Vmkernel IP in DNS ?

jibbajabba

Asked that on the vmware forums as well, but they don't seem to understand what I am asking

Someone asked me for some advice as his vmotion stops working every now and then. He doesn't have DNS in his lab environment and he therefore uses hostfiles (2 hosts only so not a big deal).

Now I checked the hostfiles (on every host and vcenter) and they show

192.168.0.10 vcenter.domain.com
192.168.0.20 esx1.domain.com
192.169.0.21 exs1.domain.com
192.168.0.30 esx2.domain.com
192.168.0.31 esx2.domain.com

The 21/31 addresses are his vmkernel IP.

He told me that vmware told him to do that but surely that is rubbish?

First time I heard you add the kernel ip to the DNS. Surely it would roundrobbin with the hosts ip which is why he gets random problems ?

Or am I missinformed here ?

dynamik

Why do you think round-robin would be taking place?

jibbajabba

dynamik wrote: »

Why do you think round-robin would be taking place?

I don't 100% know if the hostfile simply goes from top to bottom, but when you configure an A-Record in a DNS server with multiple IPs it will round robin.

dynamik

Pretty sure that's a function of the DNS server; I don't think the host file works that way. I'm not saying that's setup correctly, but I think the way it works would be consistent (i.e. either the first or last match). Why doesn't he just give the kernel IP a different hostname and see if that helps at all?

jibbajabba

The question is whether the kernel ip even have to be setup in DNS

HeroPsycho

ESX or ESXi?

jibbajabba

HeroPsycho wrote: »

ESX or ESXi?

The vmkernel IP is required for the iSCSI initiator and vmotion so I don't think it makes a difference ..... Like I say - I am not looking for vmotion support but rather for the answer whether the vmkernel IP needs to be registered in DNS or not ... I don't think vmotion works differently only ESXi or ESX. But for the sake of argument - ESX ...

Don't worry - nobody from vmware seem to be able to answer the question either as everybody seems to want to troubleshoot a problem which doesn't exist ..

This should be a simple 'yes' or 'no' really ...

HeroPsycho

OK, well, since you don't think I can help...

astorrs

Simple "No"

jibbajabba

HeroPsycho wrote: »

OK, well, since you don't think I can help...

I apologize, I didn't want to be snippy or come across like an arogant git. Two weeks ago my mate asked vmware the same question. The ticket is still open.

Basically every time we ask a simple question people try to over analyze it or trying to fix a vmotion problem which we probably know what the problem is ourselves.

No offence, your question felt like talking to the vmware guy again.

I asked whether the vmkernel IP needs to be registered in DNS and you asked me whether we are using ESX or ESXi.

The question was regarding a fundamental part of ESX which is no different to ESXi.

But I am willing to learn and maybe I still don't 100% understand ESXi.

So you are saying that ESX and ESXi are different then in terms of the vmkernel config.

How ? Does it mean you add DNS for the vmkernel on ESX but not ESXi or via versa ?

astorrs wrote: »

Simple "No"

Thanks.

dales

personally I think that the VMkernal should be registered in DNS as vmotion is very dependant on dns, the main issue is having vmotion and iscsi presumably on your production lan it should be on a seperate subnet and physical lan.

At the moment virtualcenter or whatever is querying the hostfile for the location of esx1/2 but there is no way of telling it what ip has what service on it, I would assume that you might get the odd validation error when trying to migrate guests over hosts.

HeroPsycho

Gomjaba wrote: »

I apologize, I didn't want to be snippy or come across like an arogant git. Two weeks ago my mate asked vmware the same question. The ticket is still open.

Basically every time we ask a simple question people try to over analyze it or trying to fix a vmotion problem which we probably know what the problem is ourselves.

No offence, your question felt like talking to the vmware guy again.

I asked whether the vmkernel IP needs to be registered in DNS and you asked me whether we are using ESX or ESXi.

The question was regarding a fundamental part of ESX which is no different to ESXi.

But I am willing to learn and maybe I still don't 100% understand ESXi.

So you are saying that ESX and ESXi are different then in terms of the vmkernel config.

How ? Does it mean you add DNS for the vmkernel on ESX but not ESXi or via versa ?



Thanks.

The reason I asked was since ESXi doesn't have service console ports, and if you shared VMotion with the same kernel port as the kernel port for management, only then would it need to be registered in DNS, and that's more because it's the equivalent of the service console in ESX. Otherwise, no, you don't need the kernel port registered in DNS.

HeroPsycho

dales wrote: »

personally I think that the VMkernal should be registered in DNS as vmotion is very dependant on dns, the main issue is having vmotion and iscsi presumably on your production lan it should be on a seperate subnet and physical lan.

At the moment virtualcenter or whatever is querying the hostfile for the location of esx1/2 but there is no way of telling it what ip has what service on it, I would assume that you might get the odd validation error when trying to migrate guests over hosts.

It's not a matter of personal belief. Vmotion doesn't require the kernel port for VMotion be registered in DNS, period. Where DNS is involved is the ESX servers resolving the service console ports, or in the case of ESXi the kernel management ports.

Once the vCenter server can resolve the management ports, it can query the ESX server to know which to use.

jibbajabba

HeroPsycho wrote: »

Vmotion doesn't require the kernel port for VMotion be registered in DNS, period.

That's all I wanted to know

Thanks.

blargoe

HeroPsycho is right on the money as usual

jibbajabba

Sure is, I still don't quite understand what the difference is when using ESX or ESXi to be honest.

HeroPsycho

Gomjaba wrote: »

Sure is, I still don't quite understand what the difference is when using ESX or ESXi to be honest.

Like i said, it only would have made the exception of if you shared Vmotion with the kernel port group that is used for management of the ESXi box by vCenter, hence why I asked.

jibbajabba

HeroPsycho wrote: »

Like i said, it only would have made the exception of if you shared Vmotion with the kernel port group that is used for management of the ESXi box by vCenter, hence why I asked.

Ah now I get it