# Installation
The following instructions describe how to install the Hue tarball on a
multi-node cluster. You need to also install Hadoop and its satellite components
(Oozie, Hive...) and update some Hadoop configuration files before running 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:
[https://github.com/cloudera/hue/releases](https://github.com/cloudera/hue/releases)
## 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
The full list is here: [https://github.com/cloudera/hue#prerequisites](https://github.com/cloudera/hue#prerequisites)
## Build
Configure `$PREFIX` with the path where you want to install Hue by running:
PREFIX=/usr/share make install
cd /usr/share/hue
You can install Hue anywhere on your system, and run Hue as a non-root user.
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/share`.
## Docker
Alternatively to building Hue, a [http://gethue.com/getting-started-with-hue-in-2-minutes-with-docker/](Hue Docker image) is available.
## Troubleshooting the 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.
## Starting the server
After your cluster is running with the plugins enabled, you can start Hue on
your Hue Server by running:
build/env/bin/supervisor
This will start several subprocesses, corresponding to the different Hue
components. Your Hue installation is now running.
# Configuration
## Reference Architecture
* 3 Hues and 1 Load Balancer
* Databases: MySQL InnoDB, PostgreSQL, Oracle
* LDAP
* Monitoring
* Impala HA
* HiveServer2 HA
* Downloads
[Read more about it here](http://gethue.com/performance-tuning/).
### Load Balancers
Hue is often run with:
* Cherrypy with Httpd
* [Apache mod Python](http://gethue.com/how-to-run-hue-with-the-apache-server/)
* [NGINX](Using NGINX to speed up Hue)
### 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](http://gethue.com/i-put-a-proxy-on-hue/).
## 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.
4. **Go!** - displays the Hue home screen, which contains links to the
different categories of applications supported by Hue: Query,
Hadoop, and Workflow.
## 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.
### Web Server Configuration
These configuration variables are under the `[desktop]` section in
the `hue.ini` configuration file.
### Specifying the HTTP port
Hue uses 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 8888 on all configured IP addresses.
# Webserver listens on this address and port
http_host=0.0.0.0
http_port=8888
### Specifying the Secret Key
For security, you should also specify the secret key that is used for secure
hashing in the session store. Enter a long series of random characters
(30 to 60 characters is recommended).
secret_key=jFE93j;2[290-eiw.KEiwN2s3['d;/.q[eIW^y#e=+Iei*@Mn
[desktop]
# Comma separated list of apps to not load at server startup.
app_blacklist=beeswax,impala,security,filebrowser,jobbrowser,rdbms,jobsub,pig,hbase,sqoop,zookeeper,metastore,spark,oozie,indexer
[Read more about it here](http://gethue.com/mini-how-to-disabling-some-apps-from-showing-up/).
### 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
[Hue SDK Documentation](sdk/sdk.html).
List of some of the possible authentications:
#### Username / Password
#### LDAP
#### SAML
[Read more about it](http://gethue.com/updated-saml-2-0-support/).
#### OpenId Connect
#### Multiple Authentication Backends
For example, to enable Hue to first attempt LDAP directory lookup before falling back to the database-backed user model, we can update the hue.ini configuration file or Hue safety valve in Cloudera Manager with a list containing first the LdapBackend followed by either the ModelBackend or custom AllowFirstUserDjangoBackend (permits first login and relies on user model for all subsequent authentication):
[desktop]
[[auth]]
backend=desktop.auth.backend.LdapBackend,desktop.auth.backend.AllowFirstUserDjangoBackend
This tells Hue to first check against the configured LDAP directory service, and if the username is not found in the directory, then attempt to authenticate the user with the Django user manager.
[Read more about it here](http://gethue.com/configuring-hue-multiple-authentication-backends-and-ldap/).
### 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](http://gethue.com/password-management-in-hue/).
Above works with the `AllowFirstUserBackend`, it might be different if another backend is used.
### Change your maps look and feel
The properties we need to tweak are leaflet_tile_layer and leaflet_tile_layer_attribution, that can be configured in the hue.ini file:
[desktop]
leaflet_tile_layer=https://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer/tile/{z}/{y}/{x}
leaflet_tile_layer_attribution='Tiles © Esri — Source: Esri, i-cubed, USDA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGN, IGP, UPR-EGP, and the GIS User Community'
[Read more about it here](http://gethue.com/change-your-maps-look-and-feel/).
