All hadoop commands are invoked by the bin/hadoop script. Running the hadoop script without any arguments prints the description for all commands.
Usage: hadoop [--config confdir] [--loglevel loglevel] [COMMAND] [GENERIC_OPTIONS] [COMMAND_OPTIONS]
| FIELD | Description |
|---|---|
| --config confdir | Overwrites the default Configuration directory. Default is ${HADOOP_HOME}/conf. |
| --loglevel loglevel | Overwrites the log level. Valid log levels are FATAL, ERROR, WARN, INFO, DEBUG, and TRACE. Default is INFO. |
| GENERIC_OPTIONS | The common set of options supported by multiple commands. |
| COMMAND_OPTIONS | Various commands with their options are described in this documention for the Hadoop common sub-project. HDFS and YARN are covered in other documents. |
Many subcommands honor a common set of configuration options to alter their behavior:
| GENERIC_OPTION | Description |
|---|---|
| -archives <comma separated list of archives> | Specify comma separated archives to be unarchived on the compute machines. Applies only to job. |
| -conf <configuration file> | Specify an application configuration file. |
| -D <property>=<value> | Use value for given property. |
| -files <comma separated list of files> | Specify comma separated files to be copied to the map reduce cluster. Applies only to job. |
| -fs <file:///> or <hdfs://namenode:port> | Specify default filesystem URL to use. Overrides ‘fs.defaultFS’ property from configurations. |
| -jt <local> or <resourcemanager:port> | Specify a ResourceManager. Applies only to job. |
| -libjars <comma seperated list of jars> | Specify comma separated jar files to include in the classpath. Applies only to job. |
All of these commands are executed from the hadoop shell command. They have been broken up into User Commands and Administration Commands.
Commands useful for users of a hadoop cluster.
Creates a hadoop archive. More information can be found at Hadoop Archives Guide.
Usage: hadoop checknative [-a] [-h]
| COMMAND_OPTION | Description |
|---|---|
| -a | Check all libraries are available. |
| -h | print help |
This command checks the availability of the Hadoop native code. See Native Libaries for more information. By default, this command only checks the availability of libhadoop.
Usage: hadoop classpath [--glob |--jar <path> |-h |--help]
| COMMAND_OPTION | Description |
|---|---|
| --glob | expand wildcards |
| --jar path | write classpath as manifest in jar named path |
| -h, --help | print help |
Prints the class path needed to get the Hadoop jar and the required libraries. If called without arguments, then prints the classpath set up by the command scripts, which is likely to contain wildcards in the classpath entries. Additional options print the classpath after wildcard expansion or write the classpath into the manifest of a jar file. The latter is useful in environments where wildcards cannot be used and the expanded classpath exceeds the maximum supported command line length.
Usage: hadoop credential <subcommand> [options]
| COMMAND_OPTION | Description |
|---|---|
| create alias [-provider provider-path] [-strict] [-value credential-value] | Prompts the user for a credential to be stored as the given alias. The hadoop.security.credential.provider.path within the core-site.xml file will be used unless a -provider is indicated. The -strict flag will cause the command to fail if the provider uses a default password. Use -value flag to supply the credential value (a.k.a. the alias password) instead of being prompted. |
| delete alias [-provider provider-path] [-strict] [-f] | Deletes the credential with the provided alias. The hadoop.security.credential.provider.path within the core-site.xml file will be used unless a -provider is indicated. The -strict flag will cause the command to fail if the provider uses a default password. The command asks for confirmation unless -f is specified |
| list [-provider provider-path] [-strict] | Lists all of the credential aliases The hadoop.security.credential.provider.path within the core-site.xml file will be used unless a -provider is indicated. The -strict flag will cause the command to fail if the provider uses a default password. |
Command to manage credentials, passwords and secrets within credential providers.
The CredentialProvider API in Hadoop allows for the separation of applications and how they store their required passwords/secrets. In order to indicate a particular provider type and location, the user must provide the hadoop.security.credential.provider.path configuration element in core-site.xml or use the command line option -provider on each of the following commands. This provider path is a comma-separated list of URLs that indicates the type and location of a list of providers that should be consulted. For example, the following path: user:///,jceks://file/tmp/test.jceks,jceks://hdfs@nn1.example.com/my/path/test.jceks
indicates that the current user’s credentials file should be consulted through the User Provider, that the local file located at /tmp/test.jceks is a Java Keystore Provider and that the file located within HDFS at nn1.example.com/my/path/test.jceks is also a store for a Java Keystore Provider.
