hadoop Web UI localhost:50070 can not open - hadoop3

Question

Ubuntu 16.04.1 LTS
Hadoop 3.3.1
I try to set up hadoop pseudo distributed mode referring to one network tutorial.and follow below steps.
Step 1:setting Hadoop
1.add below code to /etc/profile.
export HADOOP_HOME=/home/hadoop/hadoop
export HADOOP_MAPRED_HOME=$HADOOP_HOME
export HADOOP_COMMON_HOME=$HADOOP_HOME
export HADOOP_HDFS_HOME=$HADOOP_HOME
export YARN_HOME=$HADOOP_HOME
export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
export PATH=$PATH:$HADOOP_HOME/sbin:$HADOOP_HOME/bin
export HADOOP_INSTALL=$HADOOP_HOME
2.in $HADOOP_HOME/etc/hadoop/hadoop-env.sh,set
export JAVA_HOME=/opt/jdk1.8.0_261
core-site.xml:
<configuration>
<property>
<name>fs.default.name </name>
<value> hdfs://localhost:9000 </value>
</property>
</configuration>
hdfs-site.xml:
<configuration>
<property>
<name>dfs.replication</name>
<value>1</value>
</property>
<property>
<name>dfs.name.dir</name>
<value>file:///home/hadoop/hadoop/pseudo/hdfs/namenode</value>
</property>
<property>
<name>dfs.data.dir</name>
<value>file:///home/hadoop/hadoop/pseudo/hdfs/datanode</value>
</property>
</configuration>
yarn-site.xml:
<configuration>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
</configuration>
mapred-site.xml:
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>
Step 2:Verify Hadoop
1.$ hdfs namenode -format
2.
sudo apt-get install ssh
ssh-keygen -t rsa
ssh-copy-id hadoop#ubuntu
cd ~/hadoop/sbin
start-dfs.sh
3.start-yarn.sh
4.open http://localhost:50070/ in firefox on local machine.
Unable to connect
Firefox can't establish a connection to the server at localhost:50070.
The site could be temporarily unavailable or too busy. Try again in a few moments.
If you are unable to load any pages, check your computer's network connection.
If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.
5.open http://localhost:8088/ in firefox ,returns the same error of port 50070.
when I run jps command,it returns
hadoop#ubuntu:~/hadoop/sbin$ jps
32501 DataNode
32377 NameNode
32682 SecondaryNameNode
32876 Jps

Answer 1

Since Hadoop 3.0.0 - Alpha 1 there was a Change in the port configuration:
http://localhost:50070
was moved to
http://localhost:9870
see https://issues.apache.org/jira/browse/HDFS-9427