[ovirt-users] upgrade hosted-engine os ( not hosts )

Thu Jun 30 19:43:20 UTC 2016

Op do 30 jun. 2016 om 21:17 schreef Yedidyah Bar David <didi at redhat.com>:

> On Thu, Jun 30, 2016 at 9:46 PM, Paul Groeneweg | Pazion <paul at pazion.nl>
> wrote:
> > Things are getting more clear to me, thanks!
> > And this whole upgrade is something I should prepare well and not try to
> do
> > in a few hours at night :)
> >
> > Resuming, there are multiple solutions:
> >
> > 1. upgrade el6 to el7
> > no go => I need to upgrade postgresql and redhat warns about upgrading
> 6.6
> > to 7 because of newer packages
> > 2. install a new HE on new Host new storage domain
> > a lot of work  => I have to turn off VMs, import storage domain into new
> > setup and reinstall hosts.
> > 3. install a new HE on new Host existing storage domain
> > possibly not without issues => I have to manually update references to
> the
> > hosted storage or better wait till there is an upgrade tool.
> > 4. (re)install HE in current VMS container.
> > => I can keep my Hosts and reference to the storage domain.
> >
> > So I guess my best bet is to go for option 4.
> >
> > The flow I am planning to follow would be:
> >
> > 1. Move to global maintenance ( keep VMs running )
> > 2. backup ( I have also a complete disk install of old hosted-engine )
> > 3. reboot with different conf, to boot from cd
> > 4. acces console and run install + import the backup in the engine vm
> > ? 5. run engine-setup to configure new install with engine restore data
> > 6. reboot hosted-engine
> > 7. Remove from global maintenance
> > 8. launch web gui and I should be able to manage all still running VMs
> > again.
> >
> > Would above be working or am I missing something and I  doubt step 5. Is
> > this needed?
>
> Yes.
>
> In a normal backup/restore flow, it's less important, although officially
> it's mandatory. But in above flow, it's not just backup/restore, but also
> upgrade from 3.6 to 4.0.
>
> In principle you can also do all of the above with 3.6, at least inside
> the engine, verify that all seems good, then upgrade to 4.0 later. See
> also:
>
> https://bugzilla.redhat.com/1332463
>
> But I do not remember reports from people trying it.
>
> Good point, I planned to first get 3.6 running on el7 and from there
upgrade hosted-engine to 4.0 ( between step 6 and 7 ). Altough this way I
keep old 3.6 files on my fresh installl...what would you advice? directly
install 4.0 on new el7 host? ( I am running 3.6.7, so above bug is probably
fixed ).

> One very important thing you did not mention: Try this on a test system,
> including rollback to your backup, after you finished everything and
> (supposedly) found out something broken. Better safe than sorry :-)
>

A test setup might provide a good practice. But requires extra spare
hosts...I do have a bare metal restore option. So I am able ( with cd boot
and console mode) to restore hosted engine within an hour to previous state
:-)

Thanks a lot for all info!

