NTP server on a bridged ethernet container

[andrea]

After browsing the forums and googling around, I'm still not sure about the correct approach for a NTP server inside a container.

The need is for a ntpd daemon running in a OpenVZ container with bridged ethernet (vmbr0) and acting as time server for a local network. Just installing and running ntpd with proper "broadcast" configuration seems to work and sync time either in the container and in the clients pointing to it. (container log confirms the sync with time server pool)

However, OpenVZ container running ntpd does NOT has the sys_time capability on. So my doubt is, which time is managing the ntpd daemon, the container one OR the hardware node one, which is already running ntpd?

Also, if time in container syncs correctly without sys_time capability, it appears a bridged container behaves differently than others, but i was unable to find useful documentation.

Any help pointing me in the right direction would be greatly appreciated
Cheers,
Andrea

 

[dietmar]

Also, if time in container syncs correctly without sys_time capability...

You can enable that - see 'man vzctl'

 

[andrea]

Thanks Dietnar,

yes, the capability can be set, however the question was more keen to understand why a container sync time without such capability and if there are differences running NTPD in a bridged container.

 

[dietmar]

yes, the capability can be set, however the question was more keen to understand why a container sync time without such capability and if there are differences running NTPD in a bridged container.

The container uses the host time (and the host have ntpd running). I do not see how network mode (bridged/venet) relate to this at all.

 

[andrea]

Dietmar,

you have right, that's the reason I do not understand why a container can use ntpd, and sync Kernel, without capability. The only difference was the network type.