Chapter 1. Introduction
This document provides an overview of the process for upgrading to Red Hat Enterprise Linux OpenStack Platform 7 from Red Hat Enterprise Linux OpenStack Platform 6.
If you are currently on the RHEL OpenStack Platform 5 (Icehouse) release and are looking to upgrade to RHEL OpenStack Platform 7 (Kilo) release, you need to ensure that you upgrade to the RHEL OpenStack Platform 6 (Juno) release first. The procedures to perform this upgrade are available under Upgrading from: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/6/
Red Hat only supports upgrades to Red Hat Enterprise Linux OpenStack Platform 7 on Red Hat Enterprise Linux 7. In addition, Red Hat recommends the following different methods to support this upgrade path, each of which are described better in Section 1.1, “Upgrade Methods Comparison”. Each of these methods have corresponding documentation available in the Upgrade Methods Comparison. For more details on the components, refer Components Overview available from: https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux_OpenStack_Platform/
For both the Upgrade All at Once and the Upgrading Individually scenario, this guide describes both the High Availability (HA) as well as the non-HA procedures. The major difference between the HA and non-HA procedures is that for the HA upgrade, you need to ensure your Pacemaker services are disabled and enabled appropriately.
All of the upgrade paths described below, allow you to upgrade to a working RHEL OpenStack Platform 7 (Kilo) release. It is recommended that you perform further upgrade procedures to ensure that deployment is RHEL OpenStack Platform 7 director ready using the parallel cloud migration . Parallel cloud migration for RHEL OpenStack Platform 7 deals with upgrading your existing OpenStack clouds deployed with another installer to the RHEL OpenStack Platform 7 director.
1.1. Upgrade Methods Comparison
Red Hat recommends the following methods for upgrading to Red Hat Enterprise Linux OpenStack Platform 7. The following table provides a brief description of each.
Table 1.1. Upgrade Methods
| Method | Description | Pros | Cons |
|---|---|---|---|
| All at Once |
In this method, you take down all of the OpenStack services at the same time, do the upgrade, then bring all services back up after the upgrade process is complete.
For more information, see Chapter 3, Upgrade OpenStack All at Once.
|
This upgrade process is simple. Because everything is down, no orchestration is required. Although services will be down, VM workloads can be kept running if there are no requirements to move from one version of Red Hat Enterprise Linux to another (that is, from v7.0 to v7.1).
|
All of your services will be unavailable at the same time. In a large environment, the upgrade can result in a potentially extensive downtime while you wait for database-schema upgrades to complete. Downtime can be mitigated by proper dry-runs of your upgrade procedure on a test environment as well as scheduling a specific downtime window for the upgrade.
|
| Service by Service with Live Compute Upgrade |
This method is a variation of the service-by-service upgrade, with a change in how the Compute service is upgraded. With this method, you can take advantage of Red Hat Enterprise Linux OpenStack Platform 7 features that allow to run older compute nodes in parallel with upgraded compute nodes.
For more information, see Chapter 4, Upgrade OpenStack by Updating Each Service Individually, with Live Compute.
|
This method minimizes interruptions to your Compute service, with only a few minutes for the smaller services, and a longer migration interval for the workloads moving to newly-upgraded Compute hosts. Existing workloads can run indefinitely, and you do not need to wait for a database migration.
|
Additional hardware resources may be required to bring up the Red Hat Enterprise Linux OpenStack Platform 7 (Kilo) Compute nodes.
|
For all methods:
- Ensure you have subscribed to the correct channels for this release on all hosts.
- The upgrade will involve some service interruptions.
- Running instances will not be affected by the upgrade process unless you either reboot a Compute node or explicitly shut down an instance.
- To upgrade OpenStack Networking, you will need to set the correct
libvirt_vif_driverin/etc/nova/nova.confas the old hybrid driver is now deprecated. To do so, run the following on your Compute API host:#openstack-config --set /etc/nova/nova.conf \DEFAULT libvirt_vif_driver nova.virt.libvirt.vif.LibvirtGenericVIFDriver
Warning
Red Hat does not support:
- Upgrading any Beta release of Red Hat Enterprise Linux OpenStack Platform to any supported release (for example, 6 or 7).
- Upgrading Compute Networking (nova-networking) to OpenStack Networking (neutron) in Red Hat Enterprise Linux OpenStack Platform 7. The only supported networking upgrade is between versions of OpenStack Networking (neutron) from Red Hat Enterprise Linux OpenStack Platform version 6 to version 7 .
