From 1e227a299b7ba379189b1dea08130e11faf6ac29 Mon Sep 17 00:00:00 2001 From: Schemen Date: Tue, 12 May 2026 14:33:07 +0200 Subject: [PATCH 1/4] Add release notes summary for OCP 4.21 --- .../ROOT/pages/references/release_notes.adoc | 80 ++++++------------- 1 file changed, 25 insertions(+), 55 deletions(-) diff --git a/docs/modules/ROOT/pages/references/release_notes.adoc b/docs/modules/ROOT/pages/references/release_notes.adoc index 500b28cf..cfecda33 100644 --- a/docs/modules/ROOT/pages/references/release_notes.adoc +++ b/docs/modules/ROOT/pages/references/release_notes.adoc @@ -2,6 +2,31 @@ TIP: This page lists notable changes in OpenShift releases which we find important. Reading release notes for you as a service. +== OpenShift 4.21 + +OpenShift version 4.21 is available since 2025-11-11. +This version is based on Kubernetes 1.34 and CRI-O 1.34. +The RHCOS image still uses RHEL 9.6 packages. +Find the release notes in the upstream documentation at https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html/release_notes/ocp-4-21-release-notes[OpenShift Container Platform 4.21 release notes]. +The https://www.redhat.com/en/blog/achieve-more-red-hat-openshift-421[Achieve more with Red Hat OpenShift 4.21] blog post is also a valuable resource. + +OpenShift Autoscaling gains new capabilities:: +OpenShift 4.21 improves autoscaling. The Cluster Resource Override Operator, Cluster Autoscaler, Vertical Pod Autoscaler, and Horizontal Pod Autoscaler now include network policies that restrict Operator and operand pod traffic to explicitly allowed communication only. The Vertical Pod Autoscaler can also use `InPlaceOrRecreate` mode to apply resource recommendations without recreating pods where possible, falling back to pod recreation when needed. +In addition, the Cluster Autoscaler can now be configured to cordon nodes before draining and removing them, giving administrators safer control over scale-down operations. + +Linux PSI monitoring is now available:: +Linux Pressure Stall Information is a kernel feature that measures how much time tasks spend stalled because they cannot get CPU, memory, or I/O when they need it. This will be helpful to detect clusters at risk of overload, especially in shared environments. + +The default `openshift` cluster image policy is now generally available:: +Default `openshift` cluster image policy is now GA and enabled by default. Clusters upgrading from OCP 4.20 or earlier that already have a custom `ClusterImagePolicy` named `openshift` will be marked `Upgradeable=False`. Rename or recreate the custom policy under a different name, then remove the old openshift policy before upgrading. https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/nodes/#nodes-sigstore-using[You can find more information here.] + + +End of support for vSphere 7:: +Broadcom has ended general support for VMware vSphere 7 and VMware Cloud Foundation (VCF) 4. If your existing OpenShift Container Platform cluster is running on either of these platforms, you must plan to migrate or upgrade your VMware infrastructure to a supported version. + + + + == OpenShift 4.20 OpenShift version 4.20 is available since 2025-11-11. @@ -59,58 +84,3 @@ The following APIs are no longer available in Kubernetes 1.32 and need to be mig * `ValidatingWebhookConfiguration` needs to be migrated from `admissionregistration.k8s.io/v1beta1` to `admissionregistration.k8s.io/v1`. + For more information, see https://docs.redhat.com/en/documentation/openshift_container_platform/4.20/html/release_notes/ocp-4-20-release-notes#ocp-4-20-removed-kube-apis_release-notes[APIs removed from Kubernetes 1.33]. - -== OpenShift 4.19 - -OpenShift version 4.19 is available since 2025-06-17. -This version is based on Kubernetes 1.32 and CRI-O 1.32. -The RHCOS image uses RHEL 9.6 packages. -Find the release notes in the upstream documentation at https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html/release_notes/ocp-4-19-release-notes[OpenShift Container Platform 4.19 release notes]. -The https://www.redhat.com/en/blog/red-hat-openshift-419-accelerates-virtualization-and-enterprise-ai-innovation[Red