[libvirt-users] live migration and config

[Jiri Denemark]

On Thu, Sep 13, 2018 at 18:38:57 +0400, Dmitry Melekhov wrote:
> 
> 
> 13.09.2018 17:47, Jiri Denemark пишет:
> > On Thu, Sep 13, 2018 at 10:35:09 +0400, Dmitry Melekhov wrote:
> >> After some mistakes yesterday we ( me and my colleague ) think that it
> >> will be wise for libvirt to check config file existence on remote side
> > Which config file?
> >
> VM config file, namely qemu.

Do you mean the domain XML definition found in /etc/libvirt/qemu/*.xml ?

> We forgot to mount shared storage (namely gluster volume), on which we 
> have config files, twice...

If you're talking about the domain XML file, then you should never store
them on a shared storage. All XML files in /etc/libvirt are supposed to
be local to each host. Sharing them may cause changes done on one host
will not be seen by libvirtd on the other host and they can even get
lost when libvirtd on the other host decides to write its version of the
domain definition to the file.

And migration is designed so that the domain definition does not need to
be present on the destination host. In fact, even if it's present,
libvirtd will ignore it until you stop the migrated domain and start it
again.

> And tried to live migrate VM to another host, where there is no config
> file, so VM can't be started, so it died. Twice :-(

Error messages or logs would help. Otherwise we have no clue what failed
and why.

Jirka