Networking and Security Requirements

The following components are supported by the indicated versions of Transport Layer Security (TLS):

The hosts in a Cloudera Manager deployment must satisfy the following networking and security requirements:

• Networking Protocols Support
  CDH requires IPv4. IPv6 is not supported and must be disabled.

  See also Configure Network Names.

• Multihoming Support

  Multihoming CDH or Cloudera Manager is not supported outside specifically certified Cloudera partner appliances. Cloudera finds that current Hadoop architectures combined with modern network infrastructures and security practices remove the need for multihoming. Multihoming, however, is beneficial internally in appliance form factors to take advantage of high-bandwidth InfiniBand interconnects.

  Although some subareas of the product may work with unsupported custom multihoming configurations, there are known issues with multihoming. In addition, unknown issues may arise because multihoming is not covered by our test matrix outside the Cloudera-certified partner appliances.

• Entropy

  Data at rest encryption requires sufficient entropy to ensure randomness.

  See entropy requirements in Data at Rest Encryption Requirements.

• Cluster hosts must have a working network name resolution system and correctly formatted /etc/hosts file. All cluster hosts must have properly configured forward and reverse host resolution through DNS. The /etc/hosts files must:
  • Contain consistent information about hostnames and IP addresses across all hosts
  • Not contain uppercase hostnames
  • Not contain duplicate IP addresses

  Cluster hosts must not use aliases, either in /etc/hosts or in configuring DNS. A properly formatted /etc/hosts file should be similar to the following example:

  127.0.0.1 localhost.localdomain localhost
  192.168.1.1 cluster-01.example.com cluster-01
  192.168.1.2 cluster-02.example.com cluster-02
  192.168.1.3 cluster-03.example.com cluster-03 

• In most cases, the Cloudera Manager Server must have SSH access to the cluster hosts when you run the installation or upgrade wizard. You must log in using a root account or an account that has password-less sudo permission. For authentication during the installation and upgrade procedures, you must either enter the password or upload a public and private key pair for the root or sudo user account. If you want to use a public and private key pair, the public key must be installed on the cluster hosts before you use Cloudera Manager.

  Cloudera Manager uses SSH only during the initial install or upgrade. Once the cluster is set up, you can disable root SSH access or change the root password. Cloudera Manager does not save SSH credentials, and all credential information is discarded when the installation is complete.

• The Cloudera Manager Agent runs as root so that it can make sure that the required directories are created and that processes and files are owned by the appropriate user (for example, the hdfs and mapred users).
• Security-Enhanced Linux (SELinux) must not block Cloudera Manager or CDH operations.
• Firewalls (such as iptables and firewalld) must be disabled or configured to allow access to ports used by Cloudera Manager, CDH, and related services.
• For RHEL and CentOS, the /etc/sysconfig/network file on each host must contain the correct hostname.
• Cloudera Manager and CDH use several user accounts and groups to complete their tasks. The set of user accounts and groups varies according to the components you choose to install. Do not delete these accounts or groups and do not modify their permissions and rights. Ensure that no existing systems prevent these accounts and groups from functioning. For example, if you have scripts that delete user accounts not in a whitelist, add these accounts to the list of permitted accounts. Cloudera Manager, CDH, and managed services create and use the following accounts and groups: