docs/storage-openstack-swift.md

---
layout: global
title: Accessing OpenStack Swift from Spark
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Spark's support for Hadoop InputFormat allows it to process data in OpenStack Swift using the
same URI formats as in Hadoop. You can specify a path in Swift as input through a
URI of the form <code>swift://container.PROVIDER/path</code>. You will also need to set your
Swift security credentials, through <code>core-site.xml</code> or via
<code>SparkContext.hadoopConfiguration</code>.
The current Swift driver requires Swift to use the Keystone authentication method, or
its Rackspace-specific predecessor.

# Configuring Swift for Better Data Locality

Although not mandatory, it is recommended to configure the proxy server of Swift with
<code>list_endpoints</code> to have better data locality. More information is
[available here](https://github.com/openstack/swift/blob/master/swift/common/middleware/list_endpoints.py).


# Dependencies

The Spark application should include <code>hadoop-openstack</code> dependency, which can
be done by including the `hadoop-cloud` module for the specific version of spark used.
For example, for Maven support, add the following to the <code>pom.xml</code> file:

{% highlight xml %}
<dependencyManagement>
  ...
  <dependency>
    <groupId>org.apache.spark</groupId>
    <artifactId>hadoop-cloud_2.13</artifactId>
    <version>${spark.version}</version>
  </dependency>
  ...
</dependencyManagement>
{% endhighlight %}

# Configuration Parameters

Create <code>core-site.xml</code> and place it inside Spark's <code>conf</code> directory.
The main category of parameters that should be configured is the authentication parameters
required by Keystone.

The following table contains a list of Keystone mandatory parameters. <code>PROVIDER</code> can be
any (alphanumeric) name.

<table>
<thead><tr><th>Property Name</th><th>Meaning</th><th>Required</th></tr></thead>
<tr>
  <td><code>fs.swift.service.PROVIDER.auth.url</code></td>
  <td>Keystone Authentication URL</td>
  <td>Mandatory</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.auth.endpoint.prefix</code></td>
  <td>Keystone endpoints prefix</td>
  <td>Optional</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.tenant</code></td>
  <td>Tenant</td>
  <td>Mandatory</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.username</code></td>
  <td>Username</td>
  <td>Mandatory</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.password</code></td>
  <td>Password</td>
  <td>Mandatory</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.http.port</code></td>
  <td>HTTP port</td>
  <td>Mandatory</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.region</code></td>
  <td>Keystone region</td>
  <td>Mandatory</td>
</tr>
<tr>
  <td><code>fs.swift.service.PROVIDER.public</code></td>
  <td>Indicates whether to use the public (off cloud) or private (in cloud; no transfer fees) endpoints</td>
  <td>Mandatory</td>
</tr>
</table>

For example, assume <code>PROVIDER=SparkTest</code> and Keystone contains user <code>tester</code> with password <code>testing</code>
defined for tenant <code>test</code>. Then <code>core-site.xml</code> should include:

{% highlight xml %}
<configuration>
  <property>
    <name>fs.swift.service.SparkTest.auth.url</name>
    <value>http://127.0.0.1:5000/v2.0/tokens</value>
  </property>
  <property>
    <name>fs.swift.service.SparkTest.auth.endpoint.prefix</name>
    <value>endpoints</value>
  </property>
    <name>fs.swift.service.SparkTest.http.port</name>
    <value>8080</value>
  </property>
  <property>
    <name>fs.swift.service.SparkTest.region</name>
    <value>RegionOne</value>
  </property>
  <property>
    <name>fs.swift.service.SparkTest.public</name>
    <value>true</value>
  </property>
  <property>
    <name>fs.swift.service.SparkTest.tenant</name>
    <value>test</value>
  </property>
  <property>
    <name>fs.swift.service.SparkTest.username</name>
    <value>tester</value>
  </property>
  <property>
    <name>fs.swift.service.SparkTest.password</name>
    <value>testing</value>
  </property>
</configuration>
{% endhighlight %}

Notice that
<code>fs.swift.service.PROVIDER.tenant</code>,
<code>fs.swift.service.PROVIDER.username</code>,
<code>fs.swift.service.PROVIDER.password</code> contains sensitive information and keeping them in
<code>core-site.xml</code> is not always a good approach.
We suggest to keep those parameters in <code>core-site.xml</code> for testing purposes when running Spark
via <code>spark-shell</code>.
For job submissions they should be provided via <code>sparkContext.hadoopConfiguration</code>.