Part 1: Openstack TripleO Architecture and Step By Step Guide for installation of undercloud and overcloud nodes (compute, controller, ceph-storage)

• Discover the bare-metal servers on which the deployment of Openstack Platform has been deployed
• Serve as the deployment manager for the software to be deployed on these nodes
• Define complex network topology and configuration for the deployment
• Rollout of software updates and configurations to the deployed nodes
• Reconfigure an existing undercloud deployed environment
• Enable high availability support for the openstack nodes

Overcloud

• The overcloud is the resulting Red Hat OpenStack Platform environment created using the undercloud.
• This includes different nodes roles which you define based on the OpenStack Platform environment you aim to create.

TripleO architecture

TripleO is a friendly name for "OpenStack-On-OpenStack" and is a deployment and management tool for deployment, configuration and automation used by the undercloud. TripleO creates a production cloud known as the "overcloud" and the underlying deployment cloud known as the "undercloud".

Before being able to deploy the "overcloud", the "undercloud" needs to be deployed.

TripleO leverages several OpenStack services like Nova, Ironic, Neutron, Heat, Glance and Ceilometer to deploy the overcloud on bare-metal hardware.

• Ironic: Provisions physical hardware and leverages technologies like PXE and IPMI to present it for the deployment of the overcloud.
• Nova: Provisions the overcloud nodes like compute, controller, and Ceph storage nodes.
• Neutron: Provides the networking environment in which to deploy the overcloud.
• Glance: Provides the repository for images that are used by "ironic" for bare metal provisioning and while deploying overcloud nodes.
• Heat: Provides the wat to orchestrate the "overcloud" deployment with complex architecture
• Ceilometer: Helps collect metrics about the overcloud nodes
• Cinder: Provides the volumes needed to deploy the "overcloud" nodes
• Horizon: Provides the web user interface
• Keystone: Provides authentication for all the overcloud nodes.

My setup details
I will be hosting my overcloud and undercloud on virtual environment which will be running on a physical blade

My physical blade KVM host

DNS Server (my DNS server is running on the KVM host)

Undercloud Director Virtual Machine

Validate FQDN of the undercloud director

The director requires a fully qualified domain name for its installation and configuration process. This means you may need to set the hostname of your director’s host.

Ensure that there is a FQDN hostname set and that the $HOSTNAME environment variable matches that value. The easiest way to do this is to set the "undercloud_hostname" option in undercloud.conf before running the install. This will allow the installer to configure all of the hostname- related settings appropriately.

Alternatively the hostname settings can be configured manually, but this is strongly discouraged. The manual steps are as follows:

Since I am using DNS, I need not worry about this

An entry for the system’s FQDN hostname is also needed in /etc/hosts. For example, if the system is named myhost.mydomain, /etc/hosts should have an entry like:

Overcloud Controller

This will have single interface (eth0)

Overcloud Compute

This will have single interface (eth0)

Overcloud Ceph-Storage

This will have single interface (eth0)

Register your undercloud node

You must register your node to proper Red Hat subscription to get all the required rpms for the deployment

Look out for the repository which has openstack contents

Get the pool id of the openstack repo and attach it to your system

Next enable below list of repositories which will be needed for the overall tripleo deployment.

My network config

Installing the Director Packages

Use the following command to install the required command line tools for director installation and configuration:

Creating user for undercloud deployment

The undercloud and overcloud deployment must be done as a normal user and not the root user so we will create a "stack" user for this purpose.

Configure undercloud deployment parameters

Copy the sample undercloud.conf file to the home directory of "stack" user

Update the below variables in your undercloud.conf based on your setup. These variables will be used to setup your undercloud node.

The terminology are explained below

• local_ip : The IP address defined for the director’s Provisioning NIC. This is also the IP address the director uses for its DHCP and PXE boot services
• network_gateway : The gateway for the overcloud instances. This is the undercloud host, which forwards traffic to the External network.
• undercloud_public_vip : The IP address defined for the director’s Public API. Use an IP address on the Provisioning network that does not conflict with any other IP addresses or address ranges.
• undercloud_admin_vip : The IP address defined for the director’s Admin API. Use an IP address on the Provisioning network that does not conflict with any other IP addresses or address ranges.
• local_interface : The chosen interface for the director’s Provisioning NIC. This is also the device the director uses for its DHCP and PXE boot services. Change this value to your chosen device.
• network_cidr : The network that the director uses to manage overcloud instances. This is the Provisioning network, which the undercloud’s neutron service manages.
• masquerade_network : Defines the network that will masquerade for external access. This provides the Provisioning network with a degree of network address translation (NAT) so that it has external access through the director.
• dhcp_start; dhcp_end : The start and end of the DHCP allocation range for overcloud nodes. Ensure this range contains enough IP addresses to allocate your nodes.
• inspection_iprange : A range of IP address that the director’s introspection service uses during the PXE boot and provisioning process. Use comma-separated values to define the start and end of this range. Make sure this range contains enough IP addresses for your nodes and does not conflict with the range for dhcp_start and dhcp_end.

Deploy the undercloud

Undercloud deployment is completely automated and uses "puppet" manifest provided by TripleO. Below command will start the undercloud installation and configuration.

The configuration is performed using python script "/usr/lib/python2.7/site-packages/instack_undercloud/undercloud.py"

The undercloud installation is divided into two distinct phases:

• Instack: It deploys diskimage-builder elements locally. These elements describe the package installations or system configuration to be done on the undercloud node. All runnable scripts are located under the "install.d" directory under "/usr/share/instack-undercloud/puppet-stack-config/"
• os-refresh-config: It provides the mechanism for staging the deployment of system configuration and uses "os-apply-config" to apply the configuration. It manages the in-instance process of responding to changes in configuration parameters which helps to refresh configurations for any changes made during postdeloyment.