Adding and Editing Metadata

Minimum Required Role: Metadata Administrator (also provided by Full Administrator)

Cloudera Navigator supports adding metadata to extracted entities. You can add and edit two types of metadata:
  • Custom metadata - Display name, description, tags, and key-value pairs. You can add and edit custom metadata using the Navigator UI, MapReduce service and job properties, HDFS metadata files, and the Cloudera Navigator Data Management API.
  • Managed metadata. You can add and edit managed metadata using the Navigator UI and the API.

Adding and Editing Metadata Using the Navigator UI

  1. Run a search in the Navigator UI.
  2. Click an entity link returned in the search. The Details tab displays.
  3. To the left of the Details tab, click Actions > Edit Metadata.... The Edit Metadata dialog box drops down.
  4. Add metadata fields:
    • In the Name field, type a new display name.
    • In the Description field, type a description.
    • In the Tags field, type a tag and press Enter or Tab to create new tag entries.
    • Managed Metadata
      1. Click the and select a property.
      2. Click the value field after the : to display type-specific selection controls such as integer spinners and date selection controls. Either type the value or use the controls to select a value.
      Click to add another managed property key-value pair or another value for a given key.
    • Key-Value Pairs
      1. Click to add a key-value pair.
      2. Type a key and a value. You can specify special characters (for example, ".", " ") in the name, but it makes searching for the entity more difficult because some characters collide with special characters in the search syntax.
  5. Click Save. The new metadata appears in the Managed Metadata or Custom Metadata pane.

Custom Metadata Example

In the following figure, the tag northeast and the property year with value 2016 have been added to the file customers:

After you save, the metadata appears in the Custom Metadata pane:

Managed Metadata Example

In the following figure, managed properties are being configured for the years entity. The managed property emailFrom has been configured with a value, and the managed property emailTo is having a second value configured:

If a provided value does not satisfy the constraints specified in the property definition—in this case, a regular expression that describes email addresses—a message displays when you try to save the value:

After you correctly specify the second value and save, the properties display in the Managed Metadata pane:

Editing MapReduce Custom Metadata

You can associate custom metadata with arbitrary configuration parameters to MapReduce jobs and job executions. The configuration parameters to be extracted by Navigator can be specified statically or dynamically.

To specify configuration parameters statically for all MapReduce jobs and job executions, do the following:
  1. Do one of the following:
    • Select Clusters > Cloudera Management Service > Cloudera Management Service.
    • On the Home > Status tab, in Cloudera Management Service table, click the Cloudera Management Service link.
  2. Click the Configuration tab.
  3. Select Scope > Navigator Metadata Server.
  4. Select Category > Advanced.
  5. Click Navigator Metadata Server Advanced Configuration Snippet for cloudera-navigator.properties.
  6. Specify values for the following properties:
    • nav.user_defined_properties - A comma-separated list of user-defined property names.
    • nav.tags - A comma-separated list of property names that serve as tags. The property nav.tags can point to multiple property names that serve as tags, but each of those property names can only specify a single tag.
  7. Click Save Changes to commit the changes.
  8. Click the Instances tab.
  9. Restart the role.
  10. In the MapReduce job configuration, set the value of the property names you specified in step 6.
To specify configuration parameters dynamically:
  1. Specify one or more of the following properties in a job configuration:
    • Job properties (type:OPERATION)
      • nav.job.user_defined_properties - A comma-separated list of user-defined property names
      • nav.job.tags - A comma-separated list of property names that serve as tags
    • Job execution properties (type:OPERATION_EXECUTION)
      • nav.jobexec.user_defined_properties - A comma-separated list of user-defined property names
      • nav.jobexec.tags - A comma-separated list of property names that serve as tags
    The properties nav.job.tags and nav.jobexec.tags can point to multiple property names that serve as tags, but each of those property names can only specify a single tag.
  2. In the MapReduce job configuration, set the value of the property names you specified in step 1.

Example: Setting Properties Dynamically

Add the tags onetag and twotag to a job:
  1. Dynamically add the job_tag1 and job_tag2 properties:
    conf.set("nav.job.tags", "job_tag1, job_tag2");
  2. Set the job_tag1 property to onetag:
    conf.set("job_tag1", "onetag");
  3. Set the job_tag2 property to twotag:
    conf.set("job_tag2", "twotag");
Add the tag atag to a job execution:
  1. Dynamically add the job_tag property:
    conf.set("nav.jobexec.tags","job_exec_tag");
  2. Set the job_exec_tag property to atag:
    conf.set("job_exec_tag", "atag"); 
Add the user-defined key key with the value value:
  1. Dynamically add the user-defined key bar:
    conf.set("nav.job.user_defined_properties", "key");
  2. Set the value of the user-defined key key to value:
    conf.set("key", "value")

