How to generate entropy in SLES 11 SP1 and Later
This document (7011351) is provided subject to the disclaimer at the end of this document.
SUSE Linux Enterprise Server 11 Service Pack 2 (SLES 11 SP2)
SUSE Linux Enterprise Server 11 Service Pack 3 (SLES 11 SP3)
SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)
SUSE Linux Enterprise Server 12 Service Pack 1 (SLES 12 SP1)
SUSE Linux Enterprise Server 12 Service Pack 2 (SLES 12 SP2)
Doing cat /dev/random returns only a few characters (instead of a constant stream).
Entropy value from command /sbin/sysctl kernel.random.entropy_avail is less than 1000.
Steps to install and enable haveged:
- Install haveged. e.g zypper in haveged
- On SLES11, start haveged. /etc/init.d/haveged start
- On SLES12 and later, start haveged: systemctl start haveged
- On SLES11, enable haveged to start at boot. chkconfig haveged on
- On SLES12 and later, enable haveged to start on boot: systemctl enable haveged
- Reboot the SLES server. The boot process generates a lot of entropy. If you reboot twice, you get even more entropy.
- Verify by doing:
You should see a continual stream of random characters.
/sbin/sysctl kernel.random.entropy_availThis number should be 1000+.
For more information see: http://www.issihosts.com/haveged/
This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.
- Document ID:7011351
- Creation Date: 12-Nov-2012
- Modified Date:03-Mar-2020
- SUSE Linux Enterprise Server
For questions or concerns with the SUSE Knowledgebase please contact: firstname.lastname@example.org