_index.md 22 KB


title: "Administration" date: 2019-03-13T18:28:09-07:00 draft: false

weight: 4

Reference Architecture

A recommended setup consists in:

Monitoring

Performing a GET /desktop/debug/is_alive will return a 200 response if running.

Load Balancers

Hue is often run with:

Task Server

The task server is currently a work in progress to outsource all the blocking or resource intensive operations outside of the API server. Follow (HUE-8738)[https://issues.cloudera.org/browse/HUE-8738) for more information on when first usable task will be released.

Until then, here is how to try the task server service.

Make sure you have Rabbit MQ installed and running.

sudo apt-get install rabbitmq-server -y

In hue.ini, telling the API server that the Task Server is available:

[desktop]
[[task_server]]
enabled=true

Starting the Task server:

./build/env/bin/celery worker -l info -A desktop

Running a test tasks:

./build/env/bin/hue shell

from desktop.celery import debug_task

debug_task.delay()
debug_task.delay().get() # Works if result backend is setup and task_server is true in the hue.ini

Starting the Task Scheduler server:

./build/env/bin/celery -A core beat -l info

or when Django Celery Beat is enabled:

./build/env/bin/celery -A core beat -l info --scheduler django_celery_beat.schedulers:DatabaseScheduler

Proxy

A Web proxy lets you centralize all the access to a certain URL and prettify the address (e.g. ec2-54-247-321-151.compute-1.amazonaws.com --> demo.gethue.com).

Here is one way to do it with Apache.

Quick Start Wizard

The Quick Start wizard allows you to perform the following Hue setup operations by clicking the tab of each step or sequentially by clicking Next in each screen:

  1. Check Configuration validates your Hue configuration. It will note any potential misconfiguration and provide hints as to how to fix them. You can edit the configuration file described in the next section or use Cloudera Manager, if installed, to manage your changes.
  2. Examples contains links to install examples into the Hive, Impala, MapReduce, Spark, Oozie, Solr Dashboard and Pig Editor applications.
  3. Users contains a link to the User Admin application to create or import users and a checkbox to enable and disable collection of usage information.

Configuration

Displays a list of the installed Hue applications and their configuration. The location of the folder containing the Hue configuration files is shown at the top of the page. Hue configuration settings are in the hue.ini configuration file.

Click the tabs under Configuration Sections and Variables to see the settings configured for each application. For information on configuring these settings, see Hue Configuration in the Hue installation manual.

Hue ships with a default configuration that will work for pseudo-distributed clusters. If you are running on a real cluster, you must make a few changes to the hue.ini configuration file (/etc/hue/hue.ini when installed from the package version) or pseudo-distributed.ini in desktop/conf when in development mode). The following sections describe the key configuration options you must make to configure Hue.

To list all available configuration options, run: $ /usr/share/hue/build/env/bin/hue config_help | less This commands outlines the various sections and options in the configuration, and provides help and information on the default values.
To view the current configuration from within Hue, open: http:///hue/dump_config
Hue loads and merges all of the files with extension `.ini` located in the `/etc/hue` directory. Files that are alphabetically later take precedence.

Administration

Now that you've installed and started Hue, you can feel free to skip ahead to the <> section. Administrators may want to refer to this section for more details about managing and operating a Hue installation.

Configuration Validation

Hue can detect certain invalid configuration.

To view the configuration of a running Hue instance, navigate to http://myserver:8888/hue/dump_config, also accessible through the About application.

Server Logs

Displays the Hue Server log and allows you to download the log to your local system in a zip file.

Threads

Read more on the Threads and Metrics pages blog post

Threads page can be very helpful in debugging purposes. It includes a daemonic thread and the thread objects serving concurrent requests. The host name, thread name identifier and current stack frame of each are displayed. Those are useful when Hue “hangs”, sometimes in case of a request too CPU intensive. There is also a REST API to get the dump of Threads using 'desktop/debug/threads'

Metrics

Read more on the Threads and Metrics pages blog post

Hue uses the PyFormance Python library to collect the metrics. These metrics are represented as gauge, counters, meter, rate of events over time, histogram, statistical distribution of values. A REST API endpoint '/desktop/metrics/' to get all the metrics dump as json is also exposed

The below metrics of most concern to us are displayed on the page:

  • requests.active
  • requests.exceptions
  • requests.response-time
  • threads.daemon
  • threads.total
  • users
  • users.active

One of the most useful ones are the percentiles of response time of requests and the count of active users. Admins can either filter a particular property in all the metrics or select a particular metric for all properties

User management

The User Admin application lets a superuser add, delete, and manage Hue users and groups, and configure group permissions. Superusers can add users and groups individually, or import them from an LDAP directory. Group permissions define the Hue applications visible to group members when they log into Hue and the application features available to them.

Click the User Admin icon in the top right navigation bar under your username.

LDAP

LDAP or PAM pass-through authentication with Hive or Impala and Impersonation .

Users

The User Admin application provides two levels of user privileges: superusers and users.

  • Superusers — The first user who logs into Hue after its initial installation becomes the first superuser. Superusers have permissions to perform administrative functions:

    • Add and delete users
    • Add and delete groups
    • Assign permissions to groups
    • Change a user into a superuser
    • Import users and groups from an LDAP server
  • Users can change their name, e-mail address, and password and log in to Hue and run Hue applications, subject to the permissions provided by the Hue groups to which they belong.

Adding a User

  1. In the User Admin page, click Add User.
  2. In the Credentials screen, add required information about the user. Once you provide the required information you can click the wizard step tabs to set other information.

blank spaces are not allowed and the name cannot begin with a
number. The user name is used to log into Hue and in file
permissions and job submissions. This is a required field.

For non-superusers, the user and group of the directory are
username. For superusers, the user and group are username and
supergroup.</td></tr></table>
  1. Click Add User to save the information you specified and close the Add User wizard or click Next.
  2. In the Names and Groups screen, add optional information.
Username A user name that contains only letters, numbers, and underscores;
Password and Password confirmation A password for the user. This is a required field.
Create home directory Indicate whether to create a directory named /user/username in HDFS.
First name and Last name The user's first and last name.
E-mail addressThe user's e-mail address. The e-mail address is used by the Job Designer and Beeswax applications to send users an e-mail message after certain actions have occurred. The Job Designer sends an e-mail message after a job has completed. Beeswax sends a message after a query has completed. If an e-mail address is not specified, the application will not attempt to email the user.
Groups The groups to which the user belongs. By default, a user is assigned to the **default** group, which allows access to all applications. See [Permissions](#permissions).
  1. Click Add User to save the information you specified and close the Add User wizard or click Next.
  2. In the Advanced screen, add status information.
Active Indicate that the user is enabled and allowed to log in. Default: checked.
Superuser status Assign superuser privileges to the user.
  1. Click Add User to save the information you specified and close the Add User wizard.

Deleting a User

  1. Check the checkbox next to the user name and click Delete.
  2. Click Yes to confirm.

Editing a User

  1. Click the user you want to edit in the Hue Users list.
  2. Make the changes to the user and then click Update user.

Importing Users from an LDAP Directory

Note:

Importing users from an LDAP directory does not import any password information. You must add passwords manually in order for a user to log in.

To add a user from an external LDAP directory:

  1. Click Add/sync LDAP user.
  2. Specify the user properties:
UsernameThe user name.
Distinguished nameIndicate that Hue should use a full distinguished name for the user. This imports the user's first and last name, username, and email, but does not store the user password.
Create home directory Indicate that Hue should create a home directory for the user in HDFS.
  1. Click Add/sync user.

    If the user already exists in the User Admin, the user information in User Admin is synced with what is currently in the LDAP directory.

Syncing Users and Groups with an LDAP Directory

You can sync the Hue user database with the current state of the LDAP directory using the Sync LDAP users/groups function. This updates the user and group information for the already imported users and groups. It does not import any new users or groups.

  1. Click Sync LDAP users/groups.
  2. The Create Home Directories checkbox creates home directories in HDFS for existing imported members that don't have home directories.
  3. In the Sync LDAP users and groups dialog, click Sync to perform the sync.

Reset a password

Programmatically

When a Hue administrator loses their password, a more programmatic approach is required to secure the administrator again. Hue comes with a wrapper around the python interpreter called the “shell” command. It loads all the libraries required to work with Hue at a programmatic level. To start the Hue shell, type the following command from the Hue installation root.

