Exception in thread "main" SettingsException[Failed to load settings from /usr/share/elasticsearch/config/elasticsearch.yml]; nested: AccessDeniedException[/usr/share/elasticsearch/config/elasticsearch.yml];
        at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:85)
        at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:100)
        at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:91)
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86)
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:127)
        at org.elasticsearch.cli.MultiCommand.execute(MultiCommand.java:91)
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:127)
        at org.elasticsearch.cli.Command.main(Command.java:90)
        at org.elasticsearch.common.settings.KeyStoreCli.main(KeyStoreCli.java:43)
Caused by: java.nio.file.AccessDeniedException: /usr/share/elasticsearch/config/elasticsearch.yml
        at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:90)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
        at java.base/sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:218)
        at java.base/java.nio.file.Files.newByteChannel(Files.java:375)
        at java.base/java.nio.file.Files.newByteChannel(Files.java:426)
        at java.base/java.nio.file.spi.FileSystemProvider.newInputStream(FileSystemProvider.java:420)
        at java.base/java.nio.file.Files.newInputStream(Files.java:160)
        at org.elasticsearch.common.settings.Settings$Builder.loadFromPath(Settings.java:1073)
        at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:83)
        ... 8 more
2021-02-01 02:15:10,832 main ERROR No Log4j 2 configuration file found. Using default configuration (logging only errors to the console), or user programmatically provided configurations. Set system property 'log4j2.debug' to show Log4j 2 internal initialization logging. See https://logging.apache.org/log4j/2.x/manual/configuration.html for instructions on how to configure Log4j 2
Exception in thread "main" SettingsException[Failed to load settings from /usr/share/elasticsearch/config/elasticsearch.yml]; nested: AccessDeniedException[/usr/share/elasticsearch/config/elasticsearch.yml];
        at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:85)
        at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:100)
        at org.elasticsearch.cli.EnvironmentAwareCommand.createEnv(EnvironmentAwareCommand.java:91)
        at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:86)
        at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:127)
        at org.elasticsearch.cli.Command.main(Command.java:90)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:126)
        at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:92)
Caused by: java.nio.file.AccessDeniedException: /usr/share/elasticsearch/config/elasticsearch.yml
        at java.base/sun.nio.fs.UnixException.translateToIOException(UnixException.java:90)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:106)
        at java.base/sun.nio.fs.UnixException.rethrowAsIOException(UnixException.java:111)
        at java.base/sun.nio.fs.UnixFileSystemProvider.newByteChannel(UnixFileSystemProvider.java:218)
        at java.base/java.nio.file.Files.newByteChannel(Files.java:375)
        at java.base/java.nio.file.Files.newByteChannel(Files.java:426)
        at java.base/java.nio.file.spi.FileSystemProvider.newInputStream(FileSystemProvider.java:420)
        at java.base/java.nio.file.Files.newInputStream(Files.java:160)
        at org.elasticsearch.common.settings.Settings$Builder.loadFromPath(Settings.java:1073)
        at org.elasticsearch.node.InternalSettingsPreparer.prepareEnvironment(InternalSettingsPreparer.java:83)
        ... 7 more

解决办法

相信有很多小伙伴都是这样启动elasticsearch的

docker run --name elasticsearch -p 9200:9200 -p 9300:9300 \
-e  "discovery.type=single-node" \
-e ES_JAVA_OPTS="-Xms64m -Xmx512m" \
-v /mydata/elasticsearch/config/elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml \
-v /mydata/elasticsearch/data:/usr/share/elasticsearch/data \
-v  /mydata/elasticsearch/plugins:/usr/share/elasticsearch/plugins \
-d elasticsearch:7.9.2

这里需要增加--privileged=true，也就是让docker有root权限启动容器

docker run --name elasticsearch --privileged=true -p 9200:9200 -p 9300:9300 \
-e  "discovery.type=single-node" \
-e ES_JAVA_OPTS="-Xms64m -Xmx512m" \
-v /mydata/elasticsearch/config/elasticsearch.yml:/usr/share/elasticsearch/config/elasticsearch.yml \
-v /mydata/elasticsearch/data:/usr/share/elasticsearch/data \
-v  /mydata/elasticsearch/plugins:/usr/share/elasticsearch/plugins \
-d elasticsearch:7.9.2

使用浏览器访问虚拟机9200端口，成功！！！

后续小伙伴可能还会出现网络连接问题，也就是kibana连接不上的问题，这里大家可以看这一片博文。或者一步到位。

网络连接问题：Docker安装kibana无法连接elasticsearch9200端口

安装elasticsearch和kibana一步到位：docker安装elasticsearch和kibana,一步到位