadoop.http.HttpServer2.openListeners(HttpServer2.java:1221)
at org.apache.hadoop.http.HttpServer2.start(HttpServer2.java:1076)
at org.apache.hadoop.yarn.webapp.WebApps$Builder.start(WebApps.java:408)
at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.startWepApp(ResourceManager.java:1137)
at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.serviceStart(ResourceManager.java:1245)
at org.apache.hadoop.service.AbstractService.start(AbstractService.java:194)
at org.apache.hadoop.yarn.server.resourcemanager.ResourceManager.main(ResourceManager.java:1446)
Caused by: java.net.BindException: 无法指定被请求的地址
at sun.nio.ch.Net.bind0(Native Method)
at sun.nio.ch.Net.bind(Net.java:433)
at sun.nio.ch.Net.bind(Net.java:425)
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223)
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:317)
at org.apache.hadoop.http.HttpServer2.bindListener(HttpServer2.java:1127)
at org.apache.hadoop.http.HttpServer2.bindForSinglePort(HttpServer2.java:1158)
... 7 more
错误提示 8088 端口占用，但经过查找，没有占用该端口
停止 yarn
stop-yarn.sh
jps查看是否启动成功
jps是jdk命令
登录 hadoop1
jps
显示如下：
39041 DataNode
42165 Jps
42006 NodeManager
38860 NameNode
表示启动成功
登录 hadoop2
jps
显示如下：
15713 DataNode
27858 Jps
27463 NodeManager
27292 ResourceManager
表示启动成功
登录 hadoop3
jps
显示如下：
5265 Jps
3893 SecondaryNameNode
5109 NodeManager
3789 DataNode
表示启动成功