Hi. 64-bit Intel, virtualization hardware, two 2TiB disks, RAID-1 (software, LVM)
Read the stuff, did the tutorial, though I could have done something wrong.
The tutorials I found had me building from scratch, using virt-install, but I notice that virt-manager seems to let me build a new VM with little muss and fuss.

Downloaded CentOS-7-x86_64-DVD-1503-01.iso for it to use.
The documentation shows not exactly the screens I see, but gives the impression that when I answer a few questions, like name and size, and finally say OK, it'll load up the console and we'll do the questions, like when I built the machine originally, and set up a guest CentOS, but it just build the VM, give me an
/var/lib/libvrt/images/centos7.0.qcow2
When to start it from virt-manager, it says it can't boot,

booting from Hard Disk
Boot failed: not a bootable disk

What to do?
Where do I go from here?

Shooting in the dark, but this happens to me when KVM (or qemu, or libvirt) doesn't understand that this is a qcow2 file.

You can check this using virt-manager by going to the "information" screen of your virtual machine, selecting the disk and opening the advanced options. You should see the disk format; if it's blank or anything else than qcow2, set it to qcow2.

Or use virsh edit <domain name> and find the place where the disk is defined. You should see something like
If the type is not qcow2, correct it.

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Just keeping in touch.
Everything checks out. Virt-manager selects qcow2, virsh is set as described.
I'm poking around still, like reading $ man virsh
It's a new system, so I turned SELUNUX from enforced to permissible, to not avail (no one endangered by turning it off).
I'm going where you sent me and looking at everything I can, this tangent/that tangent, hoping something will shake lose.
virt-manager says my VM is running.
(I took a snapshot of my console, don't know if it'd provide you with any more information.)

Attached Thumbnails

 

As I said, a shot in the dark. Nice screenshot, by the way

Well remote diagnosis is hard here. Let me toss out a few random ideas.

Perhaps it's not a qcow2 file after all:
What were your steps? I understand you created the qcow2 file by installing from the iso, then created a new VM by importing this file. Did the original VM ever boot, right after the installation?

Use tools like guestfish, guestmount or virt-edit to inspect the file. Personally, I like guestmount:
then look around.

1 members found this post helpful.

Hi.
This may be a rookie mistake, it's been years since I was one of the SysAdmin at a start-up, and then, it was SuSE, not CentOS.

I had been running Virt-Manager logged in as root, and once I answered all the questions and said go, it didn't interact with me, just created a VM, calling it CentOS7 and couldn't find boot.

This evening, I was doing something as myself, and instead of switching user to root, instead went

$ su -s
# virt-manager

it interacted with me, built a CentOS-7 VM to my liking and boots well.
It boots command-line instead of GUI, I'll assume that's a "didn't build CentOS correctly" and not a kvm/qemu issue.

Thanks for your help(s) and patience, I learned a lot along the way.

Well, it's onto other mistakes, I've spent enough time on this one.

Following results, the only thing different was to su to root instead of being logged in as root. That couldn't be the answer but that's where the facts lead. Yesterday, I tried to duplicate, and find out exactly the gating factor. I was largely unsuccessful, I did, however, twice build a guest CentOS with a day's efforts.

I found a delightful option in virt-manager, --debug. ha ha ha.

As I said before, everything I was asked to check, checked out. With --debug, it was displaying as it was doing things, and, though not knowing all things, it mostly looks right and good. My original problem report was when I finally chose "build" it would not interact with me, like letting me create root password, etc. it just created some kind of VM, activate it, and tell me it couldn't boot. Those few times it did interact with me, giving me the chance to choose my language, etc., the normal stuff, it builds a fine VM.

I got lost in this thread about the NO BOOT, and lost the NO KEYBOARD as being the real error.

One of the --debug messages, a time or two, it's inconsistent so I can't post it here, was failure to grab keyboard, I think the message was from GTK. I've been concentrating on YUM UPDATE etc., to no avail.

I am able to clone a working VM, I've now a couple VMs, I can't build a Windows VM, though it finds the .iso and tells me its OS and VERSION, so I believe virt-manager is OK. The problem seems to be passing keyboard control from itself to the VM it creates to then build the O/S within the VM and making it bootable.

Hello:
This has long since closed, but I've continued to have the problem over the intervening years.
I had to rebuild my VM recently and again had the problem, and in the renewed search, found occasional folk with the same problem.

But I found the solution!

Unbeknownst to me the .iso on a CD/DVD is slightly different then one that's not.
Originally, I 'dd' the CD/DVD to my libvirt, as the documentation said to do, and was using that .iso-reference in virt-manager to build my new VM.

virt-manager found it OK, identified its O/S etc., built the VM, but when the VM 'booted', it was looking for the .iso on the CD/DVD drive -- virt-manager does not pass along access to the physical drive: some call this a long-standing bug, others call it a feature.

Originally, years ago, I downloaded the .iso and burned the DVD -- who knew that would cause the problem. Anyhow, now that I specify original downloaded .iso, I'm building VMs with reckless abandon.

(Much of the building a CentOS, especially when you've not done it for a while, asks you to select door#1 or door#2, without clarity why, how to choose and what are the consequences, so it took several builds before I got what I wanted. ha ha ha)

I'm only posting this for a couple of reasons -- for those that have the same problems & frustrations. And second, in case anyone's interested in explaining the .iso differences, problems, elucidations, etc. as an education for the rest of us.

Thanks loads all!!