can ACI act as a NTP server for my DC ressources?

[tlequertier]

Hello,

i want my ACI Fabric (2.0(1l) be a NTP server for all my DC ressources (servers, VMs, LB, etc..)

ACI Fabric itself will get its clock from a stratum 4 server (in fact my CE routers).

Could ACI act as a stratum 5 in regards of my DC ressources?

if yes, which device will play the role or NTP server : the Leafs? the Spines? the APICs?  (Are Spines to consider as stratum 5 and my leafs as Stratum 6) ?  or is the ACI Fabric to be considered as a whole NTP serveR?

I don' t find any examples how to configure ACI Fabric as a NTP Server itself.

Thanks a for your advices !

[RedNectar]

ACI Fabric does not currently support an NTP Server function.  I don't believe it is on any roadmap I've seen either.

When you consider that an APIC cluster could (in a stretched fabric or multi-pod scenario) have APICs in different time zones, having an APIC as an NTP server may not be a desirable feature anyway.

HTH

CW

[#3]

When you consider that an APIC cluster could (in a stretched fabric or multi-pod scenario) have APICs in different time zones, having an APIC as an NTP server may not be a desirable feature anyway.

Timezones are a non-issue with NTP.  NTP operates entirely at UTC.  All Timezone information is applied by individual systems on top of it, but it has no meaning within NTP.

There is no real reason that ACI fabric switches couldn't serve as NTP time sources for other devices, other than Cisco is still lacking big chunks of functionality in it.

[rasesh.patel@tmx.com]

Version 3.1i has option for NTP Server. 

[jamie-nicol]

How is the NTP server configured?

I've followed the instructions here, which aren't very clear.

I have this on my leaf node:

LEAF-01# show ntp server-info
   ServerState: enabled
   MasterMode : disabled         Stratum : 8

If i configure a pervasive IP address on either a Bridge-Domain or an EPG, there is no reponse from it:

ntpdate -d -q 10.x.x.11     (where 10.x.x.11 is the pervasive IP)
transmit(10.x.x.11)
transmit(10.x.x.11)

Contrast this with an IP that does respond to NTP:

ntpdate -d -q 10.x.x.254
transmit(10.x.x.254)
receive(10.x.x.254)

What am I missing here?

[peterzhang]

Make sure the SVIs are up and operational on the switches. If they are not deployed to the switch, that's because there is no EPGs deployed. You can configure a dummy static path binding in lab environment to get around it.

However, in production environment, you still won't find the same SVI deployed on every single leaf switches, they are only deployed "as needed". This could be a reason why it might not be a good idea to use ACI as NTP, because your NTP address could be removed unintentionally.