### Configure a Proxy
We explained how to run Hue with NGINX serving the static files or under Apache. If you use another proxy, you might need to set these options:
[desktop]
# Enable X-Forwarded-Host header if the load balancer requires it.
use_x_forwarded_host=false
# Support for HTTPS termination at the load-balancer level with SECURE_PROXY_SSL_HEADER.
secure_proxy_ssl_header=false
### Configuring SSL
You can configure Hue to serve over HTTPS.
1. Configure Hue to use your private key by adding the following
options to the `hue.ini` configuration file:
ssl_certificate=/path/to/certificate
ssl_private_key=/path/to/key
2. 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
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.
### SASL
When getting a bigger result set from Hive/Impala or bigger files like images from HBase, the response requires to increase
the buffer size of SASL lib for thrift sasl communication.
[desktop]
# This property specifies the maximum size of the receive buffer in bytes in thrift sasl communication (default 2 MB).
sasl_max_buffer=2 * 1024 * 1024
### User Admin Configuration
In the `[useradmin]` section of the configuration file, you can
_optionally_ specify the following:
default_user_group::
The name of a default group that is suggested when creating a
user manually. If the LdapBackend or PamBackend are configured
for doing user authentication, new users will automatically be
members of the default group.
### Banner
You can add a custom banner to the Hue Web UI by applying HTML directly to the property, banner_top_html. For example:
banner_top_html=My company's custom Hue Web UI banner
### Splash Screen
You can customize a splash screen on the login page by applying HTML directly to the property, login_splash_html. For example:
[desktop]
[[custom]]
login_splash_html=WARNING: You are required to have authorization before you proceed.
### Custom Logo
There is also the possibility to change the logo for further personalization.
[desktop]
[[custom]]
# SVG code to replace the default Hue logo in the top bar and sign in screen
# e.g.
logo_svg=
You can go crazy and write there any SVG code you want. Please keep in mind your SVG should be designed to fit in a 160×40 pixels space. To have the same ‘hearts logo’ you can see above, you can type this code
[desktop]
[[custom]]
logo_svg=' '
Read more about it in [Hue with a custom logo](http://gethue.com/hue-with-a-custom-logo/) post.
### Storing passwords in file script
This [article details how to store passwords in a script](http://gethue.com/storing-passwords-in-script-rather-than-hue-ini-files/) launched from the OS rather than have clear text passwords in the hue*.ini files.
Some passwords go in Hue ini configuration file making them easily visible to Hue admin user or by users of cluster management software. You can use the password_script feature to prevent passwords from being visible.
### Idle session timeout
Hue now offers a new property, idle_session_timeout, that can be configured in the hue.ini file:
[desktop]
[[auth]]
idle_session_timeout=600
When idle_session_timeout is set, users will automatically be logged out after N (e.g. – 600) seconds of inactivity and be prompted to login again:
[Read more about it here](http://gethue.com/introducing-the-new-login-modal-and-idle-session-timeout/).
### Auditing
Read more about [Auditing User Administration Operations with Hue and Cloudera Navigator](http://gethue.com/auditing-user-administration-operations-with-hue-and-cloudera-navigator-2/).
## Configuration for external services
These configuration variables are under the `[hadoop]` section in
the `hue.ini` configuration file.
### Hadoop and other services
Depending on which apps you need, you need to make sure that some Hadoop services
are already setup (that way Hue can talk to them).
|-------------|--------------------------------------------------------|
| Component | Applications |
|-------------|--------------------------------------------------------|
| Editor | SQL (Hive, Impala, any database...), Pig, Spark... |
| Browsers | YARN, Oozie, Impala, HBase, Livy |
| Scheduler | Oozie |
| Dashboard | Solr, SQL (Impala, Hive...) |
|-------------|--------------------------------------------------------|
##### Hadoop Configuration
You need to enable WebHdfs or run an HttpFS server. To turn on WebHDFS,
add this to your `hdfs-site.xml` and *restart* your HDFS cluster.
