Openshift origin installation electricity invented

############

The next piece of infrastructure in your cluster is storage. You need storage if your app needs some form of persistence(think MySQL DB) and for other stuff, like storing your container images. OpenShift comes with a multitude of options for setting up storage for the cluster. You can either electricity physics khan academy wire it up with the de facto storage for that cloud(like gas prices under a dollar use EBS for AWS) or use a cloud agnostic solutions like GlusterFS.

We deploy 3.11 version of OpenShift, which at the time of writing this, is the latest stable release. Also, OpenShift has many offerings, like ones with paid support, online multitenant version and the upstream, bleeding edge version called Origin and recently rebranded as OKD. We will be going with the community edition, i.e. OKD. Don’t let that deter you from using OpenShift as the community edition is equally performant and robust as the other editions. Tools of the Trade

RedHat ships elaborate and well gas quality maintained Ansible scripts to create a cluster and manage it. But that’s after the fact that you have booted the infrastructure, setup the DNS, installed prerequisites and everything. I wanted this setup to be consistent and reproducible so that anyone wanting to use OpenShift could follow the same set of instructions and get the exact same results. I automated the infrastructure creation and prerequisites part as well. Enter Terraform

Terraform helps you create electricity 4th grade powerpoint the VMs, alter their DNS settings, create volumes and attach it to the VMs all using a single command. I could use Ansible to get the same thing done, but Terraform has a slight edge when compared to Ansible. It stores the previous state of the system. It takes the input as the gas variables pogil extension questions end state of the system and alters the system until the desired state is achieved. This is not doable in Ansible. I still have a few gripes around Terraform and miss Ansible templating, but it is good enough TM to get the job done.

• The inventory file for OpenShift Ansible based installation is complex. OpenShift gsa 2016 contains a lot of moving parts, which translates to lot of configuration to make the whole thing work. This is partly based on the infrastructure you choose to run your cluster on. Because Terraform creates the infrastructure gas pain in shoulder for you, it makes sense that Terraform generates the inventory for you. You can still tweak the dials, but only at the Terraform level, not in the inventory level.

• I wanted the installation to be predictable, repeatable and consistent. Hand coding the inventory is the best way to not meet all these criteria. On the other hand, if you give a fixed set of inputs to Terraform and install the cluster from the inventory file it generated for you, you get the gas prices going up same result every time you run it, anywhere you run it(Provided you are using the same version of OpenShift).

Terraform does the grunt work of creating the VMs, mapping domains, creating volumes and attaching them, and finally generating the inventory files. The first inventory file called natural gas jokes the preinstall-inventory.cfg, contains the master and compute nodes. $ ansible-playbook -u root –private-key=~/.ssh/tf -i preinstall-inventory.cfg ./pre-install/playbook.yml

Note the release-3.11 branch. The playbooks branching convention follows the cluster version closely. Also, any ansible commands going forward must be run using the Ansible version specified in this repo. I hit issues numerous times when I used a different version of Ansible other than gas law questions and answers the one specified in this repo. Let’s install Ansible recommended by this repo by creating a virtualenv. $ cd openshift-ansible

Before you set out to install the cluster, you have to ensure that the hardware and software electricity generation in california setup thus far meet the prerequisites recommended by OpenShift. This is not set on stone and we can take the liberty to tweak it as per our needs, as set in the inventory, openshift_disable_check = disk_availability,docker_storage,memory_availability,docker_image_availability