This doesn't seem to be the already mentioned ssh problem (which is at 1:7.4p1-10 anyway):
proxmox-ve: 5.0-15 (running kernel: 4.10.15-1-pve)
pve-manager: 5.0-23 (running version: 5.0-23/af4267bf)
pve-kernel-4.10.15-1-pve: 4.10.15-15
libpve-http-server-perl: 2.0-5
lvm2: 2.02.168-pve2
corosync: 2.4.2-pve3
libqb0: 1.0.1-1
pve-cluster: 5.0-10
qemu-server: 5.0-12
pve-firmware: 2.0-2
libpve-common-perl: 5.0-16
libpve-guest-common-perl: 2.0-11
libpve-access-control: 5.0-5
libpve-storage-perl: 5.0-12
pve-libspice-server1: 0.12.8-3
vncterm: 1.5-2
pve-docs: 5.0-8
pve-qemu-kvm: 2.9.0-2
pve-container: 2.0-14
pve-firewall: 3.0-1
pve-ha-manager: 2.0-2
ksm-control-daemon: 1.2-2
glusterfs-client: 3.8.8-1
lxc-pve: 2.0.8-3
lxcfs: 2.0.7-pve2
criu: 2.11.1-1~bpo90
novnc-pve: 0.6-4
smartmontools: 6.5+svn4324-1
zfsutils-linux: 0.6.5.9-pve16~bpo90
Jul 11 18:34:38 copying disk images
Jul 11 18:34:38 starting VM 103 on remote node 'bowie'
Jul 11 18:34:40 start remote tunnel
Jul 11 18:34:40 starting online/live migration on unix:/run/qemu-server/103.migrate
Jul 11 18:34:40 migrate_set_speed: 8589934592
Jul 11 18:34:40 migrate_set_downtime: 0.1
Jul 11 18:34:40 set migration_caps
Jul 11 18:34:40 set cachesize: 214748364
Jul 11 18:34:40 start migrate command to unix:/run/qemu-server/103.migrate
Jul 11 18:34:42 migration status error: failed
Jul 11 18:34:42 ERROR: online migrate failure - aborting
Jul 11 18:34:42 aborting phase 2 - cleanup resources
Jul 11 18:34:42 migrate_cancel
Jul 11 18:34:44 ERROR: migration finished with problems (duration 00:00:06)
TASK ERROR: migration problems
Jul 11 18:34:38 starting VM 103 on remote node 'bowie'
Jul 11 18:34:40 start remote tunnel
Jul 11 18:34:40 starting online/live migration on unix:/run/qemu-server/103.migrate
Jul 11 18:34:40 migrate_set_speed: 8589934592
Jul 11 18:34:40 migrate_set_downtime: 0.1
Jul 11 18:34:40 set migration_caps
Jul 11 18:34:40 set cachesize: 214748364
Jul 11 18:34:40 start migrate command to unix:/run/qemu-server/103.migrate
Jul 11 18:34:42 migration status error: failed
Jul 11 18:34:42 ERROR: online migrate failure - aborting
Jul 11 18:34:42 aborting phase 2 - cleanup resources
Jul 11 18:34:42 migrate_cancel
Jul 11 18:34:44 ERROR: migration finished with problems (duration 00:00:06)
TASK ERROR: migration problems
proxmox-ve: 5.0-15 (running kernel: 4.10.15-1-pve)
pve-manager: 5.0-23 (running version: 5.0-23/af4267bf)
pve-kernel-4.10.15-1-pve: 4.10.15-15
libpve-http-server-perl: 2.0-5
lvm2: 2.02.168-pve2
corosync: 2.4.2-pve3
libqb0: 1.0.1-1
pve-cluster: 5.0-10
qemu-server: 5.0-12
pve-firmware: 2.0-2
libpve-common-perl: 5.0-16
libpve-guest-common-perl: 2.0-11
libpve-access-control: 5.0-5
libpve-storage-perl: 5.0-12
pve-libspice-server1: 0.12.8-3
vncterm: 1.5-2
pve-docs: 5.0-8
pve-qemu-kvm: 2.9.0-2
pve-container: 2.0-14
pve-firewall: 3.0-1
pve-ha-manager: 2.0-2
ksm-control-daemon: 1.2-2
glusterfs-client: 3.8.8-1
lxc-pve: 2.0.8-3
lxcfs: 2.0.7-pve2
criu: 2.11.1-1~bpo90
novnc-pve: 0.6-4
smartmontools: 6.5+svn4324-1
zfsutils-linux: 0.6.5.9-pve16~bpo90