In order to install this version of GlusterFS we need to add the repositories:
Ref: https://download.gluster.org/pub/gluster/glusterfs/LATEST/Debian/
echo deb [arch=amd64] http://download.gluster.org/pub/gluster/glusterfs/3.12/LATEST/Debian/stretch/apt stretch main > /etc/apt/sources.list.d/gluster.list
wget -O - http://download.gluster.org/pub/gluster/glusterfs/3.12/rsa.pub | apt-key add -
apt-get update
apt-get install glusterfs-server xfsprogs

Format the dedicated partition for GlusterFS synchronized data:
eg. /dev/xvda3
mkfs.xfs -f -i size=512 /dev/xvda3
Example of result:
meta-data=/dev/xvda3 isize=512 agcount=4, agsize=655360 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1, sparse=0, rmapbt=0, reflink=0
data = bsize=4096 blocks=2621440, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560, version=2
= sectsz=512 sunit=0 blks, lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0

Regarding the configuration steps see:
https://wp.me/pKZRY-Kk
OR better:
https://gluster.readthedocs.io/en/latest/Install-Guide/Configure/