[Gluster-users] [Gluster-devel] Request for Comments: Upgrades from 3.x to 4.0+

Mon Nov 6 17:39:03 UTC 2017

Ahh OK I see, thanks

On 6 November 2017 at 00:54, Kaushal M <kshlmster at gmail.com> wrote:

> On Fri, Nov 3, 2017 at 8:50 PM, Alastair Neil <ajneil.tech at gmail.com>
> wrote:
> > Just so I am clear the upgrade process will be as follows:
> >
> > upgrade all clients to 4.0
> >
> > rolling upgrade all servers to 4.0 (with GD1)
> >
> > kill all GD1 daemons on all servers and run upgrade script (new clients
> > unable to connect at this point)
> >
> > start GD2 ( necessary or does the upgrade script do this?)
> >
> >
> > I assume that once the cluster had been migrated to GD2 the glusterd
> startup
> > script will be smart enough to start the correct version?
> >
>
> This should be the process, mostly.
>
> The upgrade script needs to GD2 running on all nodes before it can
> begin migration.
> But they don't need to have a cluster formed, the script should take
> care of forming the cluster.
>
>
> > -Thanks
> >
> >
> >
> >
> >
> > On 3 November 2017 at 04:06, Kaushal M <kshlmster at gmail.com> wrote:
> >>
> >> On Thu, Nov 2, 2017 at 7:53 PM, Darrell Budic <budic at onholyground.com>
> >> wrote:
> >> > Will the various client packages (centos in my case) be able to
> >> > automatically handle the upgrade vs new install decision, or will we
> be
> >> > required to do something manually to determine that?
> >>
> >> We should be able to do this with CentOS (and other RPM based distros)
> >> which have well split glusterfs packages currently.
> >> At this moment, I don't know exactly how much can be handled
> >> automatically, but I expect the amount of manual intervention to be
> >> minimal.
> >> The least minimum amount of manual work needed would be enabling and
> >> starting GD2 and starting the migration script.
> >>
> >> >
> >> > It’s a little unclear that things will continue without interruption
> >> > because
> >> > of the way you describe the change from GD1 to GD2, since it sounds
> like
> >> > it
> >> > stops GD1.
> >>
> >> With the described upgrade strategy, we can ensure continuous volume
> >> access to clients during the whole process (provided volumes have been
> >> setup with replication or ec).
> >>
> >> During the migration from GD1 to GD2, any existing clients still
> >> retain access, and can continue to work without interruption.
> >> This is possible because gluster keeps the management  (glusterds) and
> >> data (bricks and clients) parts separate.
> >> So it is possible to interrupt the management parts, without
> >> interrupting data access to existing clients.
> >> Clients and the server side brick processes need GlusterD to start up.
> >> But once they're running, they can run without GlusterD. GlusterD is
> >> only required again if something goes wrong.
> >> Stopping GD1 during the migration process, will not lead to any
> >> interruptions for existing clients.
> >> The brick process continue to run, and any connected clients continue
> >> to remain connected to the bricks.
> >> Any new clients which try to mount the volumes during this migration
> >> will fail, as a GlusterD will not be available (either GD1 or GD2).
> >>
> >> > Early days, obviously, but if you could clarify if that’s what
> >> > we’re used to as a rolling upgrade or how it works, that would be
> >> > appreciated.
> >>
> >> A Gluster rolling upgrade process, allows data access to volumes
> >> during the process, while upgrading the brick processes as well.
> >> Rolling upgrades with uninterrupted access requires that volumes have
> >> redundancy (replicate or ec).
> >> Rolling upgrades involves upgrading servers belonging to a redundancy
> >> set (replica set or ec set), one at a time.
> >> One at a time,
> >> - A server is picked from a redundancy set
> >> - All Gluster processes are killed on the server, glusterd, bricks and
> >> other daemons included.
> >> - Gluster is upgraded and restarted on the server
> >> - A heal is performed to heal new data onto the bricks.
> >> - Move onto next server after heal finishes.
> >>
> >> Clients maintain uninterrupted access, because a full redundancy set
> >> is never taken offline all at once.
> >>
> >> > Also clarification that we’ll be able to upgrade from 3.x
> >> > (3.1x?) to 4.0, manually or automatically?
> >>
> >> Rolling upgrades from 3.1x to 4.0 are a manual process. But I believe,
> >> gdeploy has playbooks to automate it.
> >> At the end of this you will be left with a 4.0 cluster, but still be
> >> running GD1.
> >> Upgrading from GD1 to GD2, in 4.0 will be a manual process. A script
> >> that automates this is planned only for 4.1.
> >>
> >> >
> >> >
> >> > ________________________________
> >> > From: Kaushal M <kshlmster at gmail.com>
> >> > Subject: [Gluster-users] Request for Comments: Upgrades from 3.x to
> 4.0+
> >> > Date: November 2, 2017 at 3:56:05 AM CDT
> >> > To: gluster-users at gluster.org; Gluster Devel
> >> >
> >> > We're fast approaching the time for Gluster-4.0. And we would like to
> >> > set out the expected upgrade strategy and try to polish it to be as
