In this article we will show you how to install OpenShift in mutliple nodes using a quick install command, atomic-openshift-installer, which is powered by ansible.

Host preparation

I use under virtual machines for OpenShift nodes to deploy

Type	CPU	Mem	HDD	hostname	OS
Master	1	2 GB	20 GB	master.example.com	RHEL 7
node	1	2 GB	20 GB	node1.example.com	RHEL 7
node	1	2 GB	20 GB	node2.example.com	RHEL 7

Host Registration

Note: If you are using other OS but not RHEL, Please go to [# Install necessary packages](# Install necessary packages) to install the packages. If you can not install some of them, try to add some repos or get the rpm file.

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# subscription-manager register --username=<user_name> --password=<password>

List the available OpenShift subscriptions:

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# subscription-manager list --available --matches '*OpenShift*'

Find pool ID for an OpenShift Container Platform subscription and attach it.
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# subscription-manager attach --pool=<pool_id>

Disable all repositories and enable only the repositories required by OpenShift Container Platform 3.5

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# subscription-manager repos --disable="*"
# yum-config-manager --disable \*
# subscription-manager repos \
    --enable="rhel-7-server-rpms" \
    --enable="rhel-7-server-extras-rpms" \
    --enable="rhel-7-server-ose-3.5-rpms" \
    --enable="rhel-7-fast-datapath-rpms"

Install necessary packages

Install the following packages.

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# yum -y install wget git net-tools bind-utils iptables-services bridge-utils bash-completion kexec sos psacct
# yum update
# yum -y install atomic-openshift-utils atomic-openshift-excluder atomic-openshift-docker-excluder
# atomic-openshift-excluder unexclude

Install and configure docker

Install docker

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# yum -y install docker

Add parameter to docker configuration file

Edit /etc/sysconfig/docker file and add --insecure-registry 172.30.0.0/16 to the OPTIONS parameter.

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OPTIONS='--selinux-enabled --insecure-registry 172.30.0.0/16'

Configure Docker Storage

Here we use an additional block device for docker storage. In /etc/sysconfig/docker-storage-setup , set DEVS to the path of the disk device. Set VG to the volume group name you wish to create.

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# cat <<EOF > /etc/sysconfig/docker-storage-setup
DEVS=/dev/vdc
VG=docker-vg
EOF

Then run docker-storage-setup and check to make sure the docker-vg was created.

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# docker-storage-setup                                                                                                                                                                                                                                [5/1868]
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Checking that no-one is using this disk right now ...
OK

Disk /dev/vdc: 31207 cylinders, 16 heads, 63 sectors/track
sfdisk:  /dev/vdc: unrecognized partition table type

Old situation:
sfdisk: No partitions found

New situation:
Units: sectors of 512 bytes, counting from 0

   Device Boot    Start       End   #sectors  Id  System
/dev/vdc1          2048  31457279   31455232  8e  Linux LVM
/dev/vdc2             0         -          0   0  Empty
/dev/vdc3             0         -          0   0  Empty
/dev/vdc4             0         -          0   0  Empty
Warning: partition 1 does not start at a cylinder boundary
Warning: partition 1 does not end at a cylinder boundary
Warning: no primary partition is marked bootable (active)
This does not matter for LILO, but the DOS MBR will not boot this disk.
Successfully wrote the new partition table

Re-reading the partition table ...

If you created or changed a DOS partition, /dev/foo7, say, then use dd(1)
to zero the first 512 bytes:  dd if=/dev/zero of=/dev/foo7 bs=512 count=1
(See fdisk(8).)
  Physical volume "/dev/vdc1" successfully created
  Volume group "docker-vg" successfully created
  Rounding up size to full physical extent 16.00 MiB
  Logical volume "docker-poolmeta" created.
  Logical volume "docker-pool" created.
  WARNING: Converting logical volume docker-vg/docker-pool and docker-vg/docker-poolmeta to pool's data and metadata volumes.
  THIS WILL DESTROY CONTENT OF LOGICAL VOLUME (filesystem etc.)
  Converted docker-vg/docker-pool to thin pool.
  Logical volume "docker-pool" changed.

Enable and start docker service.

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# systemctl enable docker
# systemctl start docker
# systemctl is-active docker

Ensure Host Access

On each hosts, generate an SSH key WITHOUT a password

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# ssh-keygen

Copy the id_rsa.pub to each host:

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# for host in master.example.com \
    node1.example.com \
    node2.example.com; \
    do ssh-copy-id -i ~/.ssh/id_rsa.pub $host; \
    done

Quick Installation

Running an Interactive Installation

Start the interactive installation by running under command, and follow the on-screen instructions to install a new OpenShift Continer Platform cluster.

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$ atomic-openshift-installer install
*** Installation Summary ***

Hosts:
- master.example.com
  - OpenShift master
  - OpenShift node (Unscheduled)
  - Etcd
  - Storage
- node1.example.com
  - OpenShift node (Dedicated)
- node2.example.com
  - OpenShift node (Dedicated)

Total OpenShift masters: 1
Total OpenShift nodes: 3

NOTE: Add a total of 3 or more masters to perform an HA installation.

Gathering information from hosts...
All hosts in config are uninstalled. Proceeding with installation...

Wrote atomic-openshift-installer config: /root/.config/openshift/installer.cfg.yml
Wrote Ansible inventory: /root/.config/openshift/hosts

Ready to run installation process.

