Chapter 2. OpenShift Container Storage upgrade channels and releases
In OpenShift Container Platform 4.1, Red Hat introduced the concept of channels for recommending the appropriate release versions for cluster upgrades. By controlling the pace of upgrades, these upgrade channels allow you to choose an upgrade strategy. As OpenShift Container Storage gets deployed as an Operator in OpenShift Container Platform, it follows the same strategy to control the pace of upgrades by shipping the fixes in multiple channels. Upgrade channels are tied to a minor version of OpenShift Container Storage. For example, OpenShift Container Storage 4.8 upgrade channels recommend upgrades from 4.7 to 4.8 and upgrades within 4.8. They do not recommend upgrades to 4.9 or later releases. This strategy ensures that administrators can explicitly decide to upgrade to the next minor version of OpenShift Container Storage.
Upgrade channels control only release selection and do not impact the version of the cluster that you install; the
ocs-operator decides the version of OpenShift Container Storage to be installed. Out of the box, it always installs the latest OpenShift Container Storage release maintaining the compatibility with OpenShift Container Platform. So on OpenShift Container Platform 4.8, OpenShift Container Storage 4.8 will be the latest version which can be installed.
OpenShift Container Storage upgrades are tied to the OpenShift Container Platform upgrade to ensure that compatibility and interoperability are maintained with the OpenShift Container Platform. For OpenShift Container Storage 4.8, OpenShift Container Platform 4.8 and 4.9 (when generally available) are supported. OpenShift Container Platform 4.9 is supported to maintain forward compatibility with OpenShift Container Platform. Keep the OpenShift Container Storage version the same as OpenShift Container Platform in order to get the benefit of all the features and enhancements in that release.
Due to fundamental Kubernetes design, all OpenShift Container Platform updates between minor versions must be serialized. You must update from OpenShift Container Platform 4.8 to 4.9 and then to 4.10. You cannot update from OpenShift Container Platform 4.8 to 4.10 directly. For more information, see Preparing to perform an EUS-to-EUS update of the Updating clusters guide in OpenShift Container Platform documentation.
OpenShift Container Platform 4.8 offers the following upgrade channels:
- stable-4.8 channel
- Once a new version is Generally Available, the stable channel corresponding to the minor version gets updated with the new image which can be used to upgrade. You can use the stable-4.8 channel to upgrade from OpenShift Container storage 4.7 and upgrades within 4.8.
- eus-4.y channel
- In addition to the stable channel, all even-numbered minor versions of OpenShift Container Storage offer Extended Update Support (EUS). These EUS versions extend the full and maintenance support phases for customers with Standard and Premium Subscriptions to 18 months. There is no difference between stable-4.y and eus-4.y channels, other than the fact that the EUS channels will include the release only once the next EUS release is available.