WIP: Migration log: reduce number of entries and use microtime to avoid chances of conflicts

[brainexe]

I got some very rare errors during igvm migrate when two migrations of the same source hypervisor finished at the same second with the same CPU value:

INFO: igvm.commands: Picked hv-destination.local as destination Hypervisor
[hv-destination.local] sudo: while [ ! -L '/dev/xen-data/469788_vm-name' ]; do sleep 1; done
INFO: igvm.kvm: Starting online migration of vm vm-name from hv-source.local to hv-destination.local
INFO: igvm.kvm: Waiting for migration stats to show up
INFO: igvm.kvm: Migration progress: disk 0% 0/0MiB, memory 0% 0/0MiB,
INFO: igvm.kvm: Migration progress: disk 0% 0/0MiB, memory 0% 0/0MiB,
INFO: igvm.kvm: Migration progress: disk 2% 305/17408MiB, memory 0% 0/0MiB,
...
INFO: igvm.kvm: Migration progress: disk 100% 17410/17410MiB, memory 93% 2869/3073MiB,
libvirt: Domain Config error : Requested operation is not valid: domain is not running
INFO: igvm.kvm: Awaiting migration to finish
INFO: igvm.kvm: Migration finished
INFO: igvm.transaction: Rolling back transaction
libvirt:  error : internal error: Child process (/sbin/lvchange -aln /dev/xen-data/469788_vm-name) unexpected exit status 5:   Logical volume xen-data/469788_vm-name in use.
WARNING: igvm.transaction: Rollback action "destroy storage" failed: internal error: Child process (/sbin/lvchange -aln /dev/xen-data/469788_vm-name) unexpected exit status 5:   Logical volume xen-data/469788_vm-name in use.

Disconnecting from hv-destination.local... done.
Traceback (most recent call last):
  File "/usr/bin/igvm", line 33, in <module>
    sys.exit(load_entry_point('igvm==2.2.0', 'console_scripts', 'igvm')())
  File "/usr/lib/python3/dist-packages/igvm/cli.py", line 496, in main
    args.pop('func')(**args)
  File "/usr/lib/python3/dist-packages/igvm/host.py", line 25, in decorator
    return fn(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/igvm/commands.py", line 531, in vm_migrate
    previous_hypervisor.log_migration(_vm, '-')
  File "/usr/lib/python3/dist-packages/igvm/hypervisor.py", line 1157, in log_migration
    self.dataset_obj.commit()
  File "/usr/lib/python3/dist-packages/adminapi/dataset.py", line 488, in commit
    _handle_exception(result)
  File "/usr/lib/python3/dist-packages/adminapi/dataset.py", line 574, in _handle_exception
    raise exception_class(result['message'])
adminapi.exceptions.DatasetError: {'__all__': ['Server string attribute with this Server, Attribute and Value already exists.']}

Note:

• adapt the regexp for the SA attribute to something like \A([0-9]{10}|\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}.\d+)\s[-|+][0-9]{1,3}\Z
• link needed innogames/serveradmin changes

[TuxPowered42]

Shouldn't this test timestamp be updated to the new format too, in case we ever restrict in Serveradmin?