An exercise on installing Docker EE Engine and properly configuring Device Mapper on CentOS, which may be helpful for walking through the install and configuration of Docker EE Engine before actually doing so in production environments. This vagrant file is provided strictly for educational purposes.
https://www.vagrantup.com/downloads.html
https://www.virtualbox.org/wiki/Downloads
$ vagrant init centos/7
$ mkdir ../vagrant-disks
ee_url
ucp_password
Install vagrant-landrush plugin
$ vagrant plugin install landrush
$ vagrant plugin install vagrant-hostsupdater
$ vagrant plugin install vagrant-multiprovider-snap
$ vagrant up centos-ucp-node1 centos-ucp-node2 centos-ucp-node3 centos-ucp-node4 centos-ucp-node5
# Flush Mac's DNS cache
$ sudo killall -HUP mDNSResponder
After provisioning the node and installing Docker EE Engine it is highly recommended to configure DeviceMapper to use direct-lvm mode in production. You can read more about selecting Graph Drivers here: https://success.docker.com/KBase/An_Introduction_to_Storage_Solutions_for_Docker_CaaS#Selecting_Graph_Drivers
The best practice for configuring DeviceMapper with Docker is to provide a spare block device to create a logical volume as a thinpool for the graph driver storage. The Vagrantfile included below will create a second storage device in /dev/sdb with 20GB of space. You can verify this when you run fdisk -l you should be able to see the disks that are available to you.
[vagrant@centos-node ~]$ sudo su -
[root@centos-node ~]# fdisk -l
Disk /dev/sda: 42.9 GB, 42949672960 bytes, 83886080 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x000dc137
Device Boot Start End Blocks Id System
/dev/sda1 2048 4095 1024 83 Linux
/dev/sda2 * 4096 2101247 1048576 83 Linux
/dev/sda3 2101248 83886079 40892416 8e Linux LVM
Disk /dev/sdb: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/VolGroup00-LogVol00: 40.2 GB, 40231763968 bytes, 78577664 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/VolGroup00-LogVol01: 1610 MB, 1610612736 bytes, 3145728 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Configure Docker to use DeviceMapper as the graph storage driver: Configure Docker With DeviceMapper
Before properly configuring Docker with Device Mapper:
[vagrant@centos-node ~]$ docker info
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 0
Server Version: 17.03.1-ee-3
Storage Driver: overlay
Backing Filesystem: xfs
Supports d_type: true
Logging Driver: json-file
...
After properly configuring Docker with Device Mapper:
[vagrant@centos-node ~]$ docker info
[vagrant@centos-ucp-node2 ~]$ sudo docker info
Containers: 0
Running: 0
Paused: 0
Stopped: 0
Images: 0
Server Version: 17.03.1-ee-3
Storage Driver: devicemapper
Pool Name: docker-thinpool
Pool Blocksize: 524.3 kB
Base Device Size: 10.74 GB
Backing Filesystem: xfs
Data file:
Metadata file:
Data Space Used: 19.92 MB
Data Space Total: 20.4 GB
Data Space Available: 20.38 GB
Metadata Space Used: 61.44 kB
Metadata Space Total: 213.9 MB
Metadata Space Available: 213.8 MB
Thin Pool Minimum Free Space: 2.039 GB
Udev Sync Supported: true
Deferred Removal Enabled: true
Deferred Deletion Enabled: true
Deferred Deleted Device Count: 0
Library Version: 1.02.135-RHEL7 (2016-11-16)
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge host macvlan null overlay
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Init Binary: docker-init
containerd version: 4ab9917febca54791c5f071a9d1f404867857fcc
runc version: 54296cf40ad8143b62dbcaa1d90e520a2136ddfe
init version: 949e6fa
Security Options:
seccomp
Profile: default
Kernel Version: 3.10.0-514.2.2.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 2
Total Memory: 1.796 GiB
Name: centos-ucp-node2
ID: NC6P:NAW7:SKY2:HSXJ:HK3L:A3XZ:BGBY:D6KG:Z6YE:CECS:OU3R:265C
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
...
$ vagrant halt centos-ucp-node1 centos-ucp-node2 centos-ucp-node3 centos-ucp-node4 centos-ucp-node5
$ vagrant destroy centos-ucp-node1 centos-ucp-node2 centos-ucp-node3 centos-ucp-node4 centos-ucp-node5