Depending on your setup, your `hdfs-site.xml` might be in `/etc/hadoop/conf`.
dfs.webhdfs.enabled
true
You also need to add this to `core-site.xml`.
hadoop.proxyuser.hue.hosts
*
hadoop.proxyuser.hue.groups
*
If you place your Hue Server outside the Hadoop cluster, you can run
an HttpFS server to provide Hue access to HDFS. The HttpFS service requires
only one port to be opened to the cluster.
Also add this in `httpfs-site.xml` which might be in `/etc/hadoop-httpfs/conf`.
httpfs.proxyuser.hue.hosts
*
httpfs.proxyuser.hue.groups
*
#### Configure Oozie
Hue submits MapReduce jobs to Oozie as the logged in user. You need to
configure Oozie to accept the `hue` user to be a proxyuser. Specify this in
your `oozie-site.xml` (even in a non-secure cluster), and restart Oozie:
oozie.service.ProxyUserService.proxyuser.hue.hosts
*
oozie.service.ProxyUserService.proxyuser.hue.groups
*
#### Hive Configuration
Hue's Hive SQL Editor application helps you use Hive to query your data.
It depends on a Hive Server 2 running in the cluster. Please read
this section to ensure a proper integration.
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 (1777), as Hive makes extensive use of it.
In `hue.ini`, modify `hive_conf_dir` to point to the
directory containing `hive-site.xml`.
#### Hive and Impala High Availability (HA)
HiveServer2 and Impala support High Availability through a “load balancer”.
One caveat is that Hue’s underlying Thrift libraries reuse TCP connections in a
pool, a single user session may not have the same Impala or Hive TCP connection.
If a TCP connection is balanced away from the previously selected HiveServer2
or Impalad instance, the user session and its queries can be lost and trigger
the “Results have expired” or “Invalid session Id” errors.
To prevent sessions from being lost, you need configure the load balancer with
“source” algorithm to ensure each Hue instance sends all traffic to a single
HiveServer2/Impalad instance. Yes, this is not true load balancing, but a
configuration for failover High Availability. HiveSever2 or Impala coordinators
already distribute the work across the cluster so this is not an issue.
To enable an optimal load distribution that works for everybody, you can create
multiple profiles in our load balancer, per port for Hue clients and non-Hue
clients like Hive or Impala. You can configure non-Hue clients to distribute loads
with “roundrobin” or “leastconn” and configure Hue clients with “source”
(source IP Persistence) on dedicated ports, for example, 10015 for Hive beeline
commands, 10016 for Hue, 21051 for Hue-Impala interactions while 25003 for Impala shell.
You can configure the HaProxy to have two different ports associated with
different load balancing algorithms. Here is a sample configuration (haproxy.cfg)
for Hive and Impala HA on a secure cluster.
frontend hiveserver2_front
bind *:10015 ssl crt /path/to/cert_key.pem
mode tcp
option tcplog
default_backend hiveserver2
backend hiveserver2
balance roundrobin
mode tcp
server hs2_1 host-2.com:10000 ssl ca-file /path/to/truststore.pem check
server hs2_2 host-3.com:10000 ssl ca-file /path/to/truststore.pem check
server hs2_3 host-1.com:10000 ssl ca-file /path/to/truststore.pem check
frontend hivejdbc_front
bind *:10016 ssl crt /path/to/cert_key.pem
mode tcp
option tcplog
stick match src
stick-table type ip size 200k expire 30m
default_backend hivejdbc
backend hivejdbc
balance source
mode tcp
server hs2_1 host-2.com:10000 ssl ca-file /path/to/truststore.pem check
server hs2_2 host-3.com:10000 ssl ca-file /path/to/truststore.pem check
server hs2_3 host-1.com:10000 ssl ca-file /path/to/truststore.pem check
And here is an example for impala HA configuration on a secure cluster.
