hadoop start error:
Starting namenodes on [733ec62951d5]
733ec62951d5: ERROR: Cannot set priority of namenode process 868
Starting datanodes
localhost: ERROR: Cannot set priority of datanode process 974
2022-01-15 13:56:41,689 ERROR conf.Configuration: error parsing conf core-site.xml

It was noticed that it was caused by an error in the core-site.xml configuration file. After modification, the correct core-site.xml configuration file is as follows.

?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
        <name>fs.defaultFS</name>
        <value>hdfs://172.17.0.3:9000</value>
</property>
</configuration>

Correct HDFS site The XML configuration file is as follows:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
  Licensed under the Apache License, Version 2.0 (the "License");
  you may not use this file except in compliance with the License.
  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License. See accompanying LICENSE file.
-->

<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
    <name>dfs.replication</name>
    <value>1</value>
</property>
</configuration>