Play 1/28 (Create initial host groups for localhost)
..
Play 2/28 (Create initial host groups for all hosts)
.
Play 3/28 (Populate config host groups)
................
Play 4/28 (Ensure that all non-node hosts are accessible)
.
Play 5/28 (Initialize host facts)
................
Play 6/28 (Gather and set facts for node hosts)
...............
Play 7/28 (Verify compatible yum/subscription-manager combination)
..
Play 8/28 (Determine openshift_version to configure on first master)
............................................................................................
Play 9/28 (Set openshift_version for all hosts)
............................................................................................
Play 10/28 (Set oo_option facts)
........
Play 11/28 (Disable excluders)
..........................
Play 12/28 (Configure etcd)
................................................................................................................................................Pausing for 10 seconds
(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)
....................................................................
Play 13/28 (Configure nfs)
...............................................
Play 14/28 (Gather and set facts for master hosts)
.......................
Play 15/28 (Determine if session secrets must be generated)
..............
Play 16/28 (Generate master session secrets)
..............
Play 17/28 (Configure masters)
.............................................................................................................................................................................................................................................................................................................................................................................................................................................
Play 18/28 (Additional master configuration)
.......................................................................................................................................................................................................................
Play 19/28 (Gather and set facts for node hosts)
...............
Play 20/28 (Evaluate node groups)
..
Play 21/28 (Configure nodes)
.............................................................................................................................................................................................................................................................................................................................................
Play 22/28 (Additional node config)
.....................................................................................................................
Play 23/28 (Create persistent volumes)
............................................................................................................................................................
Play 24/28 (Create Hosted Resources)
.......................................................................................................................................................................................................Pausing for 30 seconds
(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)
................................................
Play 25/28 (Re-enable excluder if it was previously enabled)
...............
localhost                  : ok=11   changed=0    unreachable=0    failed=0   
master.example.com         : ok=606  changed=151  unreachable=0    failed=0   
node1.example.com          : ok=202  changed=39   unreachable=0    failed=0   
node2.example.com          : ok=202  changed=39   unreachable=0    failed=0   


Installation Complete: Note: Play count is only an estimate, some plays may have been skipped or dynamically added


The installation was successful!

If this is your first time installing please take a look at the Administrator
Guide for advanced options related to routing, storage, authentication, and
more:

http://docs.openshift.com/enterprise/latest/admin_guide/overview.html

Running an unattended Installation

Unattended installation allow you to run the installation with a pre-defined configuration file. The default installation configure file path is ~/.config/openshift/installer.cfg.yml. Define the configuration file and run the install command with the -u option.

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$ atomic-openshift-installer -u install

Here is a simple example of the install.cfg.yml file. For further information, please follow Defining an Installation Configuration File

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ansible_callback_facts_yaml: /root/.config/openshift/.ansible/callback_facts.yaml
ansible_inventory_path: /root/.config/openshift/hosts
ansible_log_path: /tmp/ansible.log
deployment:
  ansible_ssh_user: root
  hosts:
  - connect_to: master.example.com
    hostname: master
    ip: 10.64.221.200
    public_hostname: master
    public_ip: 10.64.221.200
    roles:
    - master
    - etcd
    - node
    - storage
  - connect_to: node1.example.com
    hostname: node1
    ip: 10.64.221.47
    node_labels: '{''region'': ''infra''}'
    public_hostname: node1
    public_ip: 10.64.221.47
    roles:
    - node
  - connect_to: node2.example.com
    hostname: node2
    ip: 10.64.221.192
    node_labels: '{''region'': ''infra''}'
    public_hostname: node2
    public_ip: 10.64.221.192
    roles:
    - node
  master_routingconfig_subdomain: ''
  openshift_master_cluster_hostname: None
  openshift_master_cluster_public_hostname: None
  proxy_exclude_hosts: ''
  proxy_http: ''
  proxy_https: ''
  roles:
    etcd: {}
    master: {}
    node: {}
    storage: {}
variant: openshift-enterprise
variant_version: '3.5'
version: v2

Also you can specify a different path of the configuration file with the -c option.

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$ atomic-openshift-installer -u -c </path/to/file> install

Verifying the installation

After the installation is completed.

Verify the master and nodes are started in Ready status. On the master host, run the following as root

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# oc get nodes

NAME                        STATUS                     AGE
master.example.com          Ready,SchedulingDisabled   165d
node1.example.com           Ready                      165d
node2.example.com           Ready                      165d

The web console use the master host name with a default port number 8443. In this test environment, you can find the web console at https://master.openshift.com:8443/console
Now that the install has been verified, run the following command on each master and node host to add the atomic-openshift packages back to the list of yum excludes on the host:
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# atomic-openshift-excluder exclude

Uninstallation

You can uninstall OpenShift Container Platform from all hosts using the follow commands

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$ atomic-openshift-installer uninstall
OpenShift will be uninstalled from the following hosts:

  * master.example.com
  * node1.example.com
  * node2.example.com

Do you want to proceed? [y/N]: y

Play 1/9 (OSEv3:children)
....
Play 2/9 (nodes)
..
Play 3/9 (masters)
..
Play 4/9 (etcd)
..
Play 5/9 (nodes)
...............................
Play 6/9 (masters)
............
Play 7/9 (etcd)
............
master.example.com         : ok=60   changed=17   unreachable=0    failed=0
node1.example.com          : ok=35   changed=8    unreachable=0    failed=0
node2.example.com          : ok=35   changed=8    unreachable=0    failed=0

If you are using a configuration file, specify the file path for the uninstallation:

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$ atomic-openshift-installer -c </path/to/file> uninstall

Host preparation#

Host Registration#

Install necessary packages#

Install and configure docker#

Install docker#

Add parameter to docker configuration file#

Configure Docker Storage#

Enable and start docker service.#

Ensure Host Access#

Quick Installation#

Running an Interactive Installation#

Running an unattended Installation#

Verifying the installation#

Uninstallation#