CiscoKid1981
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Contributor

Is DNS a requirement for vMotion?

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Is DNS a requirement for VMotion?

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RParker
Immortal
Immortal

OH, and for the record, you need to use lifelines before you answer a question, not after, or you will be kicked off Who want's to be a millionaire with those lifelines remaining.

Oops my mistake. But technically if you give your answer BEFORE you declare use of such lifelines, you lose them if your answer is incorrect. And since I gave my final answer, and assuming my answer was the truth, I would still retain my life lines. So I was giving my status so those of us keeping score knew my lifelines were intact.

But on are you smarter than a 5th grader... then you at least get a save, which is where you come in. Smiley Happy

And boys and girls get out your canvase and your ink, because I am about to paint a scenario.

I've been performing vMotions without an authoritative DNS structure just using the hosts file for a while now. This is my understanding of how it works, but please don't just take my word for it. I may be wrong.

VM Ware 2007, yes we support Host files, DNS not required.

I use hosts, and I call VM Ware to complain that vmotion isn't working. I then deduce that my servers can't communicate due to some clerical error in the hosts entry. so now VM Ware basically says, for future reference we should probably require DNS to alleviate errors, and since it's done automatically, and it needs SOME hosts to function and can't rely on users to be quick enough or thorough to check to make sure you don't any words out :smileyalert: then they FORCE users and techs alike to ensure proper use of their product that NOW DNS is required, because it's been proven 2002, that people just can't be trusted.

VM Ware 2009. DNS is NOW required.

That's how I see it. It became a matter of principle to require the use of DNS, otherwise THEIR product would rely on proper documentation, and since you can't design a system to be dependent on users, you CAN design it to work with known systems that work, hence DNS.

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AWo
Immortal
Immortal

Name resolution is needed, but if you can't use DNS you can use the local host files instead.


If you found this information useful, please consider awarding points for "Correct" or "Helpful" replies. Thanks!!


AWo

VCP / vEXPERT 2009

vExpert 2009/10/11 [:o]===[o:] [: ]o=o[ :] = Save forests! rent firewood! =
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RParker
Immortal
Immortal

Is DNS a requirement for vMotion?

Yes, I disagree with AWO, simply because the Virtual Center needs to ALSO locate those servers for vmotion to work, adding this LOCALLY to an ESX wouldn't allow the VC to 'see' those servers via name resolution unless DNS is working.

So my final answer is: YES (I still have 3 life lines)

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AWo
Immortal
Immortal

What about using the host file on the VC server, as well?

That should do it if there's no DNS, shouldn't it?


If you found this information useful, please consider awarding points for "Correct" or "Helpful" replies. Thanks!!


AWo

VCP / vEXPERT 2009

vExpert 2009/10/11 [:o]===[o:] [: ]o=o[ :] = Save forests! rent firewood! =
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RParker
Immortal
Immortal

What about using the host file on the VC server, as well?

That should do it if there's no DNS, shouldn't it?

Yes but who is going to update EVERY /etc/hosts file AND hosts file on Windows, EACH time?

DNS will solve the problem, probably why they require it.. to avoid potential problems in mistyping or forgetting to update... That's a lot of overhead. Wouldn't it be easier to simply enable DNS?

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AWo
Immortal
Immortal

Of course, DNS is the most practical solution, but he asked if it is necessary and not what is the most practical solution. That's why I wrote name resolution is necessary but if you can't use DNS then you can come along with the local hosts file.


If you found this information useful, please consider awarding points for "Correct" or "Helpful" replies. Thanks!!


AWo

VCP / vEXPERT 2009

vExpert 2009/10/11 [:o]===[o:] [: ]o=o[ :] = Save forests! rent firewood! =
ThatVaiGuy
Contributor
Contributor

Okay, all this discussion sounds well and good and all but...

I have just setup my test environment at home and could not setup HA. The reason was that I was not yet done configuring everything, and was relying on a router (think linksys) without proper DNS so the servers couldn't see each other. I modified the hosts file to allow the servers to see each other and Voila! vMotion and HA started working without error.

Now, I'm not an expert, but lets think about this for a minute. DNS hosts A records, PTR records, CNAME records and such. It is not responsible for the routing to a given ESX host, just the 411 style name to number look up. After that look up happens, DNS is no longer involved. vCenter doesn't need an active DNS structure to see the host servers if they're already connected and managed by the vpxuser / agent, and what would a vMotion be updating DNS for anyway? vMotion does not change the IP address of the Guest, so where does DNS come into play? Well, it comes into play when vpxuser receives a command from vCenter and issues a vMotion request to an ESX server, the server looks up DNS; gets the IP of the new ESX box to vMotion to and makes a connection. If i have this all wrong, please somebody correct me.

