[Gluster-users] Upgrade Gluster 3.7 to 3.12 and add 3rd replica [howto/help]

[Diego Remolina]

Procedure looks good.

Remember to back up Gluster config files before update:

/etc/glusterfs
/var/lib/glusterd

If you are *not* on the latest 3.7.x, you are unlikely to be able to go
back to it because PPA only keeps the latest version of each major branch,
so keep that in mind. With Ubuntu, every time you update, make sure to
download and keep a manual copy of the .Deb files. Otherwise you will have
to compile the packages yourself in the event you wanted to go back.

Might need before adding 3rd replica:
gluster peer probe node3

When you add the 3rd replica, it should start healing, and there may be an
issue there if the VMs are running. Your plan to not have VMs up is good
here. Are you using sharding? If you are not sharding, I/O in running VMs
may be stopped for too long while a large image is healed. If you were
already using sharding you should be able to add the 3rd replica when VMs
are running without much issue.

Once healing is completed and if you are satisfied with 3.12, then remember
to bump op version of Gluster.

Diego


On Sep 20, 2017 19:32, "Martin Toth" <snowmailer at gmail.com> wrote:

Hello all fellow GlusterFriends,

I would like you to comment / correct my upgrade procedure steps on replica
2 volume of 3.7.x gluster.
Than I would like to change replica 2 to replica 3 in order to correct
quorum issue that Infrastructure currently has.

*Infrastructure setup:*
- all clients running on same nodes as servers (FUSE mounts)
- under gluster there is ZFS pool running as raidz2 with SSD ZLOG/ZIL cache
- all two hypervisor running as GlusterFS nodes and also Qemu compute nodes
(Ubuntu 16.04 LTS)
- we are running Qemu VMs that accesses VMs disks via gfapi (Opennebula)
- we currently run : 1x2 , Type: Replicate volume

*Current Versions :*
glusterfs-* [package] 3.7.6-1ubuntu1
qemu-* [package] 2.5+dfsg-5ubuntu10.2glusterfs3.7.14xenial1

*What we need : (New versions)*
- upgrade GlusterFS to 3.12 LTM version (Ubuntu 16.06 LTS packages are EOL
- see https://www.gluster.org/community/release-schedule/)
- I want to use https://launchpad.net/~gluster/+archive/ubuntu/
glusterfs-3.12 as package repository for 3.12
- upgrade Qemu (with build-in support for libgfapi) -
https://launchpad.net/~monotek/+archive/ubuntu/qemu-glusterfs-3.12
- (sadly Ubuntu has packages build without libgfapi support)
- add third node to replica setup of volume (this is probably most
dangerous operation)

*Backup Phase*
- backup "NFS storage” - raw DATA that runs on VMs
- stop all running VMs
- backup all running VMs (Qcow2 images) outside of gluster

*Upgrading Gluster Phase*
- killall glusterfs glusterfsd glusterd (on every server)
(this should stop all gluster services - server and client as it runs on
same nodes)
- install new Gluster Server and Client packages from repository mentioned
upper (on every server)
- install new Monotek's qemu glusterfs package with gfapi enabled support
(on every server)
- /etc/init.d/glusterfs-server start (on every server)
- /etc/init.d/glusterfs-server status - verify that all runs ok (on every
server)
- check :
- gluster volume info
- gluster volume status
- check gluster FUSE clients, if mounts working as expected
- test if various VMs are able tu boot and run as expected (if libgfapi
works in Qemu)
- reboot all nodes - do system upgrade of packages
- test and check again

*Adding third node to replica 2 setup (replica 2 => replica 3)*
(volumes will be mounted and up after upgrade and we tested VMs are able to
be served with libgfapi = upgrade of gluster sucessfuly completed)
(next we extend replica 2 to replica 3 while volumes are mounted but no
data is touched = no running VMs, only glusterfs servers and clients on
nodes)
- issue command : gluster volume add-brick volume replica 3
node3.san:/tank/gluster/brick1 (on new single node - node3)
so we change :
Bricks:
Brick1: node1.san:/tank/gluster/brick1
Brick2: node2.san:/tank/gluster/brick1
to :
Bricks:
Brick1: node1.san:/tank/gluster/brick1
Brick2: node2.san:/tank/gluster/brick1
Brick3: node3.san:/tank/gluster/brick1
- check gluster status
- (is rebalance / heal required here ?)
- start all VMs and start celebration :)

*My Questions*
- is heal and rebalance necessary in order to upgrade replica 2 to replica
3 ?
- is this upgrade procedure OK ? What more/else should I do in order to do
this upgrade correctly ?

Many thanks to all for support. Hope my little preparation howto will help
others to solve same situation.

Best Regards,
Martin

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