Hue Tarball Installation Guide
==============================
== Introduction
Hue is a graphical user interface to operate and develop applications for
Hadoop. Hue applications are collected into a desktop-style environment and
delivered as a Web application, requiring no additional installation for
individual users.
This guide describes how to install and configure a Hue tarball. For
information about installing Hue packages, see
https://wiki.cloudera.com/display/DOC/Installing+Hue[Installing Hue].
There is also a companion SDK guide that describes how to develop
new Hue applications:
http://archive.cloudera.com/cdh3/hue/sdk/sdk.html[Hue SDK Documentation]
IMPORTANT: Hue requires the Cloudera Distribution for Hadoop (CDH), version 2 or 3.
.Conventions Used in this Guide:
* Commands that must be run with +root+ permission have a +#+ command prompt.
* Commands that do not require +root+ permission have a +$+ command prompt.
== Installation Instructions
The following instructions describe how to install the Hue tarball on a
multi-node cluster. You must install CDH2 or CDH3 first and update some
Hadoop configuration files before installing Hue.
IMPORTANT: You'll need to install the Hue Plug-ins
on _every_ machine that's running Hadoop daemons.
=== Install CDH2 or CDH3
To use Hue, you must be running the Cloudera Distribution for Hadoop
with a version number of at least `0.20.1+133`. If you are not running this
version of CDH or later, upgrade your cluster before proceeding.
=== Install Hue
Hue consists of a web service that runs on a special node in your cluster.
Choose one node where you want to run Hue. This guide refers to that node as
the _Hue Server_. For optimal performance, this should be one of the nodes
within your cluster, though it can be a remote node as long as there are no
overly restrictive firewalls. For small clusters of less than 10 nodes,
you can use your existing master node as the Hue Server.
You can download the Hue tarball here:
http://github.com/downloads/cloudera/hue/hue-latest.tgz[tarball].
==== Hue Dependencies
Hue employs some Python modules which use native code and requires
certain development libraries be installed on your system. To install from the
tarball, you must have the following installed:
.Required Dependencies
[grid="rows"]
``~
Redhat,Debian
~~~~~~~~~~
gcc,gcc
libxml2-devel,libxml2-dev
libxslt-devel,libxslt-dev
mysql-devel,librarysqlclient-dev
python-devel,python-dev
python-setuptools,python-setuptools
sqlite-devel,libsqlite3-dev
~~~~~~~~~~
==== Build
Configure `$HADOOP_HOME` and `$PREFIX` with the path of your Hadoop
installation and the path where you want to install Hue by running:
----
$ HADOOP_HOME=/path/to/hadoop-0.20 PREFIX=/path/to/install/into make install
----
You can install Hue anywhere on your system - it does not need root permission
although additional thirdparty SDK applications may.
It is a good practice to create a new user for Hue and either install Hue in
that user's home directory, or in a directory within `/usr/local`.
==== Install Hadoop Plugins
In order to communicate with Hadoop, Hue requires a plug-in jar that you must
install and configure. This jar is: `desktop/libs/hadoop/java-lib/hue-plugins-0.9.jar`,
relative to the Hue installation directory.
Run these commands to create a symlink your Hadoop lib directory
(`/usr/lib/hadoop-0.20/lib` if you installed CDH via a Debian or RPM package)
to this jar:
----
$ cd /usr/lib/hadoop/lib
$ ln -s /usr/share/hue/desktop/libs/hadoop/java-lib/hue*jar .
# Restart Hadoop
----
NOTE: On a multi-node cluster, you must install the plug-in jar on every
node. You do not need to install all of the Hue components on every node.
==== Restart Hadoop
After making the changes in your Hadoop configuration, restart the Hadoop daemons:
----
# /etc/init.d/hadoop-0.20-datanode restart
# /etc/init.d/hadoop-0.20-namenode restart
# /etc/init.d/hadoop-0.20-jobtracker restart
# /etc/init.d/hadoop-0.20-secondarynamenode restart
# /etc/init.d/hadoop-0.20-tasktracker restart
----
==== Starting Hue
To start Hue, use `build/env/bin/supervisor`. This will start
several subprocesses, corresponding to the different Hue components.
==== Troubleshooting the Hue Tarball Installation
.Q: I moved my Hue installation from one directory to another and now Hue no longer functions correctly.
