Designate and the Rackspace Technology OpenStack Private Cloud


OpenStackĀ® Designate allows the Rackspace Technology OpenStack Private Cloud users to use Domain Name Server (DNS) services in their environment.

Overview

The Designate ReST API provides a simple, scalable, and flexible way to program and manage DNS.

Openstack Designate provides a fully manage cloud-native solution for DNS as a Service (DNSaaS). This multi-tenant ReST API provides DNS services to end users while integrating fully with other OpenStack services. The benefits of Designate include the following ones:

  • Standardizes DNS services in OpenStack
  • Is an open-source project that avoids vendor lock
  • Offers ReST API management of records and zones
  • Is multi-tenanted to allow hosting of multiple projects and keep corresponding resources secure
  • Simplifies the DNS backend to a single point whereby users can avoid conflict within their projects and tenants
  • Enables self-service through sub- and super-DNS names
  • Reduces deployment times for resources
  • Is integral to dynamic workloads and deployments such as KubernetesĀ®

Rackspace Private Cloud including Designate

Rackspace Technology offers OpenStack Private Cloud with two products, RPC-O (based on OpenStack source code) and RPC-R (based on RedHatĀ® OSP version 13). With RPC-O (OpenStack Stein and Train releases) and RPC-R (Queens release), Rackspace is executing several important architecture changes to bring both products' architecture and capabilities closer together while improving the service with the addition of the following components:

  • Operating system upgrade
  • Shared-storage requirement
  • Bare metal provisioning (Ironic)
  • Octavia (Software load balancing)
  • DNS as Service (Designate)
  • Neutron open vSwitch plugin
  • HAProxyĀ® API load balancing

Rackspace previously made some of these capabilities available in limited availability (LA) capacity with the Rackspace managed Kubernetes service. We now extend these for general availability.

The architecture of a Rackspace managed cloud remains largely the same with minor changes, which ensures that you can migrate existing environments over time to the new design.

The following sections explore the new components.

Operating system upgrade (RPC-O)

The operating system requirement has been updated to the UbuntuĀ® 18.04 LTS Server release to accommodate the latest DellĀ® and HPĀ® server platforms and OpenStack requirements.

Rackspace Technology fully manages this layer transparently for customers, including providing first-time automated operating system package updates.

Shared storage requirement

The discovery of the CPU vulnerabilities, Spectre and Meltdown, has led to more frequent firmware, hardware-related changes, and host maintenance patches that require downtime. To eliminate workload impact during hardware maintenance, we require that all new RPC-O environments use shared storage for image and guest block storage. With shared storage, you can move virtual machines (guests) to other hosts almost instantly and eliminate any impact to compute hosts during maintenance. Consequently, the compute hosts are largely diskless. They use only local storage for the operating system and, if required, ephemeral storage. The concentration of disk space also reduces over-provisioning.

Bare metal provisioning (Ironic)

We now package Ironic, the OpenStack native, bare metal service, into every new deployment, allowing you to install the operating system image in an OpenStack-native way, with the compute (nova) API. Using the nova API enables you to reuse automation and features during host initialization, such as automated IP provisioning or user-data for scripting. You can also retain project-based resource control (quotas).

Octavia (Software load balancing)

Octavia is the reference implementation for load balancing. Load balancing distributes TCP/UDP protocol-based requests among multiple servers and makes the service scalable by allowing multiple servers to be behind one IP or web address. It also makes the system fault-tolerant by removing faulty servers from rotation until they are healthy again. Octavia achieves high availability load balancing through active-passive VM pairs and offers the following benefits:

  • Built-in active/passive high availability
  • Support for multiple listeners and pools
  • Support for L7 load balancing
  • Session persistence
  • Support for HTTP/TCP based health monitoring
  • Granular quota management
  • Support for HTTP header insertion

DNS as Service (Designate)

Designate provides a fully managed cloud-native solution for DNSaaS. This multi-tenant ReST API provides DNS services to end users while integrating fully with other OpenStack services.

The API enables you to standardize DNS services with bind as a pre-configured DNS backend system to manage DNS records and zones.

Designate also supports multiple record types per entry. Integration with other orchestration platforms, such as TerraformĀ®, exists and further enables you to achieve your automation requirements.

Neutron open vSwitch plugin (RPC-O)

The software-defined networking has up to this point been implemented with the Neutron API and Linux Bridge Agent plugin. The OpenStack community has been shifting to open vSwitch as a plugin for a long time and has provided many new features not available in the Linux Bridge plugin such as the following:

  • Redundant routers
  • Flow-based and optional hardware-accelerated routing
  • Additional support for tunnel protocols (beyond VXLAN)
  • Future integration into another software-defined networking (SDN) controller

HAProxy API load balancing

We no longer use an F5 load balancer to balance the OpenStack API. Instead, we replaced the load balancer with fully managed and automated provisioning around HAProxy. This replacement reduces the overall cost and administration effort to keep the API endpoints up to date across OpenStack and other version upgrades.

These new services follow a common goal to ensure that customers of RPC-O can further automate their processes while allowing other Rackspace products and teams to benefit from additional automation.

Also, Rackspace managed Kubernetes uses the listed services to automate the Kubernetes node management and installation. We integrate Designate and Octavia to expose cluster names and load-balanced services.

Conclusion

Rackspace Technology is pleased to offer OpenStackĀ® Designate to our RPC-O users to improve their DNS operations.

Learn more about the Rackspace OpenStack Private Cloud.

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David Krawczynski

Finding a balance for family, old cars, and IT while living by my mantra that ‘luck is equal parts strength and spirit!’

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