Then:

cd /usr/lib/hue (or /opt/cloudera/parcels/CDH-XXXXX/share/hue if using parcels and CM)
build/env/bin/hue shell

The following is a small script, that can be executed within the Hue shell, to change the password for a user named “example”:

from django.contrib.auth.models import User
user = User.objects.get(username='example')
user.set_password('some password')
user.save()

The script can also be invoked in the shell by using input redirection (assuming the script is in a file named script.py):

build/env/bin/hue shell < script.py

How to make a certain user a Hue admin

build/env/bin/hue  shell

Then set these properties to true:

from django.contrib.auth.models import User

a = User.objects.get(username='hdfs')
a.is_staff = True
a.is_superuser = True
a.set_password('my_secret')
a.save()

** Via a command**

Go on the Hue machine, then in the Hue home directory and either type:

To change the password of the currently logged in Unix user:

build/env/bin/hue changepassword

If you don't remember the admin username, create a new Hue admin (you will then also be able to login and could change the password of another user in Hue):

build/env/bin/hue createsuperuser

Read more about it here.

Above works with the `AllowFirstUserBackend`, it might be different if another backend is used.

Groups

Superusers can add and delete groups, configure group permissions, and assign users to group memberships.

Adding a Group

You can add groups, and delete the groups you've added. You can also import groups from an LDAP directory.

  1. In the User Admin window, click Groups and then click Add Group.
  2. Specify the group properties:
Name The name of the group. Group names can only be letters, numbers, and underscores; blank spaces are not allowed.
MembersThe users in the group. Check user names or check Select all.
PermissionsThe applications the users in the group can access. Check application names or check Select all.
  1. Click Add group.

Adding Users to a Group

  1. In the User Admin window, click Groups.
  2. Click the group.
  3. To add users to the group, check the names in the list provided or check Select All.
  4. Click Update group.

Deleting a Group

  1. Click Groups.
  2. Check the checkbox next to the group and click Delete.
  3. Click Yes to confirm.

Limit users can login only if they are belong to one of listed LDAP groups

[desktop]
[[ldap]]
login_groups=ldap_grp1,ldap_grp2,ldap_grp3

Importing Groups from an LDAP Directory

  1. From the Groups tab, click Add/sync LDAP group.
  2. Specify the group properties:
Name The name of the group.
Distinguished name Indicate that Hue should use a full distinguished name for the group.
Import new members Indicate that Hue should import the members of the group.
Import new members from all subgroups Indicate that Hue should import the members of the subgroups.
Create home directories Indicate that Hue should create home directories in HDFS for the imported members.
  1. Click Add/sync group.

Permissions

Permissions for Hue applications are granted to groups, with users gaining permissions based on their group membership. Group permissions define the Hue applications visible to group members when they log into Hue and the application features available to them.

  1. Click Permissions.
  2. Click the application for which you want to assign permissions.
  3. Check the checkboxes next to the groups you want to have permission for the application. Check Select all to select all groups.
  4. Click Update permission. The new groups will appear in the Groups column in the Hue Permissions list.

Read more about it here.

Process Hierarchy

A script called supervisor manages all Hue processes. The supervisor is a watchdog process -- its only purpose is to spawn and monitor other processes. A standard Hue installation starts and monitors the following processes:

  • runcpserver - a web server based on CherryPy that provides the core web functionality of Hue

If you have installed other applications into your Hue instance, you may see other daemons running under the supervisor as well.

You can see the supervised processes running in the output of ps -f -u hue:

UID        PID  PPID  C STIME TTY          TIME CMD
hue       8685  8679  0 Aug05 ?        00:01:39 /usr/share/hue/build/env/bin/python /usr/share/hue/build/env/bin/desktop runcpserver

Note that the supervisor automatically restarts these processes if they fail for any reason. If the processes fail repeatedly within a short time, the supervisor itself shuts down.