> >> > user friendly as possible.
> >> >
> >> > We're getting this out here now, because there was quite a bit of
> >> > concern and confusion regarding the upgrades between 3.x and 4.0+.
> >> >
> >> > ---
> >> > ## Background
> >> >
> >> > Gluster-4.0 will bring a newer management daemon, GlusterD-2.0 (GD2),
> >> > which is backwards incompatible with the GlusterD (GD1) in
> >> > GlusterFS-3.1+.  As a hybrid cluster of GD1 and GD2 cannot be
> >> > established, rolling upgrades are not possible. This meant that
> >> > upgrades from 3.x to 4.0 would require a volume downtime and possible
> >> > client downtime.
> >> >
> >> > This was a cause of concern among many during the recently concluded
> >> > Gluster Summit 2017.
> >> >
> >> > We would like to keep pains experienced by our users to a minimum, so
> >> > we are trying to develop an upgrade strategy that avoids downtime as
> >> > much as possible.
> >> >
> >> > ## (Expected) Upgrade strategy from 3.x to 4.0
> >> >
> >> > Gluster-4.0 will ship with both GD1 and GD2.
> >> > For fresh installations, only GD2 will be installed and available by
> >> > default.
> >> > For existing installations (upgrades) GD1 will be installed and run by
> >> > default. GD2 will also be installed simultaneously, but will not run
> >> > automatically.
> >> >
> >> > GD1 will allow rolling upgrades, and allow properly setup Gluster
> >> > volumes to be upgraded to 4.0 binaries, without downtime.
> >> >
> >> > Once the full pool is upgraded, and all bricks and other daemons are
> >> > running 4.0 binaries, migration to GD2 can happen.
> >> >
> >> > To migrate to GD2, all GD1 processes in the cluster need to be killed,
> >> > and GD2 started instead.
> >> > GD2 will not automatically form a cluster. A migration script will be
> >> > provided, which will form a new GD2 cluster from the existing GD1
> >> > cluster information, and migrate volume information from GD1 into GD2.
> >> >
> >> > Once migration is complete, GD2 will pick up the running brick and
> >> > other daemon processes and continue. This will only be possible if the
> >> > rolling upgrade with GD1 happened successfully and all the processes
> >> > are running with 4.0 binaries.
> >> >
> >> > During the whole migration process, the volume would still be online
> >> > for existing clients, who can still continue to work. New clients will
> >> > not be possible during this time.
> >> >
> >> > After migration, existing clients will connect back to GD2 for
> >> > updates. GD2 listens on the same port as GD1 and provides the required
> >> > SunRPC programs.
> >> >
> >> > Once migrated to GD2, rolling upgrades to newer GD2 and Gluster
> >> > versions. without volume downtime, will be possible.
> >> >
> >> > ### FAQ and additional info
> >> >
> >> > #### Both GD1 and GD2? What?
> >> >
> >> > While both GD1 and GD2 will be shipped, the GD1 shipped will
> >> > essentially be the GD1 from the last 3.x series. It will not support
> >> > any of the newer storage or management features being planned for 4.0.
> >> > All new features will only be available from GD2.
> >> >
> >> > #### How long will GD1 be shipped/maintained for?
> >> >
> >> > We plan to maintain GD1 in the 4.x series for at least a couple of
> >> > releases, at least 1 LTM release. Current plan is to maintain it till
> >> > 4.2. Beyond 4.2, users will need to first upgrade from 3.x to 4.2, and
> >> > then upgrade to newer releases.
> >> >
> >> > #### Migration script
> >> >
> >> > The GD1 to GD2 migration script and the required features in GD2 are
> >> > being planned only for 4.1. This would technically mean most users
> >> > will only be able to migrate from 3.x to 4.1. But users can still
> >> > migrate from 3.x to 4.0 with GD1 and get many bug fixes and
> >> > improvements. They would only be missing any new features. Users who
> >> > live on the edge, should be able to the migration manually in 4.0.
> >> >
> >> > ---
> >> >
> >> > Please note that the document above gives the expected upgrade
> >> > strategy, and is not final, nor complete. More details will be added
> >> > and steps will be expanded upon, as we move forward.
> >> >
> >> > To move forward, we need your participation. Please reply to this
> >> > thread with any comments you have. We will try to answer and solve any
> >> > questions or concerns. If there a good new ideas/suggestions, they
> >> > will be integrated. If you just like it as is, let us know any way.
> >> >
> >> > Thanks.
> >> >
> >> > Kaushal and Gluster Developers.
> >> > _______________________________________________
> >> > Gluster-users mailing list
> >> > Gluster-users at gluster.org
> >> > http://lists.gluster.org/mailman/listinfo/gluster-users
> >> >
> >> >
> >> _______________________________________________
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> >> Gluster-devel at gluster.org
> >> http://lists.gluster.org/mailman/listinfo/gluster-devel
> >
> >
> >
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> > Gluster-devel at gluster.org
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>
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