You can update, or upgrade, an OpenShift Container Platform cluster by using the web console.
The OpenShift Container Platform update service is the hosted service that provides over-the-air updates to both OpenShift Container Platform and Red Hat Enterprise Linux CoreOS (RHCOS). It provides a graph, or diagram that contain vertices and the edges that connect them, of component Operators. The edges in the graph show which versions you can safely update to, and the vertices are update payloads that specify the intended state of the managed cluster components.
The Cluster Version Operator (CVO) in your cluster checks with the OpenShift Container Platform update service to see the valid updates and update paths based on current component versions and information in the graph. When you request an update, the OpenShift Container Platform CVO uses the release image for that update to upgrade your cluster. The release artifacts are hosted in Quay as container images.
To allow the OpenShift Container Platform update service to provide only compatible updates, a release verification pipeline exists to drive automation. Each release artifact is verified for compatibility with supported cloud platforms and system architectures as well as other component packages. After the pipeline confirms the suitability of a release, the OpenShift Container Platform update service notifies you that it is available.
Because the update service displays all valid updates, you must not force an update to a version that the update service does not display.
During continuous update mode, two controllers run. One continuously updates the payload manifests, applies them to the cluster, and outputs the status of the controlled rollout of the Operators, whether they are available, upgrading, or failed. The second controller polls the OpenShift Container Platform update service to determine if updates are available.
Reverting your cluster to a previous version, or a rollback, is not supported. Only upgrading to a newer version is supported.
During the upgrade process, the Machine Config Operator (MCO) applies the new configuration to your cluster machines. It cordons the number of nodes that is specified by the
maxUnavailable field on the machine configuration pool and marks them as unavailable. By default, this value is set to
1. It then applies the new configuration and reboots the machine. If you use Red Hat Enterprise Linux (RHEL) machines as workers, the MCO does not update the kubelet on these machines because you must update the OpenShift API on them first. Because the specification for the new version is applied to the old kubelet, the RHEL machine cannot return to the
Ready state. You cannot complete the update until the machines are available. However, the maximum number of nodes that are unavailable is set to ensure that normal cluster operations are likely to continue with that number of machines out of service.
In OpenShift Container Platform 4.1, Red Hat introduced the concept of channels for
recommending the appropriate release versions for cluster upgrade. By controlling
the pace of upgrades, these upgrade channels allow you to choose an upgrade
strategy. Upgrade channels are tied to a minor version of
OpenShift Container Platform. For instance, OpenShift Container Platform 4.4
upgrade channels will never include an upgrade to a 4.5 release. This strategy ensures that
administrators explicitly decide to upgrade to the next minor version of
OpenShift Container Platform. Upgrade channels control only release selection and do not impact the version of the cluster that you install; the
binary file for a specific version of OpenShift Container Platform always installs that version.
OpenShift Container Platform 4.4 offers the following upgrade channels:
candidate-4.4 channel contains candidate builds for a z-stream
Release candidates contain all the features of the product but are not supported. Use release candidate versions to test feature acceptance and assist in qualifying the next version
of OpenShift Container Platform.
A release candidate is any build that is available in the candidate channel, including ones that do not contain
-rc in their names.
After a version is available in the candidate channel, it goes through more quality checks. If
it meets the quality standard, it is promoted to the
Because of this strategy, if a specific release is available in both the
candidate-4.4 channel and in the
stable-4.4 channels, it is a Red Hat supported version.
candidate-4.4 channel can include release versions from which there are no recommended updates in any channel.
You can use the
candidate-4.4 channel to upgrade from a previous minor version of
OpenShift Container Platform.