> Best,
>
> >
> > Best Regards,
> > Paul
> >
> >
> >
> > Op do 30 jun. 2016 om 14:44 schreef Simone Tiraboschi <
> stirabos at redhat.com>:
> >>
> >> On Thu, Jun 30, 2016 at 8:34 AM, Paul Groeneweg | Pazion <
> paul at pazion.nl>
> >> wrote:
> >> > Hi Yedidyah,
> >> >
> >> > Thank you for the comprehensive answers.
> >> >
> >> > I think I go for a complete reinstall ( read also OS upgrade tool is
> not
> >> > adviced on 6.6 or higher as there might be newer packages as on 7 ).
> No
> >> > doubting to re-use current VM or setup from scratch ( fresh host with
> >> > new
> >> > hosted-engine and existing storage domein ).
> >>
> >> If you are planning to redeploy hosted-engien from scratch and
> >> restoring on the new engine DB a backup of the previous one, please
> >> carefully consider this:
> >> https://bugzilla.redhat.com/show_bug.cgi?id=1240466#c21
> >>
> >> So, if you choose that path you'll have also to manually remove any
> >> reference to the previous hosted-engine from the restored DB.
> >> I'd strongly suggest you to wait for the upgrade tool to be fixed
> >> since manually doing this upgrade can be really error prone.
> >>
> >> > You explain the steps ( 1 to 6 ), but then don't talk about storage
> >> > domain
> >> > import.
> >> > Does it mean, when I reinstall the hosted-engine in the current he VM
> >> > and
> >> > restore an engine-backup ( step 5 ) I am able to start vm from Host
> and
> >> > it
> >> > is still connected to the master storage ( so no need for storage
> >> > import) ?
> >> >
> >> > Best Regards,
> >> > Paul Groeneweg
> >> >
> >> >
> >> > Op do 30 jun. 2016 om 08:00 schreef Yedidyah Bar David
> >> > <didi at redhat.com>:
> >> >>
> >> >> On Wed, Jun 29, 2016 at 10:07 PM, Paul Groeneweg | Pazion
> >> >> <paul at pazion.nl> wrote:
> >> >> >
> >> >> > I am looking for a way to get my hosted-engine running on el7 so I
> >> >> > can
> >> >> > upgrade to oVirt 4.0. Currently my hosts already run el7, but my
> >> >> > hosted-engine is still el6.
> >> >> >
> >> >> > I read
> >> >> >
> >> >> >
> >> >> >
> https://www.ovirt.org/documentation/how-to/hosted-engine-host-OS-upgrade/
> >> >> > but this is only about the hosts.
> >> >> >
> >> >> > I read https://www.ovirt.org/documentation/how-to/hosted-engine/,
> but
> >> >> > it
> >> >> > only mentions upgrade of the hosted-engine software, not the OS.
> >> >> >
> >> >> > I understood I can do a fresh hosted-engine install, and then
> import
> >> >> > my
> >> >> > storage domain to the new hosted engine, but:
> >> >> >
> >> >> > - Do I need to restore my hosted engine database? ( like described
> >> >> > here:
> >> >> >
> >> >> >
> >> >> >
> http://www.ovirt.org/develop/developer-guide/engine/migrate-to-hosted-engine/
> >> >> > )
> >> >>
> >> >> You might not have to, if you only care about the imported VMs from
> >> >> your
> >> >> storage. This will not keep other configuration, such as
> >> >> users/roles/permissions
> >> >> etc.
> >> >>
> >> >> > - Can I directly install hosted-engine 4.0 and then import the
> >> >> > storage
> >> >> > domain? Or should I install same hosted-engine version?
> >> >>
> >> >> AFAIK 4.0 engine can import 3.6 storage domains without problem.
> >> >>
> >> >> > - Do I first need another master storage domain or can I directly
> >> >> > import
> >> >> > my
> >> >> > old master storage domain?
> >> >>
> >> >> No idea. Even if you do, you can create a small empty one and later
> >> >> remove
> >> >> it.
> >> >>
> >> >> > - When importing the storage domain what is the risk it fails ( I
> >> >> > have
> >> >> > backups, but it would cost a day to restore all )
> >> >>
> >> >> No idea, but IIRC we got many successful reports and at most few
> >> >> failures
> >> >> for this.
> >> >>
> >> >> > - How long would import take? few minutes or hours? ( I want to
> keep
> >> >> > down
> >> >> > time as low as possible ).
> >> >>
> >> >> Again no idea. Perhaps do some test?
> >> >>
> >> >> >
> >> >> > Another option would be upgrade the OS ( with redhat-upgrade-tool )
> >> >> > or
> >> >> > is
> >> >> > this a path for disaster?
> >> >>
> >> >> Didn't work for us well, so we decided to not support it. If you
> decide
> >> >> to
> >> >> try,
> >> >> make sure you test carefully beforehand. From ovirt's POV:
> >> >> 1. You'll need to handle postgresql upgrade.
> >> >> 2. Right after OS upgrade, you'll still have (I think) el6 packages
> >> >> of the engine. It will hopefully be in a good-enough state for
> upgrade
> >> >> to 4.0, but we didn't test this.
> >> >> 3. Specifically, if upgrade fails, rollback will most likely not
> work,
> >> >> so you'll have to manually handle this - take a full vm backup and
> make
> >> >> sure you can restore it.
> >> >>
> >> >> >
> >> >> > I hope someone can tell me how I can smoothly upgrade my
> >> >> > hosted-engine
> >> >> > up to
> >> >> > el7 and run oVirt 4.
> >> >>
> >> >> We are working on a tool/wizard to help with this process. It used to
> >> >> work,
> >> >> but at some point it was decided that one of the actions it does is
> >> >> risky
> >> >> and was blocked, thus the tool is broken currently.
> >> >>
> >> >> You can invoke the tool by running: 'hosted-engine
> >> >> --upgrade-appliance'.
> >> >> As noted above, this is currently broken.
> >> >>
> >> >> There are several open bugs about it, e.g.:
> >> >>
> >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1319457
> >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1343425
> >> >> https://bugzilla.redhat.com/show_bug.cgi?id=1343593 (closed, this is
> >> >> what broke the tool)
> >> >>
> >> >> Basically, you can manually do what the tool is supposed to do:
> >> >> 1. Make sure state is clean and stable (no running/pending storage
> >> >> actions,
> >> >> no VMs in the middle of migration etc), all clusters are compat level
> >> >> 3.6,
> >> >> etc.
> >> >> 2. Move to global maintenance
> >> >> 3. backup the engine using engine-backup and keep the backup
> elsewhere
> >> >> 4. Reinstall engine vm with el7 and 4.0 engine (the tool will use the
> >> >> engine
> >> >> appliance, you might too but not sure how exactly).
> >> >> 5. Restore the backup and run engine-setup.
> >> >> 6. If all looks ok, leave global maintenance.
> >> >>
> >> >> If you manually keep a full backup of the engine vm before step 4,
> >> >> you might be able to restore this backup if there are problems.
> >> >> Doing this in the provided tool is currently the main blocking issue
> >> >> for it. Hopefully will be provided in 4.0.1.
> >> >>
> >> >> Best,
> >> >> --
> >> >> Didi
> >> >
> >> >
> >> > _______________________________________________
> >> > Users mailing list
> >> > Users at ovirt.org
> >> > http://lists.ovirt.org/mailman/listinfo/users
> >> >
>
>
>
> --
> Didi
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ovirt.org/pipermail/users/attachments/20160630/97558453/attachment-0001.html>