OpenStack Ironic, Cinder volume replication and Glance multi-store – OpenStack Charms 21.01

by Tytus Kurek on 12 February 2021

Canonical is proud to announce the availability of OpenStack Charms 21.01. This new release includes: a tech-preview version of OpenStack Ironic operators (charms), Cinder volume replication and Glance multi-store support for Charmed OpenStack.

OpenStack Ironic

The latest version of OpenStack Charms brings initial support for the OpenStack Ironic project. Ironic has been generally available on Ubuntu since the Kilo release. It was not included in the OpenStack Charms portfolio, however, resulting in limited adoption capabilities. The OpenStack Charms 21.01 release includes operators for OpenStack Ironic. Operators enable Charmed OpenStack users to deploy and operate Ironic together with other OpenStack components in a fully automated way.

Canonical will distribute Ironic in three operators (charms):

  • ironic-api – providing the Openstack Ironic bare metal API service
  • ironic-conductor – providing the OpenStack Ironic bare metal conductor service
  • neutron-api-plugin-ironic – providing the Bare metal ML2 Plugin to the OpenStack Neutron service

All three operators are considered tech-preview at this point. They are expected to reach a stable state with the OpenStack Charms 21.07 release.

In order to deploy OpenStack Ironic in a Charmed OpenStack environment, users have to add Ironic operators to the existing OpenStack model and add the necessary relations. They also have to deploy an additional OpenStack Nova compute service and configure it to use OpenStack Ironic as a driver. Since Charmed OpenStack uses operators and model-driven architecture, the entire process is simple and straightforward. Please refer to the deployment guide for the exact steps.

Charmed OpenStack model

OpenStack Ironic is an OpenStack project that enables fully automated bare metal provisioning. It uses preboot execution environment (PXE) and intelligent platform management interface (IPMI) technologies to turn bare metal machines on/off and provision them so that they can be used on-demand as virtual machines (VMs) with OpenStack Nova. Since the Ironic project is still facing some challenges, Canonical recommends using Metal-as-a-Service (MAAS) for bare metal provisioning unless it is absolutely necessary to use OpenStack Ironic.

Cinder volume replication

Another notable enhancement brought by OpenStack Charms 21.01 is the introduction of Cinder volume replication. This feature improves data durability and disaster recovery capabilities. Although Cinder is usually backed by Ceph in Charmed OpenStack deployments, the default replication mechanism does not span the data centre boundaries. This means that if the entire data centre fails, there is no way to recover Cinder volumes quickly. This new capability addresses this problem by enabling continuous replication of Cinder volumes across two Ceph clusters. As a result, an up to date replica is always available in the second cluster.

The feature leverages RADOS block device (RBD) mirroring technology for the purpose of asynchronous replication of Ceph block devices, serving as Cinder volumes. This enables the usage of the feature in geographically distributed environments, allowing the replication of Cinder volumes across different sites. Whether a particular Cinder volume is replicated or not is configurable for better granularity and is determined by the volume type.

Glance multi-store support

OpenStack Charms 21.01 also introduces multi-store support for OpenStack Glance. Services such as Nova and Cinder make extensive use of available optimisations for Ceph block. These services can create a copy-on-write clone of the image into a new volume which reduces both space usage as well as increases speed at instance launch time or volume creation time. While bare-metal services make extensive use of HTTP(s) URLs to efficiently retrieve images to load onto an image for deployment. Multi-store support enables the use of both Ceph RBD storage and OpenStack Swift compatible storage for serving images, allowing users to take advantage of the appropriate optimisations for each available service.

Get in touch

Get in touch with Canonical if you are interested in OpenStack consulting, commercial support or fully-managed service.

For more information about OpenStack Charms 21.01, please refer to the official release notes.

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