frontend impala_front
bind *:25003 ssl crt /path/to/cert_key.pem
mode tcp
option tcplog
default_backend impala
backend impala
balance leastconn
mode tcp
server impalad1 host-3.com:21000 ssl ca-file /path/to/truststore.pem check
server impalad2 host-2.com:21000 ssl ca-file /path/to/truststore.pem check
server impalad3 host-4.com:21000 ssl ca-file /path/to/truststore.pem check
frontend impalajdbc_front
bind *:21051 ssl crt /path/to/cert_key.pem
mode tcp
option tcplog
stick match src
stick-table type ip size 200k expire 30m
default_backend impalajdbc
backend impalajdbc
balance source
mode tcp
server impalad1 host-3.com:21050 ssl ca-file /path/to/truststore.pem check
server impalad2 host-2.com:21050 ssl ca-file /path/to/truststore.pem check
server impalad3 host-4.com:21050 ssl ca-file /path/to/truststore.pem check
Note: “check” is required at end of each line to ensure HaProxy can detect any
unreachable Impalad/HiveServer2 server, so HA failover can be successful. Without
TCP check, you may hit the “TSocket reads 0 byte” error when the
Impalad/HiveServer2 server Hue tries to connect is down.
After editing the /etc/haproxy/haproxy.cfg file, run following commands to
restart HaProxy service and check the service restarts successfully.
service haproxy restart
service haproxy status
Also we need add following blocks into hue.ini.
[impala]
server_port=21051
[beeswax]
hive_server_port=10016
Read more about it in the [How to optimally configure your Analytic Database for
High Availability with Hue and other SQL clients](http://gethue.com/how-to-opti
mally-configure-your-analytic-database-for-high-availability-with-hue-and-other-sql-clients) post.
### Firewall
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 8888 on the Hue Server (or the configured Hue web HTTP port)
to interact with the system.
### Files and Object Store
#### HDFS Cluster
Hue supports one HDFS cluster. That cluster should be defined
under the `[[[default]]]` sub-section.
fs_defaultfs::
This is the equivalence of `fs.defaultFS` (aka `fs.default.name`) in
Hadoop configuration.
webhdfs_url::
You can also set this to be the HttpFS url. The default value is the HTTP
port on the NameNode.
hadoop_conf_dir::
This is the configuration directory of the HDFS, typically
`/etc/hadoop/conf`.
#### S3
Hue’s filebrowser can now allow users to explore, manage, and upload data in an S3 account, in addition to HDFS.
Read more about it in the [S3 User Documentation](../user-guide/user-guide.html#s3).
In order to add an S3 account to Hue, you’ll need to configure Hue with valid S3 credentials, including the access key ID and secret access key: [AWSCredentials](http://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSGettingStartedGuide/AWSCredentials.html)
These keys can securely stored in a script that outputs the actual access key and secret key to stdout to be read by Hue (this is similar to how Hue reads password scripts). In order to use script files, add the following section to your hue.ini configuration file:
[aws]
[[aws_accounts]]
[[[default]]]
access_key_id_script=/path/to/access_key_script
secret_access_key_script= /path/to/secret_key_script
allow_environment_credentials=false
region=us-east-1
Alternatively (but not recommended for production or secure environments), you can set the access_key_id and secret_access_key values to the plain-text values of your keys:
[aws]
[[aws_accounts]]
[[[default]]]
access_key_id=s3accesskeyid
secret_access_key=s3secretaccesskey
allow_environment_credentials=false
region=us-east-1
The region should be set to the AWS region corresponding to the S3 account. By default, this region will be set to ‘us-east-1’.
Using Ceph
New end points have been added in [HUE-5420](https://issues.cloudera.org/browse/HUE-5420)
#### ADLS
Hue’s file browser can now allow users to explore, manage, and upload data in an ADLS, in addition to HDFS and S3.
Read more about it in the [ADLS User Documentation](../user-guide/user-guide.html#adls).
In order to add an ADLS account to Hue, you’ll need to configure Hue with valid ADLS credentials, including the client ID, client secret and tenant ID.