Editing HDFS Custom Metadata Using Metadata Files

You can add tags and properties to HDFS entities using metadata files. With metadata files, you can assign metadata to entities in bulk and create metadata before it is extracted. A metadata file is a JSON file with the following structure:

{
  "name" : "aName",
  "description" : "a description",
  "properties" : {
    "prop1" : "value1", "prop2" : "value2"
  },
  "tags" : [ "tag1" ]
}
To add metadata files to files and directories, create a metadata file with the extension .navigator, naming the files as follows:
  • File - The path of the metadata file must be .filename.navigator. For example, to apply properties to the file /user/test/file1.txt, the metadata file path is /user/test/.file1.txt.navigator.
  • Directory - The path of the metadata file must be dirpath/.navigator. For example, to apply properties to the directory /user, the metadata path must be /user/.navigator.
The metadata file is applied to the entity metadata when the extractor runs.

Editing HDFS and Hive Metadata Using the Navigator Metadata API

You can use the Cloudera Navigator Data Management API to modify the custom metadata of HDFS or Hive entities, whether the entities have been extracted or not. If an entity has been extracted when the API is called, the metadata is applied immediately. If the entity has not been extracted, you can preregister metadata, which is then applied once the entity is extracted. Metadata is saved regardless of whether or not a matching entity is extracted, and Navigator does not perform any cleanup of unused metadata.

If you call the API before the entity is extracted, the custom metadata is stored with the entity's:
  • Identity
  • Source ID
  • Metadata fields (name, description, tags, properties)
  • Fields relevant to the identifier
The rest of the entity fields (such as type) are not present. To view all stored metadata, use the API to search for entities without an internal type:
curl http://Navigator_Metadata_Server_host:port/api/v9/entities/?query=-internalType:* -u username:password -X GET 

Custom metadata provided through the API overwrites existing metadata. For example, if you call the API with an empty name and description, empty array for tags, and empty dictionary for properties, the call removes this metadata. If you omit the tags or properties fields, the existing values remain unchanged.

Modifying custom metadata using HDFS metadata files and the metadata API at the same time is not supported. You must use one or the other, because the two methods work differently. Metadata specified in files is merged with existing metadata, whereas the API overwrites metadata. Also, the updates provided by metadata files wait in a queue before being merged, but API changes are committed immediately. Some inconsistency can occur if a metadata file is merged when the API is in use.

You modify metadata using either the PUT or POST method. Use the PUT method if the entity has been extracted, and the POST method to preregister metadata. Use the following syntax:
  • PUT
    curl http://Navigator_Metadata_Server_host:port/api/v9/entities/identity -u username:password -X PUT -H\
    "Content-Type: application/json" -d '{properties}'
    where identity is an entity ID and properties are:
    • name - Name metadata.
    • description - Description metadata.
    • tags - Tag metadata.
    • properties - Custom metadata properties. The format is {key: value}.
    • customProperties - Managed metadata properties. The format is {namespace: {key: value}}. If a property is assigned a value that does not conform to type constraints, an error is returned.
    All existing naming rules apply, and if any value is invalid, the entire request is denied.
  • POST
    curl http://Navigator_Metadata_Server_host:port/api/v9/entities/ -u username:password -X POST -H\
    "Content-Type: application/json" -d '{properties}'
    where properties are:
    • sourceId (required) - An existing source ID. After the first extraction, you can retrieve source IDs using the call:
      curl http://Navigator_Metadata_Server_host:port/api/v9/entities/?query=type:SOURCE -u username:password -X GET
      For example:
      [ ...
      {  {
      "identity": "61cfefd303d4284b7f5014b701f2c76d",
      "originalName": "source.listing",
      "originalDescription": null,
      "sourceId": "012437f9eeb3c23dc69e679ac94a7fa2",
      "firstClassParentId": null,
      "parentPath": "/user/hdfs/.cm/distcp/2016-02-03_487",
      ...
      "properties": {
      "__cloudera_internal__hueLink":
      "http://vc0142.halxg.cloudera.com:8888/filebrowser/#/user/hdfs/.cm/distcp/2016-02-03_487/source.listing"
       },
      "technicalProperties": null,
      "fileSystemPath": "/user/hdfs/.cm/distcp/2016-02-03_487/source.listing",
      "type": "FILE",
      "size": 92682,
      "created": "2016-02-03T21:12:16.587Z",
      "lastModified": "2016-02-03T21:12:16.587Z",
      "lastAccessed": "2016-02-03T21:12:16.587Z",
      "permissions": "rw-r--r--",
      "owner": "hdfs",
      "group": "supergroup",
      "blockSize": 134217728,
      "mimeType": "application/octet-stream",
      "replication": 3,
      "userEntity": false,
      "deleted": false,
      "sourceType": "HDFS",
      "metaClassName": "fselement",
      "packageName": "nav",
      "internalType": "fselement"
      }, ...
      If you have multiple services of a given type, you must specify the source ID that contains the entity you expect it to match.
    • parentPath - The path of the parent entity, defined as:
      • HDFS file or directory - fileSystemPath of the parent directory. (Do not provide this field if the entity affected is the root directory.) Example parentPath for /user/admin/input_dir: /user/admin. If you add metadata to a directory, the metadata does not propagate to any files or folders in that directory.
      • Hive database - If you are updating database metadata, do not specify this field.
      • Hive table or view - The name of database containing the table or view. Example for a table in the default database: default.
      • Hive column - database name/table name/view name. Example for a column in the sample_07 table: default/sample_07.
    • originalName (required) - The name as defined by the source system.
      • HDFS file or directory- Name of file or directory (ROOT if the entity is the root directory). Example originalName for /user/admin/input_dir: input_dir.
      • Hive database, table, view, or column - The name of the database, table, view, or column.
        • Example for default database: default
        • Example for sample_07 table: sample_07
    • name - Name metadata.
    • description - Description metadata.
    • tags - Tag metadata.
    • properties - Custom metadata properties. The format is {key: value}.
    All existing naming rules apply, and if any value is invalid, the entire request is denied.

