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New in Red Hat®️ OpenStack®️ Platform 13, the fast forward upgrade feature lets you easily move between long-life releases, without the need to upgrade to each in-between release. Fast forward upgrades fully containerize Red Hat OpenStack Platform deployment to simplify and speed the upgrade process while reducing interruptions and eliminating the need for additional hardware. Today, we’ll take a look at what the fast forward upgrade process from Red Hat OpenStack Platform 10 to Red Hat OpenStack Platform 13 looks like in practice.
There are six main steps in the process:
- Cloud backup. Back up your existing cloud.
- Minor update. Update to the latest minor release.
- Undercloud upgrade. Upgrade your undercloud.
- Overcloud preparation. Prepare your overcloud.
- Overcloud upgrade. Upgrade your overcloud.
- Convergence. Converge your environment.
Step 1: Back up your existing cloud
First, you need to back up everything in your existing Red Hat OpenStack Platform 10 cloud, including your undercloud, overcloud, and any supporting services. It’s likely that you already have these procedures in place, but Red Hat also provides comprehensive Ansible playbooks to simply the fast forward process even more.
Manual backup procedures are likewise supported by Red Hat’s Customer Experience and Engagement (CEE) group.
A typical OpenStack backup process may involve the following steps:
- Notify your users.
- Purge your databases, including any unnecessary data stored by Heat or other OpenStack services. This will help to streamline the backup and upgrade process.
- Run undercloud and overcloud backups. This will preserve an initial backup of the cloud - it may take some time if you don’t have another backup to reference to this point in time.
By performing a backup before starting the upgrade, you can speed the overall upgrade process by only requiring smaller backups later on.
Step 2: Update to the latest minor release
Next, update your Red Hat OpenStack Platform environment to the latest minor release using the standard minor update processes. This step consolidates all undercloud and overcloud node reboots required for moving to Red Hat OpenStack Platform 13. This simplifies the overall upgrade, as no reboots are needed in later steps. For example, an upgrade from Red Hat OpenStack Platform 10 to the latest, fast forward-ready minor release will update Open vSwitch (OVS) to version 2.9, Red Hat Enterprise Linux to version 7.5, and Red Hat Ceph®️ Storage to version 2.5 in your overcloud. These steps do require node reboots, so you can live-migrate workloads prior rebooting nodes to avoid downtime.
Step 3: Upgrade your undercloud
In this step, you’ll upgrade Red Hat OpenStack Platform director, known as the undercloud, to the new long-life release. This requires manual rolling updates from Red Hat OpenStack Platform 10 to 11 to 12 to 13, but does not require any reboots, as they were completed in the previous minor update. The same action pattern is repeated for each release: enable the new repository, stop main OpenStack Platform services, upgrade director’s main packages, and upgrade the undercloud. Note that Red Hat OpenStack Platform director will not be able to manage the version 10 overcloud during or after these upgrades.
Step 4: Prepare your overcloud
Red Hat OpenStack Platform 13 introduces containerized OpenStack services to the long-life release cadence. This step goes through the process to create the container registry to support the deployment of these new services during the fast forward procedure.
The first part of this step is to prepare the container images to accomplish this:
- Upload Red Hat OpenStack Platform 13 container images to your cloud environment. These can be stored on the director node or on additional hardware. If you choose to store them on your director node, ensure that the node has enough space available for the images. Note that during this part, your undercloud will be unable to scale your overcloud.
Next, you’ll prepare your overcloud for features introduced in Red Hat OpenStack Platform 11 and 12, including composable networks and roles:
- Include new services in any custom roles_data files.
- Edit any custom roles_data files to add composable networks (new for Red Hat OpenStack Platform 13) to each role.
- Remove deprecated services from any custom roles_data files and update deprecated parameters in custom environment files.
If you have a Red Hat OpenStack Platform director-managed Red Hat Ceph Storage cluster or storage backends, you’ll also need to prepare your storage nodes for new, containerized configuration methods.
- Install the ceph-ansible package of playbooks in your undercloud and check that you are using the latest resources and configurations in your storage environment file.
- Update custom storage backend environment files to include new parameters and resources for composable services. This applies to NetApp, Dell EMC, and Dell EqualLogic block storage backends using cinder.
Finally, if your undercloud uses SSL/TLS for its Public API, you’ll need to allow your overcloud to access your undercloud’s OpenStack Object Storage (swift) Public API during the upgrade process.
- Add your undercloud’s certificate authority to each overcloud node using an Ansible playbook.
- Perform one last backup. This is the final opportunity for backups before starting the overcloud upgrade.
Step 5: Upgrade your overcloud
This step is the core of the fast forward upgrade procedure. Remember that director is unable to manage your overcloud until this step is completed. During this step you’ll upgrade all overcloud roles and services from version 10 to version 13 using a fully managed series of commands. Let’s take a look at the process for each role.
First, you’ll upgrade your control plane. This is performed on a single controller node, but does require your entire control plane to be down. Even so, it does not affect currently running workloads. Upgrade the chosen controller node sequentially through Red Hat OpenStack Platform releases to version 13. Once the database on the upgraded controller has been updated, containerized Red Hat OpenStack Platform 13 services can be deployed to all other controllers.
Next, you’ll upgrade your compute nodes. As with your controller nodes, only OpenStack services are upgraded—not the underlying operating system. Node reboots are not required and workloads are unaffected by the process. The upgrade process is very fast, as it adds containerized services alongside RPM-based services and then simply switches over each service. During the process, however, compute users will not be able to create new instances. Some network services may also be affected.
To get familiar with the process and ensure compatibility with your environment, we recommend starting with a single, low-risk compute node.
Storage (Red Hat Ceph Storage) nodes
Finally, you’ll upgrade your Red Hat Ceph Storage nodes. While this upgrade is slightly different than the controller and compute nodes, it is not disruptive to services and your data plane remains available throughout the procedure. Director uses the ceph-ansible installer making upgrading your storage nodes simpler. It uses a rolling upgrade process to first upgrade your bare-metal services to Ceph 3.0, and then containerizes Ceph services.
Step 6: Converge your environment
At this point, you’re almost done with the fast forward process. The final step is to converge all components in your new Red Hat OpenStack Platform 13 environment. As mentioned previously, until all overcloud components are upgraded to the same version as your Red Hat OpenStack Platform director, you have only limited overcloud management capabilities. While your workloads are unaffected, you’ll definitely want to regain full control over your environment.
This step finishes the fast forward upgrade process. You’ll update your overcloud stack within your undercloud. This ensures that your undercloud has the current view of your overcloud and resets your overcloud for ongoing operation. Finally, you’ll be able to operate your Red Hat OpenStack Platform environment as normal: add nodes, upgrade components, scale services, and manage everything from director.
Fast forward upgrades simplify the process of moving between long-life releases of Red Hat OpenStack Platform. However, upgrading from Red Hat OpenStack Platform 10 to containerized architecture of Red Hat OpenStack Platform 13 is still a significant change. As always, Red Hat is ready to help you succeed with detailed documentation, subscription support, and consulting services.
Watch the OpenStack Upgrades Strategy: The Fast Forward Upgrade video from OpenStack Summit Vancouver 2018 to learn more about the fast forward upgrade approach.
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