These keys can securely stored in a script that outputs the actual access key and secret key to stdout to be read by Hue (this is similar to how Hue reads password scripts). In order to use script files, add the following section to your hue.ini configuration file:
[adls]
[[azure_accounts]]
[[[default]]]
client_id_script=/path/to/client_id_script.sh
client_secret_script=/path/to/client_secret_script.sh
tenant_id_script=/path/to/tenant_id_script.sh
[[adls_clusters]]
[[[default]]]
fs_defaultfs=adl://.azuredatalakestore.net
webhdfs_url=https://.azuredatalakestore.net
Alternatively (but not recommended for production or secure environments), you can set the client_secret value in plain-text:
[adls]
[[azure_account]]
[[[default]]]
client_id=adlsclientid
client_secret=adlsclientsecret
tenant_id=adlstenantid
[[adls_clusters]]
[[[default]]]
fs_defaultfs=adl://.azuredatalakestore.net
webhdfs_url=https://.azuredatalakestore.net
### Yarn (MR2) Cluster
Hue supports one or two Yarn clusters (two for HA). These clusters should be defined
under the `[[[default]]]` and `[[[ha]]]` sub-sections.
resourcemanager_host::
The host running the ResourceManager.
resourcemanager_port::
The port for the ResourceManager REST service.
logical_name::
NameNode logical name.
submit_to::
To enable the section, set to True.
### Impala Configuration
In the `[impala]` section of the configuration file, you can
_optionally_ specify the following:
server_host::
The hostname or IP that the Impala Server should bind to. By
default it binds to `localhost`, and therefore only serves local
IPC clients.
[LDAP or PAM pass-through authentication with Hive or Impala and Impersonation
](http://gethue.com/ldap-or-pam-pass-through-authentication-with-hive-or-impala/).
### Hive Configuration
In the `[beeswax]` section of the configuration file, you can
_optionally_ specify the following:
beeswax_server_host::
The hostname or IP that the Hive Server should bind to. By
default it binds to `localhost`, and therefore only serves local
IPC clients.
hive_conf_dir::
The directory containing your `hive-site.xml` Hive
configuration file.
### JDBC
Use the query editor with any [JDBC](http://gethue.com/custom-sql-query-editors/) or Django-compatible database.
### Oozie Configuration
In the `[liboozie]` section of the configuration file, you should
specify:
oozie_url::
The URL of the Oozie service. It is the same as the `OOZIE_URL`
environment variable for Oozie.
### Solr Configuration
In the `[search]` section of the configuration file, you should
specify:
solr_url::
The URL of the Solr service.
### HBase Configuration
In the `[hbase]` section of the configuration file, you should
specify:
hbase_clusters::
Comma-separated list of HBase Thrift servers for clusters in the format of "(name|host:port)".
### 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.
# 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.
## 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](http://gethue.com/easier-administration-of-hue-with-the-new-threads-and-metrics-pages/)
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](http://gethue.com/easier-administration-of-hue-with-the-new-threads-and-metrics-pages/)
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
](http://gethue.com/ldap-or-pam-pass-through-authentication-with-hive-or-impala/).
### 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.
| Username | A user name that contains only letters, numbers, and underscores;
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.
|
| 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.
For non-superusers, the user and group of the directory are
username. For superusers, the user and group are username and
supergroup. |
3. Click **Add User** to save the information you specified and close
the **Add User** wizard or click **Next**.
4. In the **Names and Groups** screen, add optional information.
| First name and Last name | The user's first and last name.
|
| E-mail address | The 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). |
5. Click **Add User** to save the information you specified and close
the **Add User** wizard or click **Next**.
6. 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. |
7. 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:
| Username | The user name. |
| Distinguished name | Indicate 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. |
3. 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.
### 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. |
| Members | The users in the group. Check user names or check Select all. |
| Permissions | The applications the users in the group can access. Check
application names or check Select all. |
3. 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.
#### 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. |
3. 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](http://gethue.com/how-to-manage-permissions-in-hue/).
## 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.
## 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.
# Using Hue
After installation, you can use Hue by navigating to `http://myserver:8888/`.
The link:user-guide/index.html[user guide] will help users go through the various installed applications.
## Supported Browsers
The two latest LTS versions of each browsers:
* IE/Edge
* Safari
* Chrome
* Firefox
## Feedback
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. Please include the
logs as a zip (or cut and paste the ones that look relevant) and send those with
your bug reports.