Release candidates differ from the nightly builds. Nightly builds are available for early access to features, but updating to or from nightly builds is neither recommended nor supported. Nightly builds are not available in any upgrade channel. You can reference the OpenShift Container Platform release statuses for more build information.
fast-4.4 channel is updated with new 4.4
versions as soon as Red Hat declares the given version as a general availability
release. As such, these releases are fully supported, are production quality, and have
performed well while available as a release candidate in the
channel from where they were promoted. Some time after a release appears in the
fast-4.4 channel, it is added to the
stable-4.4 channel. Releases
never appear in the
stable-4.4 channel before they appear in the
You can use the
fast-4.4 channel to upgrade from a previous minor version of
OpenShift Container Platform.
fast-4.4 channel contains releases as soon
as their errata are published, releases are added to the
after a delay. During this delay, data is collected from Red Hat SRE teams, Red Hat support services,
and pre-production and production environments that participate in connected customer program about the stability of the release.
You can use the
stable-4.4 channel to upgrade from a previous minor version of
OpenShift Container Platform.
OpenShift Container Platform maintains an upgrade recommendation service that understands the
version of OpenShift Container Platform you have installed as well as the path to take within
the channel you choose to get you to the next release. You can imagine seeing the
following in the
The service recommends only upgrades that have been tested and have no serious issues. If your cluster is on 4.4.1 and OpenShift Container Platform suggests 4.4.4, then it is safe for you to update from 4.4.1 to 4.4.4. Do not rely on consecutive patch numbers. In this example, 4.4.2 is not, and never was, available in the channel. The update service will not suggest updating to a version of OpenShift Container Platform that contains known vulnerabilities.
Update stability depends on your channel. The presence of an update recommendation in
candidate-4.4 channel does not imply that the update is supported.
It means that no serious issues have been found with the update yet, but there might
not be significant traffic through the update to suggest stability. The presence of
an update recommendation in the
channels is a declaration that the update is fully supported while it is in the
channel. While releases will never be removed from a channel, update recommendations
that exhibit serious issues will be removed from all channels. Updates initiated
after the update recommendation has been removed might not be supported.
Red Hat will eventually provide supported update paths from any supported release in the
stable-4.4 channels to the latest release in 4.4.z,
although there can be delays while safe paths away from troubled releases are
constructed and verified.
stable-4.4 channels present a choice between receiving
general availability releases as soon as they are available or allowing Red Hat to
control the rollout of those updates. If issues are detected during rollout or at a
later time, upgrades to that version might be blocked in both the
stable-4.4 channels, and a new version might be introduced that becomes the new
preferred upgrade target.
Customers can improve this process by configuring pre-production systems on the
fast-4.4 channel, configuring production systems on the
and participating in Red Hat’s connected customer program. Red
Hat uses this program to observe the impact of updates on your specific hardware and software
configurations. Future releases might improve or alter the pace at which updates move
fast-4.4 to the
If you manage the container images for your OpenShift Container Platform clusters yourself, you must consult the Red Hat errata that is associated with product releases and note any comments that impact upgrades. During upgrade, the user interface might warn you about switching between these versions, so you must ensure that you selected an appropriate version before you bypass those warnings.
Your cluster is still supported if you change from the
stable-4.4 channel to
fast-4.4 channel. Although you can switch to the
candidate-4.4 channel at any time, some releases in that channel might be unsupported release candidates.
You can switch from the
candidate-4.4 channel to the
if your current release is a general availability release. You can always
switch from the
fast-4.4 channel to the
stable-4.4 channel, although if the current release was recently promoted to
fast-4.4 there can
be a delay of up to a day for the release to be promoted to
stable-4.4. If you change to a channel that does not include your
current release, an alert displays and no updates can be recommended, but you can
safely change back to your original channel at any point.
If updates are available, you can update your cluster from the web console.
You can find information about available OpenShift Container Platform advisories and updates in the errata section of the Customer Portal.
Have access to the web console as a user with
From the web console, click Administration > Cluster Settings and review the contents of the Overview tab.
For production clusters, ensure that the CHANNEL is set to the correct channel for
the version that you want to update to,
For production clusters, you must subscribe to a stable-* or fast-* channel.
If the UPDATE STATUS is not Updates Available, you cannot upgrade your cluster.
The DESIRED VERSION indicates the cluster version that your cluster is running or is updating to.
Click Updates Available, select
a version to update to,
and click Update.
The UPDATE STATUS changes to
Updating, and you can review the progress of
the Operator upgrades on the Cluster Operators tab.