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[]