Operating System Requirements

The following topics describe the operating system requirements for Cloudera software:

Software Dependencies

  • Python - Cloudera Enterprise 6, with the exception of Hue, is supported on the Python version that is included in the operating system by default, as well as higher versions, but is not compatible with Python 3.0 or higher.

    For example, Cloudera Enterprise 6 requires Python 2.6 or higher on RHEL 6 compatible operating systems, but requires Python 2.7 or higher on RHEL 7 compatible operating systems.

    Hue in CDH 6 requires Python 2.7 or higher on all operating systems. For RHEL 6 compatible operating systems running Hue, you must manually install Python 2.7.

    Python 3 is not supported.

  • Perl - Cloudera Manager requires perl.
  • python-psycopg2 - Cloudera Manager 6 has a dependency on the package python-psycopg2. Hue in CDH 6 requires a higher version of psycopg2 than is required by the Cloudera Manager dependency. For more information, see Installing the psycopg2 Python Package.
  • iproute package - Cloudera Enterprise 6 has a dependency on the iproute package. Any host that runs the Cloudera Manager Agent requires the package. The required version varies depending on the operating system:
    iproute package
    Operating System iproute version
    RHEL 7 Compatible iproute-3.10
    RHEL 6 Compatible iproute-2.6
    SLES 12 SP2, SP3 iproute2-3.12

CDH and Cloudera Manager Supported Operating Systems

CDH provides 64-bit packages for select versions of RHEL-compatible, SLES, and Ubuntu operating systems.

Points to note:
  • Red Hat only supports specific upgrades from RHEL 6 to 7. Contact your OS vendor and review the Red Hat article What are the supported use cases for upgrading to RHEL 7?.
  • Cloudera does not support CDH cluster deployments in Docker containers.
  • Cloudera Enterprise, with the exception of Cloudera Navigator Encrypt, is supported on platforms with Security-Enhanced Linux (SELinux) enabled and in enforcing mode. Cloudera is not responsible for policy support or policy enforcement. If you experience issues with SELinux, contact your OS provider.

Operating System Support for CDSW Gateway Hosts

A Gateway host that is dedicated to running Cloudera Data Science Workbench must use RHEL/CentOS 7.2 even if the remaining hosts in your cluster are running any of the other CDH and Cloudera Manager Supported Operating Systems. All hosts must run the same version of the Oracle JDK.

CDH and Cloudera Manager 6.0.x Supported Operating Systems

Operating System Version (bold=new)
RHEL-compatible

RHEL/CentOS/OL with RHCK kernel

7.5, 7.4, 7.3, 7.2

6.10, 6.9 , 6.8

Oracle Linux (OL)

7.4, 7.3, 7.2 (UEK default)

SUSE Linux Enterprise Server
SLES

12 SP3, 12 SP2

Ubuntu
Ubuntu

16.04 LTS (Xenial)

Filesystem Requirements

Supported Filesystems

The Hadoop Distributed File System (HDFS) is designed to run on top of an underlying filesystem in an operating system. Cloudera recommends that you use either of the following filesystems tested on the supported operating systems:

  • ext3: This is the most tested underlying filesystem for HDFS.
  • ext4: This scalable extension of ext3 is supported in more recent Linux releases.
  • XFS: This is the default filesystem in RHEL 7.
  • S3: Amazon Simple Storage Service

Kudu Filesystem Requirements - Kudu is supported on ext4 and XFS. Kudu requires a kernel version and filesystem that supports hole punching. Hole punching is the use of the fallocate(2) system call with the FALLOC_FL_PUNCH_HOLE option set. For more details, see Error during hole punch test.

File Access Time

Linux filesystems keep metadata that record when each file was accessed. This means that even reads result in a write to the disk. To speed up file reads, Cloudera recommends that you disable this option, called atime, using the noatime mount option in /etc/fstab:

/dev/sdb1 /data1 ext4 defaults,noatime 0

Apply the change without rebooting:

mount -o remount /data1

Filesystem Mount Options

The filesystem mount options have a sync option that allows you to write synchronously.

Using the sync filesystem mount option reduces performance for services that write data to disks, such as HDFS, YARN, Kafka and Kudu. In CDH, most writes are already replicated. Therefore, synchronous writes to disk are unnecessary, expensive, and do not measurably improve stability.

NFS and NAS options are not supported for use as DataNode Data Directory mounts, even when using Hierarchical Storage features.

nproc Configuration

Cloudera Manager automatically sets nproc configuration in /etc/security/limits.conf, but this configuration can be overridden by individual files in /etc/security/limits.d/. This can cause problems with Apache Impala and other components.

Make sure that the nproc limits are set sufficiently high, such as 65536 or 262144.