A: Due to the use of absolute paths by some Python packages, you must run a series of commands if you move your Hue installation. In the new location, run:
----
$ rm app.reg
$ rm -r build
$ make apps
----
.Q: Why does "make install" compile other pieces of software?
A: In order to ensure that Hue is stable on a variety of distributions and architectures, it installs a Python virtual environment which includes its dependencies. This ensures that the software can depend on specific versions of various Python libraries and you don't have to be concerned about missing software components.
=== Configuring Hadoop for Hue
Hue requires that you install and configure some plugins in your
Hadoop installation. In order to enable the plugins, you must make some
small additions to your configuration files. Make these configuration changes
on each node in your cluster by editing the following files
in: `/etc/hadoop-0.20/conf/`
==== `hdfs-site.xml`
Add the following configuration properties to `hdfs-site.xml`:
----
dfs.namenode.plugins
org.apache.hadoop.thriftfs.NamenodePlugin
Comma-separated list of namenode plug-ins to be activated.
dfs.datanode.plugins
org.apache.hadoop.thriftfs.DatanodePlugin
Comma-separated list of datanode plug-ins to be activated.
dfs.thrift.address
0.0.0.0:9090
-----
==== `mapred-site.xml`
Add the following configuration properties to mapred-site.xml:
----
jobtracker.thrift.address
0.0.0.0:9290
mapred.jobtracker.plugins
org.apache.hadoop.thriftfs.ThriftJobTrackerPlugin
Comma-separated list of jobtracker plug-ins to be activated.
----
==== `hadoop-metrics.properties`
To enable full monitoring in the Health application, the metrics
contexts must not be NullContext. You can configure `hadoop-metrics.properties` as shown below:
----
# Exposes /metrics URL endpoint for metrics information.
dfs.class=org.apache.hadoop.metrics.spi.NoEmitMetricsContext
mapred.class=org.apache.hadoop.metrics.spi.NoEmitMetricsContext
jvm.class=org.apache.hadoop.metrics.spi.NoEmitMetricsContext
rpc.class=org.apache.hadoop.metrics.spi.NoEmitMetricsContext
----
=== Further Hadoop Configuration and Caveats
==== `HADOOP_CLASSPATH` Caveat
If you are setting `$HADOOP_CLASSPATH` in your `hadoop-env.sh`, be sure
to set it in such a way that user-specified options are preserved. For example,
Correct:
----
# HADOOP_CLASSPATH=:$HADOOP_CLASSPATH
----
Incorrect:
----
# HADOOP_CLASSPATH=
----
This enables certain components of Hue to add to
Hadoop's classpath using the environment variable.
==== `hadoop.tmp.dir`
If your users are likely to be submitting jobs both using Hue
and from the same machine via the command line interface, they will be doing so as the `hue`
user if they're using Hue and via their own user account
on the command line. This leads to some contention
on the directory specified by `hadoop.tmp.dir`, which defaults
to `/tmp/hadoop-${user.name}`.
Specifically, `hadoop.tmp.dir` is used to unpack jars in `bin/hadoop jar`.
One work around to this is
to set `hadoop.tmp.dir` to `/tmp/hadoop-${user.name}-${hue.suffix}` in the core-site.xml file:
----
hadoop.tmp.dir
/tmp/hadoop-${user.name}${hue.suffix}
----
Unfortunately, when the variable is unset, you'll end up
with directories named `/tmp/hadoop-user_name-${hue.suffix}` in
`/tmp`. The job submission daemon, however, will still work.
=== Restart Your Hadoop Cluster
Restart all of the daemons in your cluster so that the plugins can be loaded.
You can confirm that the plugins are running correctly by tailing the daemon logs:
----
$ tail --lines=500 /var/log/hadoop-0.20/hadoop*namenode*.log | grep ThriftPlugin
2009-09-28 16:30:44,337 INFO org.apache.hadoop.thriftfs.ThriftPluginServer: Starting Thrift server
2009-09-28 16:30:44,419 INFO org.apache.hadoop.thriftfs.ThriftPluginServer:
Thrift server listening on 0.0.0.0:9090
----
[TIP]
.Configuring Your Firewall for Hue
============================================================
Hue currently requires that the machines within your cluster can connect to each other freely over TCP. The machines outside your cluster must be able to open TCP port 8088 on the Hue Server to interact with the system.
