Overview

The quick installation method allows you to use an interactive CLI utility to install OpenShift across a set of hosts. The installation utility can deploy OpenShift components on targeted hosts by installing RPMs.

This installation method is provided to make the installation experience easier by interactively gathering the data needed to run on each host. The utility is a self-contained wrapper intended for usage on a Red Hat Enterprise Linux (RHEL) 7 system.

In addition to running interactive installations from scratch, the atomic-openshift-installer command can also be run or re-run using a predefined installation configuration file. This file can be used with the installation utility to:

Alternatively, you can use the advanced installation method for more complex environments.

Before You Begin

The installation utility allows you to install OpenShift master and node components on a defined set of hosts.

By default, any hosts you designate as masters during the installation process are automatically also configured as nodes so that the masters are configured as part of the OpenShift SDN. The node component on the masters, however, are marked unschedulable, which blocks pods from being scheduled on it. After the installation, you can mark them schedulable if you want.

Before installing OpenShift, you must first satisfy the prerequisites on your hosts, which includes verifying system and environment requirements and properly installing and configuring Docker. You must also be prepared to provide or validate the following information for each of your targeted hosts during the course of the installation:

  • User name on the target host that should run the Ansible-based installation (can be root or non-root)

  • Host name

  • Whether to install components for master, node, or both

  • Internal and external IP addresses

After following the instructions in the Prerequisites topic, you can continue to running an interactive or unattended installation.

Running an Interactive Installation

Ensure you have read through Before You Begin.

You can start the interactive installation by running:

$ atomic-openshift-installer install

Then follow the on-screen instructions to install a new OpenShift Enterprise cluster.

After it has finished, ensure that you back up the ~/.config/openshift/installer.cfg.yml installation configuration file that is created, as it is required if you later want to re-run the installation, add hosts to the cluster, or upgrade your cluster. Then, see What’s Next for the next steps on configuring your OpenShift cluster.

Defining an Installation Configuration File

The installation utility can use a predefined installation configuration file, which contains information about your installation, individual hosts, and cluster. When running an interactive installation, an installation configuration file based on your answers is created for you in ~/.config/openshift/installer.cfg.yml. The file is created if you are instructed to exit the installation to manually modify the configuration or when the installation completes. You can also create the configuration file manually from scratch to perform an unattended installation.

Example 1. Installation Configuration File Specification
version: v1 (1)
variant: openshift-enterprise (2)
variant_version: 3.0 (3)
ansible_ssh_user: root (4)
ansible_log_path: /tmp/ansible.log (5)
hosts: (6)
- ip: 10.0.0.1 (7)
  hostname: master-private.example.com (7)
  public_ip: 24.222.0.1 (8)
  public_hostname: master.example.com (8)
  master: true (9)
  node: true (9)
  connect_to: 24.222.0.1 (10)
- ip: 10.0.0.2
  hostname: node1-private.example.com
  public_ip: 24.222.0.2
  public_hostname: node1.example.com
  node: true
  connect_to: 10.0.0.2
- ip: 10.0.0.3
  hostname: node2-private.example.com
  public_ip: 24.222.0.3
  public_hostname: node2.example.com
  node: true
  connect_to: 10.0.0.3
1 The version of this installation configuration file.
2 The OpenShift variant to install. For OSE, set this to openshift-enterprise.
3 A valid version your selected variant. If not specified, this defaults to the newest version for the specified variant. For example: 3.0.
4 Defines which user Ansible uses to SSH in to remote systems for gathering facts and for the installation. By default, this is the root user, but you can set it to any user that has sudo privileges.
5 Defines where the Ansible logs are stored. By default, this is the /tmp/ansible.log file.
6 Defines a list of the hosts onto which you want to install the OpenShift master and node components.
7 Required. Allows the installer to connect to the system and gather facts before proceeding with the install.
8 Required for unattended installations. If these details are not specified, then this information is pulled from the facts gathered by the installation utility, and you are asked to confirm the details. If undefined for an unattended installation, the installation fails.
9 Determines the type of services that are installed. At least one of these must be set to true for the configuration file to be considered valid.
10 The IP address that Ansible attempts to connect to when installing, upgrading, or uninstalling the systems. If the configuration file was auto-generated, then this is the value you first enter for the host during that interactive install process.

Running an Unattended Installation

Ensure you have read through the Before You Begin.

Unattended installations allow you to define your hosts and cluster configuration in an installation configuration file before running the installation utility so that you do not have to go through all of the interactive installation questions and answers. It also allows you to resume an interactive installation you may have left unfinished, and quickly get back to where you left off.

To run an unattended installation, first define an installation configuration file at ~/.config/openshift/installer.cfg.yml. Then, run the installation utility with the -u flag:

$ atomic-openshift-installer -u install

By default in interactive or unattended mode, the installation utility uses the configuration file located at ~/.config/openshift/installer.cfg.yml if the file exists. If it does not exist, attempting to start an unattended installation fails. Alternatively, you can specify a different location for the configuration file using the -c option, but doing so will require you to specify the file location every time you run the installation:

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

After the unattended installation finishes, ensure that you back up the ~/.config/openshift/installer.cfg.yml file that was used, as it is required if you later want to re-run the installation, add hosts to the cluster, or upgrade your cluster. Then, see What’s Next for the next steps on configuring your OpenShift cluster.

Adding Nodes or Reinstalling the Cluster

Whether you began the process using an interactive or unattended installation, you can re-run the installation as long as you have an installation configuration file at ~/.config/openshift/installer.cfg.yml (or specify its location with the -c option).

To re-run an installation, use the install subcommand again in interactive or unattended mode:

$ atomic-openshift-installer install

The installer will detect your installed environment and allow you to either add an additional node or perform a clean install:

Gathering information from hosts...
Installed environment detected.
By default the installer only adds new nodes to an installed environment.
Do you want to (1) only add additional nodes or (2) perform a clean install?:

Choose one of the options and follow the on-screen instructions to complete your desired task.

Uninstalling OpenShift

You can uninstall OpenShift using the installation utility by running:

$ atomic-openshift-installer uninstall

What’s Next?

Now that you have a working OpenShift Enterprise instance, you can: