Differences between revisions 12 and 39 (spanning 27 versions)

GlusterFS

GlusterFS is a distributed filesystem. It has built in redundancy, so it is possible to run two servers which automatically replicate files between the servers. If one server goes down, the other just takes over. Once it comes up again, files are automatically replicated. Here we will use GlusterFS as a redundant network mounted file storage.

For the sport of it, we will configure 4 GlusterFS servers.

Network

The GlusterFS servers will have fixed IP-addresses. That is configured in the DHCP servers list of statically assigned IP-adresses by using the Domains MAC address.

192.168.1.40 gluster01
192.168.1.41 gluster02
192.168.1.42 gluster03
192.168.1.43 gluster04

Disk

Add hardware

To keep things separated the OS will be on one disk and the glusterfs filesystem will be on another disk. We will add a disk to the domain. This disk will be used for the glusterfs file storage.

Configure disk

Partition

Create one large partition on /dev/vdb with partition type 8e Linux LVM.

LVM

Set up a new physical volume, configure a volume group and add a volume

pvcreate /dev/vdb1
vgcreate vg2 /dev/vdb1
lvcreate --size 4G --name gluster_www vg2

Format

Create a filesystem on the volume.

mkfs.btrfs /dev/vg2/gluster_www

Mountpoint

Create the mountpoint.

mkdir /srv/www

fstab

Add the volume to /etc/fstab.

/dev/vg2/gluster_www /srv/www               btrfs   defaults        0       0

Mount

Mount the new volume.

mount /srv/www

If the mount command does not succeed, it it most likely because the fstab entry is incorrect.

Software

Mount Point

Glusterfs is not happy about using a directory which is also a mountpoint.

volume create: www: failed: The brick gluster01:/srv/www is a mount point. Please create a sub-directory under the mount point and use that as the brick directory. Or use 'force' at the end of the command if you want to override this behavior.

If for some reason the filesystem is not mounted, then glusterfs might misunderstand the situation and tell the other servers that the directory is now empty, and all files would be deleted on all servers. To avoid this a directory is created under the mount point.

mkdir /srv/www/brick

Install

Install the server.

apt-get install glusterfs-server

from gluster01 connect with the other gluster servers

gluster peer probe gluster02
gluster peer probe gluster03
gluster peer probe gluster04

check server status

gluster peer status
Number of Peers: 3

Hostname: gluster02
Uuid: 031573c2-3b1f-4946-bd78-421563249db6
State: Peer in Cluster (Connected)

Hostname: gluster03
Uuid: ff5cec1c-6d7f-4db7-8676-08deff06b4d0
State: Peer in Cluster (Connected)

Hostname: gluster04
Uuid: 65fc398a-52e9-4292-9bbb-884becfbf5d6
State: Peer in Cluster (Connected)

create the gluster volume. the force option is needed because we are creating the volume on a mountpoint.

 gluster volume create www replica 4 transport tcp gluster01:/srv/www/brick gluster02:/srv/www/brick gluster03:/srv/www/brick gluster04:/srv/www/brick

start the volume

root@gluster01:/srv/www# gluster volume start www
volume start: www: success
root@gluster01:/srv/www# gluster volume status
Status of volume: www
Gluster process                             TCP Port  RDMA Port  Online  Pid
------------------------------------------------------------------------------
Brick gluster01:/srv/www                    49152     0          Y       826  
Brick gluster02:/srv/www                    49152     0          Y       1355 
Brick gluster03:/srv/www                    49152     0          Y       1034 
Brick gluster04:/srv/www                    49152     0          Y       1135 
Self-heal Daemon on localhost               N/A       N/A        Y       846  
Self-heal Daemon on gluster02               N/A       N/A        Y       1377 
Self-heal Daemon on gluster03               N/A       N/A        Y       1054 
Self-heal Daemon on gluster04               N/A       N/A        Y       1155 
 
Task Status of Volume www
------------------------------------------------------------------------------
There are no active volume tasks

-  ⇤ ← Revision 12 as of 2017-12-19 23:59:04 → 
  Size: 1558
  Editor: Kristian Kallenberg
  Comment:
+   ← Revision 39 as of 2017-12-21 21:25:08 → ⇥
  Size: 4457
  Editor: Kristian Kallenberg
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 18:
-We will add an additional disk to the system. This disk will be used for file storage.
+=== Add hardware ===
To keep things separated the OS will be on one disk and the glusterfs filesystem will be on another disk. We will [[Domain Editing|add a disk]] to the domain. This disk will be used for the glusterfs file storage.

=== Configure disk ===

==== Partition ====
Create one large partition on `/dev/vdb` with partition type `8e Linux LVM`.

==== LVM ====
Set up a new physical volume, configure a volume group and add a volume
{{{
pvcreate /dev/vdb1
vgcreate vg2 /dev/vdb1
lvcreate --size 4G --name gluster_www vg2
}}}

==== Format ====
Create a filesystem on the volume.
{{{
mkfs.btrfs /dev/vg2/gluster_www
}}}

==== Mountpoint ====
Create the mountpoint.
{{{
mkdir /srv/www
}}}

==== fstab ====
Add the volume to `/etc/fstab`.
{{{
/dev/vg2/gluster_www /srv/www               btrfs   defaults        0       0
}}}

==== Mount ====
Mount the new volume.
{{{
mount /srv/www
}}}
If the mount command does not succeed, it it most likely because the fstab entry is incorrect.
-Line 22:
+Line 61:
+=== Mount Point ===
Glusterfs is not happy about using a directory which is also a mountpoint.

''volume create: www: failed: The brick gluster01:/srv/www is a mount point. Please create a sub-directory under the mount point and use that as the brick directory. Or use 'force' at the end of the command if you want to override this behavior.''

If for some reason the filesystem is not mounted, then glusterfs might misunderstand the situation and tell the other servers that the directory is now empty, and all files would be deleted on all servers. To avoid this a directory is created under the mount point.
{{{
mkdir /srv/www/brick
}}}

=== Install ===
Install the server.
-Line 53:
+Line 104:
-add a 32GiB harddisk for each of the servers
virsh attach-disk gluster01 --source /dev/vg2/kvm_gluster01_vdb --target vdb
+create the gluster volume. the force option is needed because we are creating the volume on a mountpoint.
{{{
 gluster volume create www replica 4 transport tcp gluster01:/srv/www/brick gluster02:/srv/www/brick gluster03:/srv/www/brick gluster04:/srv/www/brick
}}}
start the volume

{{{

root@gluster01:/srv/www# gluster volume start www
volume start: www: success
root@gluster01:/srv/www# gluster volume status
Status of volume: www
Gluster process                             TCP Port  RDMA Port  Online  Pid
------------------------------------------------------------------------------
Brick gluster01:/srv/www                    49152     0          Y       826  
Brick gluster02:/srv/www                    49152     0          Y       1355 
Brick gluster03:/srv/www                    49152     0          Y       1034 
Brick gluster04:/srv/www                    49152     0          Y       1135 
Self-heal Daemon on localhost               N/A       N/A        Y       846  
Self-heal Daemon on gluster02               N/A       N/A        Y       1377 
Self-heal Daemon on gluster03               N/A       N/A        Y       1054 
Self-heal Daemon on gluster04               N/A       N/A        Y       1155 
 
Task Status of Volume www
------------------------------------------------------------------------------
There are no active volume tasks
}}}