HDFS PUT Custom Metadata Example for /user/admin/input_dir Directory

curl http://Navigator_Metadata_Server_host:port/api/v9/entities/e461de8de38511a3ac6740dd7d51b8d0 -u username:password -X PUT -H "Content-Type: application/json"\
-d '{"name":"my_name","description":"My description", "tags":["tag1","tag2"],"properties":{"property1":"value1","property2":"value2"}}'

HDFS POST Custom Metadata Example for /user/admin/input_dir Directory

curl http://Navigator_Metadata_Server_host:port/api/v9/entities/ -u username:password -X POST -H "Content-Type: application/json"\
-d '{"sourceId":"a09b0233cc58ff7d601eaa68673a20c6", "parentPath":"/user/admin","originalName":"input_dir", "name":"my_name","description":"My description",\
"tags":["tag1","tag2"],"properties":{"property1":"value1","property2":"value2"}}'

Hive POST Custom Metadata Example for total_emp Column

curl http://Navigator_Metadata_Server_host:port/api/v9/entities/ -u username:password -X POST -H "Content-Type: application/json"\
-d '{"sourceId":"4fbdadc6899638782fc8cb626176dc7b", "parentPath":"default/sample_07","originalName":"total_emp",\
"name":"my_name","description":"My description", "tags":["tag1","tag2"],"properties":{"property1":"value1","property2":"value2"}}'

HDFS PUT Managed Metadata Example

The following example demonstrates how to set two properties in the MailAnnotation namespace: a multivalued property emailTo and a single-valued property emailFrom:
curl http://Navigator_Metadata_Server_host:port/api/v9/entities/87afcb92d5de856c7e8292e2e12cf1ea -u admin:admin -X PUT -H "Content-Type: application/json"
-d '{"customProperties":{"MailAnnotation":{"emailTo":["lee@example.com","dana@example.com"],"emailFrom":"terry@email.com"}}}'
The response is:
{
  "identity" : "87afcb92d5de856c7e8292e2e12cf1ea",
  "originalName" : "years",
  "originalDescription" : null,
  "sourceId" : "012437f9eeb3c23dc69e679ac94a7fa2",
  "firstClassParentId" : null,
  "parentPath" : "/user/admin",
  "extractorRunId" : "012437f9eeb3c23dc69e679ac94a7fa2##1",
  "customProperties" : {
    "MailAnnotation" : {
      "emailTo" : [ "lee@example.com", "dana@example.com" ],
      "emailFrom" : "terry@email.com"
    }
  },
  "name" : null,
  "description" : null,
  "tags" : null,
  "properties" : {
    "__cloudera_internal__hueLink" : "Hue_Server_host:8888/filebrowser/#/user/admin/years"
  },
  "technicalProperties" : null,
  "fileSystemPath" : "/user/admin/years",
  "type" : "DIRECTORY",
  "size" : null,
  "created" : "2016-03-22T17:55:31.902Z",
  "lastModified" : "2016-03-22T17:59:14.065Z",
  "lastAccessed" : null,
  "permissions" : "rwxr-xr-x",
  "owner" : "hdfs",
  "group" : "admin",
  "blockSize" : null,
  "mimeType" : null,
  "replication" : null,
  "sourceType" : "HDFS",
  "metaClassName" : "fselement",
  "userEntity" : false,
  "deleted" : false,
  "packageName" : "nav",
  "internalType" : "fselement"
}

Accessing and Editing Metadata with the Navigator SDK

In addition to the metadata features provided by the Cloudera Navigator data management component UI, you can also access and edit metadata using the Navigator SDK. For information on the SDK, see the Navigator SDK documentation.