Docker : Install Docker on Oracle Linux 7

 

Docker : Install Docker on Oracle Linux 7 (OL7)

Install Docker

Enable all the required repositories. To do this you are going to need the yum-utils package.

yum install -y yum-utils zip unzip

yum-config-manager --enable ol7_optional_latest

yum-config-manager --enable ol7_addons

yum install -y oraclelinux-developer-release-el7

yum-config-manager --enable ol7_developer

Install Docker and BTRFS.

yum install -y docker-engine btrfs-progs btrfs-progs-devel

Configure BTRFS

By default the containers are created under the "/var/lib/docker", so you really need to house this on a separate disk or in a separate partition, preferably using BTRFS as the file system.

NOTE : you can keep docker in default location or can create new mount .

I have a second LUN with a device named "/dev/sdb". I could build the file system on this disk directly, but I prefer to partition the disks with a single partition using fdisk. These responses will create a new partition using the whole of the disk ("n", "p", "return", "return", "return", "w").

# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.23.2).

Changes will remain in memory only, until you decide to write them.

Be careful before using the write command.

Device does not contain a recognized partition table

Building a new DOS disklabel with disk identifier 0x2ccc116e.

Command (m for help): n

Partition type:

   p   primary (0 primary, 0 extended, 4 free)

   e   extended

Select (default p): p

Partition number (1-4, default 1): 

First sector (2048-25165823, default 2048): 

Using default value 2048

Last sector, +sectors or +size{K,M,G} (2048-25165823, default 25165823): 

Using default value 25165823

Partition 1 of type Linux and of size 12 GiB is set

Command (m for help): w

The partition table has been altered!

Calling ioctl() to re-read partition table.

Syncing disks.

#

Make the BTRFS file system on the "sdb1" partition. The Oracle Linux 7 Configuring Docker Storage manual describes how to use the docker-storage-config utility to do this with a single command.

# docker-storage-config -s btrfs -d /dev/sdb1

Creating 'btrfs' file system on: /dev/sdb1

#

We can see the file system is added to the "/etc/fstab" file and has been mounted under "/var/lib/docker" by the utility.

# cat /etc/fstab

#

# /etc/fstab

# Created by anaconda on Tue Nov 14 11:49:55 2017

#

# Accessible filesystems, by reference, are maintained under '/dev/disk'

# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info

#

/dev/mapper/ol-root     /                       xfs     defaults        0 0

UUID=196ae589-c060-46b9-87dc-49d3ed2b01e7 /boot                   xfs     defaults        0 0

/dev/mapper/ol-swap     swap                    swap    defaults        0 0

UUID=10dbd6c1-8ae4-420e-91d8-b021f334e82b /var/lib/docker btrfs defaults 0 0 # added by docker-storage-config

#

# df -h

Filesystem           Size  Used Avail Use% Mounted on

devtmpfs             7.7G     0  7.7G   0% /dev

tmpfs                7.8G     0  7.8G   0% /dev/shm

tmpfs                7.8G   25M  7.7G   1% /run

tmpfs                7.8G     0  7.8G   0% /sys/fs/cgroup

/dev/mapper/ol-root   45G   25G   21G  55% /

/dev/sda1            497M  291M  206M  59% /boot

tmpfs                1.6G   12K  1.6G   1% /run/user/42

tmpfs                1.6G     0  1.6G   0% /run/user/0

/dev/sdb1            100G   17M   98G   1% /var/lib/docker

#

If we didn't have access to the docker-storage-config utility we could have used the following commands.

# mkfs.btrfs -f -L docker1 /dev/sdb1

# systemctl stop docker.service

# rm -Rf /var/lib/docker

# mkdir /var/lib/docker

# echo "LABEL=docker1  /var/lib/docker btrfs defaults 0 0" >> /etc/fstab

# mount /var/lib/docker

Finish Docker Setup

Enable and start the Docker service.

# systemctl enable docker.service

# systemctl start docker.service

You can get information about docker using the following commands.

# systemctl status docker.service

# docker info

# docker version

You are now ready to start using Docker!