https://github.com/nmasse-itix/openshift-host-preparation
An Ansible Playbook that prepares hosts for an OpenShift installation
https://github.com/nmasse-itix/openshift-host-preparation
Last synced: about 2 months ago
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An Ansible Playbook that prepares hosts for an OpenShift installation
- Host: GitHub
- URL: https://github.com/nmasse-itix/openshift-host-preparation
- Owner: nmasse-itix
- License: mit
- Created: 2018-04-03T14:24:32.000Z (about 7 years ago)
- Default Branch: master
- Last Pushed: 2018-10-31T12:29:25.000Z (over 6 years ago)
- Last Synced: 2025-02-12T11:16:26.558Z (4 months ago)
- Size: 17.6 KB
- Stars: 6
- Watchers: 2
- Forks: 12
- Open Issues: 6
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# OpenShift Host Preparation - Ansible Playbook
This repository is an Ansible Playbook that prepares hosts for an OpenShift
installation.
It checks that the pre-requisites given in the OpenShift Documentation, sections [Prerequisites](https://docs.openshift.com/container-platform/latest/install_config/install/prerequisites.html)
and [Host Preparation](https://docs.openshift.com/container-platform/latest/install_config/install/host_preparation.html)
are met.
It uses the same inventory file as the `openshift-ansible` playbooks.
## Usage
If not already done, craft your inventory file as described in the
[OpenShift documentation](https://docs.openshift.com/container-platform/latest/install_config/install/advanced_install.html).
A very minimal inventory file would be:
```ini
[OSEv3]
machine1.mydomain.com
machine2.mydomain.com
...
machineX.mydomain.com
[OSEv3:vars]
ansible_user=john
openshift_master_default_subdomain=app.mydomain.com
```
The main parts of the inventory are:
- the `OSEv3` group where you can declare all the machines of your cluster
- the `ansible_user` variable that hold the username used to connect to the machines using SSH
- the `openshift_master_default_subdomain` is your Wildcard DNS as explained [here](https://docs.openshift.com/container-platform/3.9/install_config/install/prerequisites.html#wildcard-dns-prereq)
Then, assuming you saved your inventory file in `/etc/ansible/hosts`, you can run the playbook with:
```sh
ansible-playbook -i /etc/ansible/hosts prepare.yml
```
## What does this playbook
This playbook goes through the following steps:
- Make sure `net.ipv4.ip_forward` is set to `1`
- Remove any locally installed DNS server that might interfere with OpenShift
- Make sure nothing is listening on port 53
- Ensures there is no residue of a previous installation of Kubernetes
- Activate SELinux if it has been disabled
- Install basic admin tools (for a complete list, check the playbook)
- Install and enable NetworkManager
- Check if the Wildcard DNS is working
- Make sure the DNS names of the machines are consistent
- Enable the OpenShift repositories
- Install Docker
- Configure Docker for OverlayFS
- Make sure the filesystem holding `/var/lib/docker` is formatted as XFS
- Install the `openshift-ansible` package
Note: several steps require a reboot to apply the new configuration or detect
any misconfiguration, be prepared!