When utilizing the credential command it will often be for provisioning a password or secret to a particular credential store provider. In order to explicitly indicate which provider store to use the -provider option should be used. Otherwise, given a path of multiple providers, the first non-transient provider will be used. This may or may not be the one that you intended.
Providers frequently require that a password or other secret is supplied. If the provider requires a password and is unable to find one, it will use a default password and emit a warning message that the default password is being used. If the -strict flag is supplied, the warning message becomes an error message and the command returns immediately with an error status.
Example: hadoop credential list -provider jceks://file/tmp/test.jceks
Copy file or directories recursively. More information can be found at Hadoop DistCp Guide.
This command is documented in the File System Shell Guide. It is a synonym for hdfs dfs when HDFS is in use.
Usage: hadoop jar <jar> [mainClass] args...
Runs a jar file.
Use yarn jar to launch YARN applications instead.
Usage: hadoop key <subcommand> [options]
| COMMAND_OPTION | Description |
|---|---|
| create keyname [-cipher cipher] [-size size] [-description description] [-attr attribute=value] [-provider provider] [-strict] [-help] | Creates a new key for the name specified by the keyname argument within the provider specified by the -provider argument. The -strict flag will cause the command to fail if the provider uses a default password. You may specify a cipher with the -cipher argument. The default cipher is currently “AES/CTR/NoPadding”. The default keysize is 128. You may specify the requested key length using the -size argument. Arbitrary attribute=value style attributes may be specified using the -attr argument. -attr may be specified multiple times, once per attribute. |
| roll keyname [-provider provider] [-strict] [-help] | Creates a new version for the specified key within the provider indicated using the -provider argument. The -strict flag will cause the command to fail if the provider uses a default password. |
| delete keyname [-provider provider] [-strict] [-f] [-help] | Deletes all versions of the key specified by the keyname argument from within the provider specified by -provider. The -strict flag will cause the command to fail if the provider uses a default password. The command asks for user confirmation unless -f is specified. |
| list [-provider provider] [-strict] [-metadata] [-help] | Displays the keynames contained within a particular provider as configured in core-site.xml or specified with the -provider argument. The -strict flag will cause the command to fail if the provider uses a default password. -metadata displays the metadata. |
| -help | Prints usage of this command |
Manage keys via the KeyProvider. For details on KeyProviders, see the Transparent Encryption Guide.
Providers frequently require that a password or other secret is supplied. If the provider requires a password and is unable to find one, it will use a default password and emit a warning message that the default password is being used. If the -strict flag is supplied, the warning message becomes an error message and the command returns immediately with an error status.
NOTE: Some KeyProviders (e.g. org.apache.hadoop.crypto.key.JavaKeyStoreProvider) do not support uppercase key names.
NOTE: Some KeyProviders do not directly execute a key deletion (e.g. performs a soft-delete instead, or delay the actual deletion, to prevent mistake). In these cases, one may encounter errors when creating/deleting a key with the same name after deleting it. Please check the underlying KeyProvider for details.
View and modify Hadoop tracing settings. See the Tracing Guide.
Commands useful for administrators of a hadoop cluster.
Usage:
hadoop daemonlog -getlevel <host:port> <classname> [-protocol (http|https)] hadoop daemonlog -setlevel <host:port> <classname> <level> [-protocol (http|https)]
| COMMAND_OPTION | Description |
|---|---|
| -getlevel host:port classname [-protocol (http|https)] | Prints the log level of the log identified by a qualified classname, in the daemon running at host:port. The -protocol flag specifies the protocol for connection. |
| -setlevel host:port classname level [-protocol (http|https)] | Sets the log level of the log identified by a qualified classname, in the daemon running at host:port. The -protocol flag specifies the protocol for connection. |
Get/Set the log level for a Log identified by a qualified class name in the daemon dynamically. By default, the command sends a HTTP request, but this can be overridden by using argument -protocol https to send a HTTPS request.
Example:
$ bin/hadoop daemonlog -setlevel 127.0.0.1:50070 org.apache.hadoop.hdfs.server.namenode.NameNode DEBUG $ bin/hadoop daemonlog -getlevel 127.0.0.1:50470 org.apache.hadoop.hdfs.server.namenode.NameNode DEBUG -protocol https
Note that the setting is not permanent and will be reset when the daemon is restarted. This command works by sending a HTTP/HTTPS request to the daemon’s internal Jetty servlet, so it supports the following daemons:
However, the command does not support KMS server, because its web interface is based on Tomcat, which does not support the servlet.