Docker Overlay2 with CentOS for production

The following short article runs through how to setup docker to use overlay2 with Centos for use in production

Pre-Requisites

• Add an extra drive to CentOS (this could also be freespace on the existing disk)
• Have docker installed (services stopped)

Setup

First we need to find our new disk:

fdisk -l

Once we have our new disk, we can start to create a our logical volume:

pvcreate /dev/sdb -f
vgcreate docker_vg /dev/sdb
lvcreate -n docker_xfs -l 100%FREE docker_vg

Now that we havve our logical volume, check that it doesnt have xfs on it already:

xfs_info /dev/docker_vg/docker_xfs

Now we can create our XFS and mount the new volume:

mkfs.xfs /dev/docker_vg/docker_xfs -f -n ftype=1
mkdir /var/lib/docker
mount /dev/docker_vg/docker_xfs /var/lib/docker

Add this to fstab in order to ensure it mounts on reboot vi /etc/fstab

/dev/docker_vg/docker_xfs/ /var/lib/docker xfs rw,relatime,seclabel,attr2,inode64,noquota 0 0

Now we can start our docker services

systemctl start docker

To test that this has worked, run the following, you should see that now you are using Overlay2 as the storage driver:

docker info