OK. So I reconfigured the kernel used during "host-engine --deploy", that is  3.10.0-514.el7.x86_64

I also maintained the qemu-kvm-ev-2.6.0-27.1.el7.x86_64 version

After reboot and exiting maintenance, also with this configuration the engine vm was able to start.

What I see in qemu logfile on host 

2016-12-15 09:43:41.365+0000: starting up libvirt version: 2.0.0, package: 10.el7 (CentOS BuildSystem <

http://bugs.centos.org>, 2016-11-12-02:15:12, c1bm.rdu2.centos.org), qemu version: 2.6.0 (qemu-kvm-ev-2

.6.0-27.1.el7), hostname: ovirt41.localdomain.local

LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name guest=HostedEngine,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-1-HostedEngine/master-key.aes -machine pc-i440fx-rhel7.2.0,accel=kvm,usb=off -cpu Broadwell,+rtm,+hle -m 6184 -realtime mlock=off -smp 1,maxcpus=16,sockets=16,cores=1,threads=1 -uuid 2a262cdc-9102-4061-841f-ec64333cdad2 -smbios 'type=1,manufacturer=oVirt,product=oVirt Node,version=7-2.1511.el7.centos.2.10,serial=564D3726-E55D-5C11-DC45-CA1A50480E83,uuid=2a262cdc-9102-4061-841f-ec64333cdad2' -nographic -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-1-HostedEngine/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=2016-12-15T09:43:41,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-reboot -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x3 -drive file=/var/run/vdsm/storage/3e7d4336-c2e1-4fdc-99e7-81a0e69cf3a3/286a8fda-b77d-48b8-80a9-15b63e5321a2/63bfeca6-dc92-4145-845d-e785a18de949,format=raw,if=none,id=drive-virtio-disk0,serial=286a8fda-b77d-48b8-80a9-15b63e5321a2,cache=none,werror=stop,rerror=stop,aio=threads -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive if=none,id=drive-ide0-1-0,readonly=on -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=30,id=hostnet0,vhost=on,vhostfd=32 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:16:3e:08:cc:5a,bus=pci.0,addr=0x2 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channels/2a262cdc-9102-4061-841f-ec64333cdad2.com.redhat.rhevm.vdsm,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.rhevm.vdsm -chardev socket,id=charchannel1,path=/var/lib/libvirt/qemu/channels/2a262cdc-9102-4061-841f-ec64333cdad2.org.qemu.guest_agent.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=org.qemu.guest_agent.0 -chardev socket,id=charchannel2,path=/var/lib/libvirt/qemu/channels/2a262cdc-9102-4061-841f-ec64333cdad2.org.ovirt.hosted-engine-setup.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=3,chardev=charchannel2,id=channel2,name=org.ovirt.hosted-engine-setup.0 -msg timestamp=on

Perhaps during host-deploy the engine VM is launched with other kind of options that can have caused problems?

I was also able to install a "normal" VM (CentOS 6.8 netinstall) into the infra.

During the initial "run once" phase the command executed has been

qemu      12862      1 27 11:19 ?        00:00:08 /usr/libexec/qemu-kvm -name guest=centos68,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-2-centos68/master-key.aes -machine pc-i440fx-rhel7.2.0,accel=kvm,usb=off -cpu Broadwell,+rtm,+hle -m size=2097152k,slots=16,maxmem=4294967296k -realtime mlock=off -smp 1,maxcpus=16,sockets=16,cores=1,threads=1 -numa node,nodeid=0,cpus=0,mem=2048 -uuid 5c178328-2114-49bc-9acf-e7d93e06c0a7 -smbios type=1,manufacturer=oVirt,product=oVirt Node,version=7-2.1511.el7.centos.2.10,serial=564D3726-E55D-5C11-DC45-CA1A50480E83,uuid=5c178328-2114-49bc-9acf-e7d93e06c0a7 -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-2-centos68/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=2016-12-15T10:19:40,driftfix=slew -global kvm-pit.lost_tick_policy=discard -no-hpet -no-shutdown -boot menu=on,splash-time=10000,strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device virtio-scsi-pci,id=scsi0,bus=pci.0,addr=0x4 -device virtio-serial-pci,id=virtio-serial0,max_ports=16,bus=pci.0,addr=0x5 -drive if=none,id=drive-ide0-1-0,readonly=on -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive file=/rhev/data-center/00000001-0001-0001-0001-000000000311/402dbd39-23df-486a-bc5b-d98c0679eb2d/images/1f3d7de8-f1d9-4cf3-828c-de98dc25869d/2536bf8b-6699-4b2b-97b6-6b8d6d6eb2d2,format=raw,if=none,id=drive-scsi0-0-0-0,serial=1f3d7de8-f1d9-4cf3-828c-de98dc25869d,cache=none,werror=stop,rerror=stop,aio=threads -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 -netdev tap,fd=32,id=hostnet0,vhost=on,vhostfd=34 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:1a:4a:16:01:51,bus=pci.0,addr=0x3,bootindex=2 -chardev socket,id=charchannel0,path=/var/lib/libvirt/qemu/channels/5c178328-2114-49bc-9acf-e7d93e06c0a7.com.redhat.rhevm.vdsm,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.rhevm.vdsm -chardev socket,id=charchannel1,path=/var/lib/libvirt/qemu/channels/5c178328-2114-49bc-9acf-e7d93e06c0a7.org.qemu.guest_agent.0,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=2,chardev=charchannel1,id=channel1,name=org.qemu.guest_agent.0 -chardev spicevmc,id=charchannel2,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=3,chardev=charchannel2,id=channel2,name=com.redhat.spice.0 -spice tls-port=5900,addr=192.168.150.121,x509-dir=/etc/pki/vdsm/libvirt-spice,tls-channel=default,tls-channel=main,tls-channel=display,tls-channel=inputs,tls-channel=cursor,tls-channel=playback,tls-channel=record,tls-channel=smartcard,tls-channel=usbredir,seamless-migration=on -device qxl-vga,id=video0,ram_size=67108864,vram_size=8388608,vram64_size_mb=0,vgamem_mb=16,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -msg timestamp=on

[root@ovirt41 ~]#

After shut down and normal "run" from web admin the command line has been the same as "run once", except (excluding timestamp reference and domain-XX reference)

run once

-boot menu=on,splash-time=10000,strict=on

-netdev tap,fd=32,id=hostnet0,vhost=on,vhostfd=34 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:1a:4a:16:01:51,bus=pci.0,addr=0x3,bootindex=2

run

-boot strict=on

-netdev tap,fd=32,id=hostnet0,vhost=on,vhostfd=34 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=00:1a:4a:16:01:51,bus=pci.0,addr=0x3

so quite consistent

Gianluca