Logging

The Hue logs are found in /var/log/hue, or in a logs directory under your Hue installation root. Inside the log directory you can find:

  • An access.log file, which contains a log for all requests against the Hue web server.
  • A supervisor.log file, which contains log information for the supervisor process.
  • A supervisor.out file, which contains the stdout and stderr for the supervisor process.
  • A .log file for each supervised process described above, which contains the logs for that process.
  • A .out file for each supervised process described above, which contains the stdout and stderr for that process.

If users on your cluster have problems running Hue, you can often find error messages in these log files. If you are unable to start Hue from the init script, the supervisor.log log file can often contain clues.

Viewing Recent Log Messages

In addition to logging INFO level messages to the logs directory, the Hue web server keeps a small buffer of log messages at all levels in memory. You can view these logs by visiting http://myserver:8888/hue/logs. The DEBUG level messages shown can sometimes be helpful in troubleshooting issues.

Troubleshooting

To troubleshoot why Hue is slow or consuming high memory, admin can enable instrumentation by setting the instrumentation flag to True.

[desktop]
instrumentation=true
If django_debug_mode is enabled, instrumentation is automatically enabled. This flag appends the response time and the total peak memory used since Hue started for every logged request.

Instrumentation enabled

[17/Apr/2018 15:18:43 -0700] access       INFO     127.0.0.1 admin - "POST /jobbrowser/jobs/ HTTP/1.1" `returned in 97ms (mem: 135mb)`

Instrumentation not enabled

[23/Apr/2018 10:59:01 -0700] INFO     127.0.0.1 admin - "POST /jobbrowser/jobs/ HTTP/1.1" returned in 88ms

Database

Hue requires a SQL database to store small amounts of data, including user account information as well as history of job submissions and Hive queries. By default, Hue is configured to use the embedded database SQLite for this purpose, and should require no configuration or management by the administrator. However, MySQL is the recommended database to use. This section contains instructions for configuring Hue to access MySQL and other databases.

Inspecting the Database

The default SQLite database used by Hue is located in: /usr/share/hue/desktop/desktop.db. You can inspect this database from the command line using the sqlite3 program or typing `/usr/share/hue/build/env/bin/hue dbshell'. For example:

sqlite3 /usr/share/hue/desktop/desktop.db
SQLite version 3.6.22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"
sqlite> select username from auth_user;
admin
test
sample
sqlite>

It is strongly recommended that you avoid making any modifications to the database directly using SQLite, though this trick can be useful for management or troubleshooting.

Backing up the Database

If you use the default SQLite database, then copy the desktop.db file to another node for backup. It is recommended that you back it up on a regular schedule, and also that you back it up before any upgrade to a new version of Hue.

Configuring to Access Another Database

Although SQLite is the default database type, some advanced users may prefer to have Hue access an alternate database type. Note that if you elect to configure Hue to use an external database, upgrades may require more manual steps in the future.

The following instructions are for MySQL, though you can also configure Hue to work with other common databases such as PostgreSQL and Oracle.

Note that Hue has only been tested with SQLite and MySQL database backends.

Configuring to Store Data in MySQL

To configure Hue to store data in MySQL:

  1. Create a new database in MySQL and grant privileges to a Hue user to manage this database.

    mysql> create database hue;
    Query OK, 1 row affected (0.01 sec)
    mysql> grant all on hue.* to 'hue'@'localhost' identified by 'secretpassword';
    Query OK, 0 rows affected (0.00 sec)
    
  2. Shut down Hue if it is running.

  3. To migrate your existing data to MySQL, use the following command to dump the existing database data to a text file. Note that using the ".json" extension is required.

    /usr/share/hue/build/env/bin/hue dumpdata > $some-temporary-file.json
    
  4. Open the hue.ini file in a text editor. Directly below the [[database]] line, add the following options (and modify accordingly for your MySQL setup):

    host=localhost
    port=3306
    engine=mysql
    user=hue
    password=secretpassword
    name=hue
    
  5. As the Hue user, configure Hue to load the existing data and create the necessary database tables:

    /usr/share/hue/build/env/bin/hue syncdb --noinput
    mysql -uhue -psecretpassword -e "DELETE FROM hue.django_content_type;"
    /usr/share/hue/build/env/bin/hue loaddata $temporary-file-containing-dumped-data.json
    

Your system is now configured and you can start the Hue server as normal.