Hi Gianluca, Thanks for another great post!
Any chance you'd like to convert it to a blog/article on ovirt.org? On Fri, Dec 1, 2017 at 2:25 AM, Gianluca Cecchi <gianluca.cec...@gmail.com> wrote: > On Wed, Nov 29, 2017 at 6:49 PM, Demeter Tibor <tdeme...@itsmart.hu> wrote: >> >> Hi, >> >> Yes, I understand what do you talk about. It isn't too safe..:( >> We have terrabytes under that VM. >> I could make a downtime at most for eight hours (maybe), but meanwhile I >> have to copy 3 TB of vdisks. Firstly I need export (with a gigabit nic) to >> export domain, and back under 10gbe nic. >> I don't know how is enough this. >> >> Thanks >> >> Tibor > > > Hi Tibor, > I'm in shortage of time these days, but I have to admit your problem was so > intriguing that I couldn't resist and I decided to try and reproduce it. > All happened on my laptop with Fedora 26 (time to upgrade? not enough > time... ;-) > > So this is the test environment of all vms inside virt-manager: > > 1) Create 3.5.6 environment > > - CentOS 6.6 VM (this was the iso I had at hand...) with hostname c6engine35 > where I installed oVirt 3.5.6 as engine > - CentOS 6.6 VM with hostname c6rhv35 (sorry for the rhv in the name but > these weeks I'm also working on it so it came out quite naturally...) were I > installed the Hypervisor of 3.5.6 repo > > I created a local DC on top of a directory of the hypervisor (/ldomain) > I created a CentOS 6.6 VM in this storage domain with a 4Gb disk > > 2) Detach the local domain from DC > > HERE YOUR THEORETICAL DOWNTIME BEGINS > > To do so I powered off the test VM and created a fake further local domain > based on another directory of c6rhv35 > Then put into maintenance the local domain to be imported in 4.1 > The fake local domain becomes the master. > Detach the local domain. > > > 3) Create 4.1.7 environment (in your case it is already there..) > - CentOS 7.4 VM with hostname c7engine41 where I installed oVirt 4.1.7 as > engine > - CentOS 7.4 VM with hostname c7rhv41 were I installed the Hypervisor of > 4.1.7 repo > > I created a shared DC NFSDC with a cluster NFSCL > To speed things I exported a directory from the engine and used it to create > an NFS storage domain (DATANFS) for the 4.1 host and activated it > > 4) Shutdown 3.5 environment and start/configure the 3.5 hypervisor to export > its previously local storage domain directory > > Start c6rhv35 in single user mode > chkconfig service_name off > > for this service_name: > ebtables ip6tables iptables libvirt-guests libvirtd momd numad sanlock > supervdsmd vdsmd wdmd > > reboot > create an entry in /etc/exports > > /ldomain c7rhv41.localdomain.local(rw) > > service nfs start > > set up accordingly the /etc/hosts of the servers involved so that all know > all... > > 5) import domain in 4.1 > Select Storage -> Import domain and put > > c6rhv35.localdomain.local:/ldomain > > You will get a warning about it being already part of another DC: > https://drive.google.com/file/d/1HjFZhW6fCkasPak0jQH5k49Bdsg1NLSN/view?usp=sharing > > Approve operation and you arrive here: > https://drive.google.com/file/d/10d1ea0TbPCZhoaAf7br5IVqnvZx0LzSu/view?usp=sharing > > Activate the domain and you arrive here: > https://drive.google.com/file/d/1-4sMfVVj5WyaglPI8zhWUsdJqkVkxzAT/view?usp=sharing > > Now you can proceed importing your VMs; in my case only the testvm > Select he imported storage domain and then the "VM Import" tab; select the > VM and "Import": > > https://drive.google.com/file/d/18yjPvoHjTw6mOhUrlHJ2RpsdPph4qBxL/view?usp=sharing > > https://drive.google.com/file/d/1CrCzVUYC3vI4aQ2ly83b3uAQ3QQh1xhm/view?usp=sharing > > Note that it is an immediate operation, and not depending on the size of the > disks of the VM itself > At the end you get your VM imported; here details: > > https://drive.google.com/file/d/1W00TpIKAQ7cWUit_tLIQkm30wj5j56AN/view?usp=sharing > https://drive.google.com/file/d/1qq7sZV2vwapRRdjbi21Z43OOBM0m2NuY/view?usp=sharing > > While you import, you can then gradually start your VMs, so that your > downtime becomes partial and not total > https://drive.google.com/file/d/1kwrzSJBXISC0wBTtZIpdh3yJdA0g3G0A/view?usp=sharing > > When you have started all your imported VMs, YOUR THEORETICAL DOWNTIME ENDS > > Your VMS are now running on your old local storage, exported from your old > 3.5 host to your new 4.1 hosts via NFS > > You can now execute live storage migration of your disks one by one to the > desired 4.1 storage domain: > https://drive.google.com/file/d/1p6OOgDBbOFFGgy3uuWT-V8VnCMaxk4iP/view?usp=sharing > > and at the end of the move > https://drive.google.com/file/d/1dUuKQQxI0r4Bhz-N0TmRcsnjwQl1bwU6/view?usp=sharing > > Obviously there are many caveats in a real environment such as: > > - actual oVirt origin and target version could differ from mine and behavior > be different > - network visibility between the two oVirt environments > - layout of the logical networks of the two oVirt environments: when you > import you could need to change logical network and have conflicting MACS: > in my test scenario it was all on ovirtmgmt with the same macs range > - live storage migration of TB of disks.. not tested yet (by me at > least).... > - other things that don't come to mind right now.... > > HIH, > Gianluca > > > > > > > > > > > > > > > > > _______________________________________________ > Users mailing list > Users@ovirt.org > http://lists.ovirt.org/mailman/listinfo/users > -- Didi _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users