How to sync time on host wake-up within VirtualBox?

Solution 1:

The documentation lacks some details here.

What VirtualBox does every 10 seconds is just slight adjustement (something like 0.005 seconds). Only when the time difference reaches a threshold (20 minutes by default) a "real" resync is done.

You can reduce the thresold (i.e. to 10 seconds) with the following command:

VBoxManage guestproperty set <vm-name> "/VirtualBox/GuestAdd/VBoxService/--timesync-set-threshold" 10000

Solution 2:

Summarizing answers of @zilupe and @Slobodan Kovacevic, solution is to add following to Vagrantfile:

config.vm.provider 'virtualbox' do |vb|
   vb.customize [ "guestproperty", "set", :id, "/VirtualBox/GuestAdd/VBoxService/--timesync-set-threshold", 1000 ]
end

This will synchronize clocks each time when desync becomes > 1s (1000ms)

Solution 3:

I give an other solution to sync time between guest & host without installing Virtualbox guest addition:

1. install ntp on your guest, and de-comment these lines in /etc/ntp.conf:

   disable auth
   broadcastclient
   

Then, restart ntp with service ntp restart

2. Active broadcast on your host:

   • For Linux users, edit your /etc/ntp.conf file and configure broadcast (you must adapt IP):

     broadcast 192.168.123.255

   • For Windows users, activate the "Windows Time" service. You can then read this page to configure it to broadcast time

   Then, restart time service on host.

Solution 4:

For me to get timesync working I had to do this:

vboxmanage setextradata «machine-name» "VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" 0

It turns the timesync on. It was, for some reason, off.

Solution 5:

I found a solution:

1. install ntpdate
2. add "s" permission for ntpdate, this allows non-root users to run ntpdate as root: sudo chmod u+s /usr/sbin/ntpdate
3. add one line in ~/.bashrc: ntpdate -u ntp.ubuntu.com

After that, each time you login to the linux system, the time will be sync once.