CephFS

This guide describes how to configure Alluxio with CephFS as the under storage system. Alluxio supports two different implementations of under storage system for CephFS:

Prerequisites

Deploy Alluxio binary package

The Alluxio binaries must be on your machine. You can either compile Alluxio, or download the binaries locally.

Install Dependences

According to ceph packages install to install below packages:

cephfs-java
libcephfs_jni
libcephfs2

Make symbolic links

$ ln -s /usr/lib64/libcephfs_jni.so.1.0.0 /usr/lib64/libcephfs_jni.so
$ ln -s /usr/lib64/libcephfs.so.2.0.0 /usr/lib64/libcephfs.so
$ java_path=`which java | xargs readlink | sed 's#/bin/java##g'`
$ ln -s /usr/share/java/libcephfs.jar $java_path/jre/lib/ext/libcephfs.jar

Download CephFS Hadoop jar

$ curl -o $java_path/jre/lib/ext/hadoop-cephfs.jar -s https://download.ceph.com/tarballs/hadoop-cephfs.jar

Basic Setup

Configure Alluxio to use under storage systems by modifying conf/alluxio-site.properties and conf/core-site.xml. If them do not exist, create the configuration files from the templates

$ cp conf/alluxio-site.properties.template conf/alluxio-site.properties
$ cp conf/core-site.xml.template conf/core-site.xml

cephfs

Modify conf/alluxio-site.properties to include:

alluxio.underfs.cephfs.conf.file=<ceph-conf-file>
alluxio.underfs.cephfs.mds.namespace=<ceph-fs-name>
alluxio.underfs.cephfs.mount.point=<ceph-fs-dir>
alluxio.underfs.cephfs.auth.id=<client-id>
alluxio.underfs.cephfs.auth.keyring=<client-keyring-file>

cephfs-hadoop

Modify conf/alluxio-site.properties to include:

alluxio.underfs.hdfs.configuration=${ALLUXIO_HOME}/conf/core-site.xml

Modify conf/core-site.xml to include:

<configuration>
  <property>
    <name>fs.default.name</name>
    <value>ceph://mon1,mon2,mon3/</value>
  </property>
  <property>
    <name>fs.defaultFS</name>
    <value>ceph://mon1,mon2,mon3/</value>
  </property>
  <property>
    <name>ceph.data.pools</name>
    <value>${data-pools}</value>
  </property>
  <property>
    <name>ceph.auth.id</name>
    <value>${client-id}</value>
  </property>
  <property>
    <name>ceph.conf.options</name>
    <value>client_mount_gid=${gid},client_mount_uid=${uid},client_mds_namespace=${ceph-fs-name}</value>
  </property>
  <property>
    <name>ceph.root.dir</name>
    <value>${ceph-fs-dir}</value>
  </property>
  <property>
    <name>ceph.mon.address</name>
    <value>mon1,mon2,mon3</value>
  </property>
  <property>
    <name>fs.AbstractFileSystem.ceph.impl</name>
    <value>org.apache.hadoop.fs.ceph.CephFs</value>
  </property>
  <property>
    <name>fs.ceph.impl</name>
    <value>org.apache.hadoop.fs.ceph.CephFileSystem</value>
  </property>
  <property>
    <name>ceph.auth.keyring</name>
    <value>${client-keyring-file}</value>
  </property>
</configuration>

Running Alluxio Locally with CephFS

Start up Alluxio locally to see that everything works.

$ ./bin/alluxio format
$ ./bin/alluxio-start.sh local

This should start an Alluxio master and Alluxio worker. You can see the master UI at http://localhost:19999.

cephfs

An CephFS location can be mounted at a nested directory in the Alluxio namespace to have unified access to multiple under storage systems. Alluxio's Command Line Interface can be used for this purpose.

Issue the following command to use the ufs cephfs:

$ ./bin/alluxio fs mkdir /mnt/cephfs
$ ./bin/alluxio fs mount /mnt/cephfs cephfs://mon1\;mon2\;mon3/

Run a simple example program:

$ ./bin/alluxio runTests --path cephfs://mon1\;mon2\;mon3/

Visit your cephfs to verify the files and directories created by Alluxio exist.

You should see files named like: In cephfs, you can visit cephfs with ceph-fuse or mount by POSIX APIs. Mounting CephFS

${ceph-fs-dir}/default_tests_files/Basic_CACHE_THROUGH

In Alluxio, you can visit the nested directory in the Alluxio. Alluxio's Command Line Interface can be used for this purpose.

/mnt/cephfs/default_tests_files/Basic_CACHE_THROUGH