Unable to start several instances

Issue

• A few minutes after starting an instance, the instance will be found in a shutdown state.

• The instance logs show the following:

2019-04-22 18:38:16.999+0000: starting up libvirt version: 3.2.0, package: 14.el7_4.2 (Red Hat, Inc. <http://bugzilla.redhat.com/bugzilla>, 2017-07-18-09:40:48, x86-039.build.eng.bos.redhat.com), qemu version: 2.9.0(qemu-kvm-rhev-2.9.0-10.el7), hostname: overcloud-compute-0.localdomain
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin QEMU_AUDIO_DRV=none /usr/libexec/qemu-kvm -name guest=instance-0000033b,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-120-instance-0000033b/master-key.aes -machine pc-i440fx-rhel7.4.0,accel=kvm,usb=off,dump-guest-core=off -cpu Haswell-noTSX,vme=on,ss=on,f16c=on,rdrand=on,hypervisor=on,arat=on,tsc_adjust=on,xsaveopt=on,pdpe1gb=on,abm=on -m 20480 -realtime mlock=off -smp 20,sockets=20,cores=1,threads=1 -uuid 4d098970-f75a-4bc4-a25f-c549d9e0ba35 -smbios 'type=1,manufacturer=Red Hat,product=OpenStack Compute,version=14.0.7-11.el7ost,serial=ece3291e-67d2-4665-afb6-7e7774511eb2,uuid=4d098970-f75a-4bc4-a25f-c549d9e0ba35,family=Virtual Machine' -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-120-instance-0000033b/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=delay -no-hpet -no-shutdown -boot strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -drive file=/var/lib/nova/instances/4d098970-f75a-4bc4-a25f-c549d9e0ba35/disk,format=qcow2,if=none,id=drive-virtio-disk0,cache=none -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x5,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -drive file=/var/lib/nova/instances/4d098970-f75a-4bc4-a25f-c549d9e0ba35/disk.config,format=raw,if=none,id=drive-ide0-0-0,readonly=on,cache=none -device ide-cd,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -netdev tap,fd=27,id=hostnet0,vhost=on,vhostfd=31 -device virtio-net-pci,netdev=hostnet0,id=net0,mac=fa:16:5e:1e:04:f3,bus=pci.0,addr=0x3 -netdev tap,fd=32,id=hostnet1,vhost=on,vhostfd=47 -device virtio-net-pci,netdev=hostnet1,id=net1,mac=fa:16:5e:1e:04:f4,bus=pci.0,addr=0x4 -add-fd set=4,fd=51 -chardev file,id=charserial0,path=/dev/fdset/4,append=on -device isa-serial,chardev=charserial0,id=serial0 -chardev pty,id=charserial1 -device isa-serial,chardev=charserial1,id=serial1 -device usb-tablet,id=input0,bus=usb.0,port=1 -vnc 10.10.10.10:2 -k en-us -device cirrus-vga,id=video0,bus=pci.0,addr=0x2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -msg timestamp=on
2019-04-22T18:38:17.125212Z qemu-kvm: -chardev pty,id=charserial1: char device redirected to /dev/pts/2 (label charserial1)
2019-04-22T18:38:34.225542Z qemu-kvm: terminating on signal 15 from pid 7018 (<unknown process>)
2019-04-22 18:38:34.760+0000: shutting down, reason=shutdown