============================================================
== Configuring Hue
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 `/etc/hue/hue.ini` configuration file. The
following sections describe the key configuration options you must make to configure Hue.
[TIP]
.Listing all Configuration Options
============================================================
To list all available configuration options, run:
----
/usr/share/hue/build/env/bin/desktop config_help | less
----
This commands outlines the various sections and options in the configuration,
and provides help and information on the default values.
============================================================
[TIP]
.Viewing Current Configuration Options
============================================================
To view the current configuration from within Hue, open:
----
http:///dump_config
----
============================================================
[TIP]
.Using Multiple Files to Store Your Configuration
============================================================
Hue loads and merges all of the files with extension `.ini`
located in the `/etc/hue/conf/` directory. Files that are alphabetically later
take precedence.
============================================================
=== Web Server Configuration
Hue uses the CherryPy web server. You can use the following options to
change the IP address and port that the web server listens on. The default
setting is port 8088 on all configured IP addresses.
----
# Webserver listens on this address and port
http_host=0.0.0.0
http_port=8088
----
=== Authentication
By default, the first user who logs in to Hue can choose any
username and password and becomes an administrator automatically. This
user can create other user and administrator accounts. User information is
stored in the Django database in the Django backend.
The authentication system is pluggable. For more information, see the
http://archive.cloudera.com/cdh3/hue/sdk/sdk.html[Hue SDK Documentation].
=== Configuring Hue for SSL
You can configure Hue to serve over HTTPS. To do so, you must install
"pyOpenSSL" within Hue's context and configure your keys.
To install `pyOpenSSL`, from the root of your Hue installation path,
do the following steps:
1. Run this command:
----
$ ./build/env/bin/easy_install pyOpenSSL
----
2. Configure Hue to use your private key by adding the following
options to the `/etc/hue/hue.ini` configuration file:
----
ssl_certificate=/path/to/certificate
ssl_private_key=/path/to/key
----
3. Ideally, you would have an appropriate key signed by a Certificate Authority.
If you're just testing, you can create a self-signed key using the `openssl`
command that may be installed on your system:
----
# Create a key
$ openssl genrsa 1024 > host.key
# Create a self-signed certificate
$ openssl req -new -x509 -nodes -sha1 -key host.key > host.cert
----
[NOTE]
.Self-signed Certificates and File Uploads
============================================================
To upload files using the Hue File Browser over HTTPS requires
using a proper SSL Certificate. Self-signed certificates don't
work.
============================================================
=== Pointing Hue to Your Master Nodes
If your Hadoop cluster contains multiple nodes, you should configure
Hue to point to the external hostnames of your NameNode and
JobTracker. To do so, change the `namenode_host` and `jobtracker_host`
lines in the `/etc/hue/hue.ini` configuration file. Refer to the inline comments in the configuration file for more information.
== Starting Hue from the Tarball
After your cluster is running with the plugins enabled, you can start Hue on your Hue Server by running:
----
# build/env/bin/supervisor
----
Your Hue installation is now running.
== Administering Hue
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.
=== Hue Processes
==== 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
* `jobsubd` - a daemon which handles submission of jobs to Hadoop
* `beeswax server` - a daemon that manages concurrent Hive queries
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`:
------------------
[todd@monster01 ~]$ ps -f -u hue
UID PID PPID C STIME TTY TIME CMD
hue 7899 1 0 12:14 ? 00:00:00 /usr/share/hue/build/build/env/bin/python2.4 \
/usr/share/hue/desktop/build/env/bin/supervisor -p /var/run/hue/desktop/s
hue 7903 7899 1 12:14 ? 00:02:59 /usr/share/hue/desktop/build/env/bin/python2.4 \
/usr/share/hue/desktop/build/env/bin/desktop runcpserver
hue 7906 7899 0 12:14 ? 00:00:00 /usr/share/hue/desktop/build/env/bin/python2.4 \
/usr/share/hue/desktop/build/env/bin/desktop jobsubd
hue 7907 7899 0 12:14 ? 00:00:12 /usr/share/hue/desktop/build/env/bin/python2.4 \
/usr/share/hue/desktop/build/env/bin/desktop run_healthd
------------------
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.
=== Hue Logging
The Hue logs are found in `/logs`. Inside the log directory you can find:
* An `access.log`, which contains a log for all requests against the Hue web server.
* A `.log` file, which contains the logs for each of the processes described above.
* A `.out` file, which contains the stdout and stderr for each of the processes described above.
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 through your Web Browser
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:8088/logs`.
The `DEBUG` level messages shown can sometimes be helpful in troubleshooting issues.
=== The Hue 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 Hue 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. For example:
---------
# sqlite3 /usr/share/hue/desktop/desktop.db
SQLite version 3.3.6
Enter ".help" for instructions
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 Hue 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 Hue 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 may to work with other common databases such as PostgreSQL and Oracle.
But note that Hue has only been tested with SQLite and MySQL database backends.
===== Configuring Hue 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 to a text file.
----
$ /usr/share/hue/build/env/bin/desktop dumpdata
----
4. Open the `/etc/hue/hue.ini` file in a text editor. Directly below the `[desktop]` line, add the following options (and modify accordingly for your MySQL setup):
----
[[database]]
host=localhost
port=3306
engine=mysql
user=hue
password=secretpassword
name=hue
----
5. Install the Python drivers for MySQL into Hue's environment:
----
# su - hue -s /bin/bash
$ /usr/share/hue/build/env/bin/easy_install MySQL-python
----
`easy_install` will access the Internet to find MySQL-python.
If you don't have network access, you may specify a path
to a tarball (such as `/tmp/MySQL-python-1.2.2.tar.gz`) instead.
6. As the Hue user, configure Hue to load the existing data and create the
necessary database tables:
----
$ /usr/share/hue/build/env/bin/desktop loaddata
$ /usr/share/hue/build/env/bin/desktop syncdb --noinput
$ /usr/share/hue/build/env/bin/desktop migrate
----
Your system is now configured and you can start the Hue server as normal.
== Hue Applications
This section includes documentation specific to built-in Hue applications.
=== Beeswax, the Hive UI
==== Introduction
Beeswax is an application that is a component within Hue and helps you use Hive to query your data.
==== Installation
Beeswax is installed as part of Hue.
==== Hive Configuration
Beeswax, the Hive interface in Hue, includes Hive 0.5. You do
not need an existing Hive installation.
Your Hive data is stored in HDFS, normally under `/user/hive/warehouse`
(or any path you specify as `hive.metastore.warehouse.dir` in your
`hive-site.xml`). Make sure this location exists and is writable by
the users whom you expect to be creating tables. `/tmp` (on the local file
system) must be world-writable, as Hive makes extensive use of it.
==== Configuration
===== No Existing Hive Installation
Familiarize yourself with the configuration options in
`hive-site.xml` (see
http://wiki.apache.org/hadoop/Hive/AdminManual/Configuration).
Having a `hive-site.xml` is optional but often useful, particularly on setting
up a http://wiki.apache.org/hadoop/Hive/AdminManual/MetastoreAdmin[metastore].
You may store the `hive-site.xml` in `/etc/hue/conf`, or instruct
Beeswax to locate it using the `hive_conf_dir` configuration variable. See
`/etc/hue/conf/hue-beeswax.ini`.
===== Existing Hive Installation
In `/etc/hue/conf/hue-beeswax.ini`, modify `hive_conf_dir` to point to the directory containing `hive-site.xml`.
[[usage]]
== Using Hue
After installation, you can use Hue by navigating to `http://myserver:8088/`.
The following login screen appears:
image:images/login.png[]
Launch applications on the bottom-right.
image:images/open-apps.png[,width=50%]
The Help application guides users through the various installed applications.
=== Supported Browsers
Hue is primarily tested on Firefox 3.5 and Firefox 3.6, on Windows, Mac, and Linux.
Google Chrome and Safari work as well.
=== Feedback
Hue is currently at version 0.9. Your feedback is welcome.
The best way to send feedback is to join the
https://groups.google.com/a/cloudera.org/group/hue-user[mailing list], and send e-mail,
to mailto:hue-user@cloudera.org[hue-user@cloudera.org].
=== Reporting Bugs
If you find that something doesn't work, it'll often be helpful to include logs
from your server. These are available at the +/logs+ URL on Hue's web server
(not part of the graphical Hue UI). Please download the logs as a zip (or cut
and paste the ones that look relevant) and send those with your bug reports.
image:images/logs.png[]