I've been performing vMotions without an authoritative DNS structure just using the hosts file for a while now. This is my understanding of how it works, but please don't just take my word for it. I may be wrong.

OH, and for the record, you need to use lifelines before you answer a question, not after, or you will be kicked off Who want's to be a millionaire with those lifelines remaining.

Questions, Comments, Points? Smiley Happy

Ed

RParker
Immortal
Immortal

OH, and for the record, you need to use lifelines before you answer a question, not after, or you will be kicked off Who want's to be a millionaire with those lifelines remaining.

Oops my mistake. But technically if you give your answer BEFORE you declare use of such lifelines, you lose them if your answer is incorrect. And since I gave my final answer, and assuming my answer was the truth, I would still retain my life lines. So I was giving my status so those of us keeping score knew my lifelines were intact.

But on are you smarter than a 5th grader... then you at least get a save, which is where you come in. Smiley Happy

And boys and girls get out your canvase and your ink, because I am about to paint a scenario.

I've been performing vMotions without an authoritative DNS structure just using the hosts file for a while now. This is my understanding of how it works, but please don't just take my word for it. I may be wrong.

VM Ware 2007, yes we support Host files, DNS not required.

I use hosts, and I call VM Ware to complain that vmotion isn't working. I then deduce that my servers can't communicate due to some clerical error in the hosts entry. so now VM Ware basically says, for future reference we should probably require DNS to alleviate errors, and since it's done automatically, and it needs SOME hosts to function and can't rely on users to be quick enough or thorough to check to make sure you don't any words out :smileyalert: then they FORCE users and techs alike to ensure proper use of their product that NOW DNS is required, because it's been proven 2002, that people just can't be trusted.

VM Ware 2009. DNS is NOW required.

That's how I see it. It became a matter of principle to require the use of DNS, otherwise THEIR product would rely on proper documentation, and since you can't design a system to be dependent on users, you CAN design it to work with known systems that work, hence DNS.

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ThatVaiGuy
Contributor
Contributor

Ed Sings: The VM's Connected to the...v Switch, the vSwitch's connected to the...p Nic... the pNic's connected on...Lan 3, Now why doesn't thiscrap work! Do Do!

Jeff Foxworthy just gave me an A in class for that song, then said, now back to the game show! :smileycool:

And yes, I agree to your deductions about how VMware probably came up with the requirement in vSphere, I was only adding my 2 cents for version 3.5 since that was what the discussion is under. Considering I just failed my VCP exam 2 weeks ago, what do you say Mr. vExpert to my comment about host files, DNS, and the logic behind the madness? Sound accurate?

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RParker
Immortal
Immortal

Jeff Foxworthy just gave me an A in class for that song, then said, now back to the game show!

If it were American Idol you would be given the old heave ho.. Smiley Happy

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CiscoKid1981
Contributor
Contributor

You get the points just for sheer force of will Parker.

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ThatVaiGuy
Contributor
Contributor

Damn! I was really looking forward to finally getting some points.

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RParker
Immortal
Immortal

Damn! I was really looking forward to finally getting some points.

My time to sing: na na na na .. ring around the posey...

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ThatVaiGuy
Contributor
Contributor

Jerk! :smileygrin:

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RParker
Immortal
Immortal

You get the points just for sheer force of will Parker.

Good now my campaign to become a full Jedi master is almost complete, master yodda will be so proud.. Smiley Happy

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AWo
Immortal
Immortal

I'll leave, that'll must be insiders....


AWo

VCP / vEXPERT 2009 but still not knowing what is going on here....

vExpert 2009/10/11 [:o]===[o:] [: ]o=o[ :] = Save forests! rent firewood! =
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ThatVaiGuy
Contributor
Contributor

Man, all that detail I went into and not even a helpful award. You suck! :smileylaugh:

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RParker
Immortal
Immortal

Man, all that detail I went into and not even a helpful award. You suck!

It was helpful... in proving my case.. :smileylaugh:

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ThatVaiGuy
Contributor
Contributor

Master Yoda? Jedi Master?! You points theif! You turned to the dark side long ago. ONly Hatred and greed are your ways now. The boy you once knew, consumed by the dark side he has become. Lord Sidius!

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RParker
Immortal
Immortal

Master Yoda? Jedi Master?! You points theif! You turned to the dark side long ago. ONly Hatred and greed are your ways now. The boy you once knew, consumed by the dark side he has become. Lord Sidius!

“Fear is the path to the dark side. Fear leads to anger. Anger leads to hate. Hate leads to suffering.” --Yoda

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