Best Practices for time management in RHEL/CentOS 7 in VMware

ntpvmware-esxi

NTP, CHRONY, OPEN-vm-tools… Best Practices for time management in RHEL/CentOS 7?

Hello.

I am (finally) working on creating a CentOS 7 VMware (ESXi) Template – currently ESXi/vCenter 5.5+.

Past usage of time management within a guest has varied and we have utilized KB 1006427 (https://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1006427) however it has not been updated for RHEL 7.

My Google-fu is failing me.

I am utilizing open-vm-tools and just looking for best practices for time management within the Linux guest.

Best Answer

I understood that if your VMs get switched on and off often (as in auto-scaling) chronyd is the better service:

https://chrony.tuxfamily.org/faq.html#_how_does_code_chrony_code_compare_to_code_ntpd_code

If your computer is connected to the Internet only for few minutes at a time, the network connection is often congested, you turn your computer off or suspend it frequently, the clock is not very stable (e.g. there are rapid changes in the temperature or it’s a virtual machine), or you want to use NTP on an isolated network with no hardware reference clocks in sight, chrony will probably work much better for you.

If always on, then ntpd, as Paul mentions.

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