Friday, August 29, 2014

CentOS : Creating An NFS-Like Standalone Storage Server With GlusterFS 3.2.x

Creating An NFS-Like Standalone Storage Server With GlusterFS 3.2.x 


This tutorial shows how to set up a standalone storage server on CentOs 6.3. Instead of NFS, I will useGlusterFS here. The client system will be able to access the storage as if it was a local filesystem. GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA.
I do not issue any guarantee that this will work for you!

1 Preliminary Note

In this tutorial I use two systems, a server and a client:
  • server1.example.com: IP address 192.168.0.100 (server)
  • server2.example.com: IP address 192.168.0.101 (client)
Both systems should be able to resolve the other system's hostname. If this cannot be done through DNS, you should edit the /etc/hosts file so that it looks as follows on both systems:
vi /etc/hosts
127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
192.168.0.100   server1.example.com     server1
192.168.0.101   server2.example.com     server2

::1         localhost localhost.localdomain localhost6 localhost6.localdomain6
(It is also possible to use IP addresses instead of hostnames in the following setup. If you prefer to use IP addresses, you don't have to care about whether the hostnames can be resolved or not.)

2 Enable Additional Repositories

server1/server2:
First we import the GPG keys for software packages:
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY*
Then we enable the EPEL6 repository on our two CentOS systems:
rpm --import https://fedoraproject.org/static/0608B895.txt
cd /tmp
wget http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-7.noarch.rpm
rpm -ivh epel-release-6-7.noarch.rpm
yum install yum-priorities
Edit /etc/yum.repos.d/epel.repo...
vi /etc/yum.repos.d/epel.repo
... and add the line priority=10 to the [epel] section:
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
priority=10
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6
[...]

3 Setting Up The GlusterFS Server

server1.example.com:
GlusterFS is available as a package for EPEL, therefore we can install it as follows:
yum install glusterfs-server
Create the system startup links for the Gluster daemon and start it:
chkconfig --levels 235 glusterd on
/etc/init.d/glusterd start
The command
glusterfsd --version
should now show the GlusterFS version that you've just installed (3.2.7 in this case):
[root@server1 ~]# glusterfsd --version
glusterfs 3.2.7 built on Jun 11 2012 13:22:28
Repository revision: git://git.gluster.com/glusterfs.git
Copyright (c) 2006-2011 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[root@server1 ~]#
If you use a firewall, ensure that TCP ports 111, 24007, 24008, 24009-(24009 + number of bricks across all volumes) are open on server1.example.com.
Next we create the share named testvol on localhost (= server1) in the /data directory (this will be created if it doesn't exist):
gluster volume create testvol server1.example.com:/data
[root@server1 ~]# gluster volume create testvol server1.example.com:/data
Creation of volume testvol has been successful. Please start the volume to access data.
[root@server1 ~]#
Start the volume:
gluster volume start testvol
You can check the status of the volume with the command

gluster volume info
[root@server1 ~]# gluster volume info
Volume Name: testvol
Type: Distribute
Status: Started
Number of Bricks: 1
Transport-type: tcp
Bricks:
Brick1: server1.example.com:/data
[root@server1 ~]#
If it tells you that the volume is started, everything is fine, otherwise just start it again.
By default, all clients can connect to the volume. If you want to grant access to client1.example.com (= 192.168.0.101) only, run:
gluster volume set testvol auth.allow 192.168.0.101
Please note that it is possible to use wildcards for the IP addresses (like 192.168.*) and that you can specify multiple IP addresses separated by comma (e.g.192.168.0.101,192.168.0.102).
The volume info should now show the updated status:
gluster volume info
[root@server1 ~]# gluster volume info
Volume Name: testvol
Type: Distribute
Status: Started
Number of Bricks: 1
Transport-type: tcp
Bricks:
Brick1: server1.example.com:/data
Options Reconfigured:
auth.allow: 192.168.0.101
[root@server1 ~]#

4 Setting Up The GlusterFS Client

server2.example.com:
On the client, we can install the GlusterFS client as follows:
yum install glusterfs-client
Then we create the following directory:
mkdir /mnt/glusterfs
That's it! Now we can mount the GlusterFS filesystem to /mnt/glusterfs with the following command:
mount.glusterfs server1.example.com:/testvol /mnt/glusterfs
You should now see the new share in the outputs of...
mount
[root@server2 ~]# mount
/dev/mapper/vg_client1-LogVol00 on / type ext4 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs on /dev/shm type tmpfs (rw)
/dev/sda1 on /boot type ext4 (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
server1.example.com:/testvol on /mnt/glusterfs type fuse.glusterfs (rw,allow_other,default_permissions,max_read=131072)
[root@server2 ~]#
... and...
df -h
[root@server2 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_client1-LogVol00
                      9.7G  1.7G  7.5G  19% /
tmpfs                 499M     0  499M   0% /dev/shm
/dev/sda1             504M   39M  440M   9% /boot
server1.example.com:/testvol
                      9.7G  1.7G  7.5G  19% /mnt/glusterfs
[root@server2 ~]#
Instead of mounting the GlusterFS share manually on the client, you could modify /etc/fstab so that the share gets mounted automatically when the client boots.
Open /etc/fstab and append the following line:
vi /etc/fstab
[...]
server1.example.com:/testvol /mnt/glusterfs glusterfs defaults,_netdev 0 0
To test if your modified /etc/fstab is working, reboot the client:
reboot
After the reboot, you should find the share in the outputs of...
df -h
... and...
mount

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