Hat unveils OpenShift 4.19] blog post is also a valuable resource. - -Routes with externally managed certificates are becoming Generally Available:: -With this release, OpenShift Container Platform routes can be configured with third-party certificate management solutions, utilizing the `.spec.tls.externalCertificate` field in the route API. -In this way, an externally managed TLS certificate can be referenced through secrets. -+ -For more information, see https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/ingress_and_load_balancing/index#nw-ingress-route-secret-load-external-cert_secured-routes[Creating a route with externally managed certificate]. - -Gateway API support for configuring cluster ingress traffic is becoming Generally Available:: -With this release, ingress cluster traffic can be managed using Gateway API resources. -Gateway API provides a robust networking solution within the transport layer, L4, and the application layer, L7, for OpenShift Container Platform clusters using a standardized open source ecosystem. -+ -For further information, see https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/ingress_and_load_balancing/#ingress-gateway-api[Gateway API with OpenShift Container Platform networking]. - -The Control Plane now supports TLS 1.3 and the Modern TLS security profile:: -For further information see https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/security_and_compliance/#tls-profiles-kubernetes-configuring_tls-security-profiles[Configuring the TLS security profile for the control plane]. - -Customization options for control plane machine names:: -This release enables specifying a prefix for machine names in the control plane machine set by setting `spec.machineNamePrefix` in the `ControlPlaneMachineSet` resource. -+ -For further information see https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/machine_management/#cpmso-config-prefix_cpmso-configuration[Adding a custom prefix to control plane machine names]. - -New CLI command to show PVC usage:: - -With 4.19, the `oc` CLI supports a new admin command to see PVC usage: `oc adm top pvc` - -Major version upgrade for Prometheus:: -In this release, Prometheus is upgraded from v2 to v3. -This incurs some breaking changes that may affect user-managed configuration. -+ -* The `le` and `quantile` labels for classic histograms and summaries are now normalized during ingestion. -+ -For instance, `le="10"` is ingested as `le="10.0"` - as a result, queries that reference these labels as integers may no longer work as intended. -* Configurations that send alerts to additional Alertmanager instances through `additionalAlertmanagerConfigs` through the Alertmanager v1 API are no longer supported. - -cgroup v1 is removed:: - -With 4.19, support for the deprecated cgroup v1 mode is dropped entirely. - -Removal of deprecated APIs in Kubernetes 1.32:: - -The following APIs are no longer available in Kubernetes 1.32 and need to be migrated: -* `FlowSchema` needs to be migrated from `flowcontrol.apiserver.k8s.io/v1beta3` to `flowcontrol.apiserver.k8s.io/v1` -* `PriorityLevelConfiguration` needs to be migrated from `flowcontrol.apiserver.k8s.io/v1beta3` to `flowcontrol.apiserver.k8s.io/v1`. -+ -This migration includes one notable change in the `spec.limited.nominalConcurrencyShares` field, which now only defaults to `30` when unspecified - an explicit value of `0` is left unchanged. -+ -For more information, see https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html/release_notes/ocp-4-19-release-notes#ocp-4-19-removed-kube-1-32-apis_release-notes[APIs removed from Kubernetes 1.32]. From 16c21368698f984ef8a0a5cf35767e78d0f6a83d Mon Sep 17 00:00:00 2001 From: Schemen Date: Tue, 12 May 2026 14:35:16 +0200 Subject: [PATCH 2/4] Satisfy Microsoft.Contractions --- docs/modules/ROOT/pages/references/release_notes.adoc | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/docs/modules/ROOT/pages/references/release_notes.adoc b/docs/modules/ROOT/pages/references/release_notes.adoc index cfecda33..b89b3542 100644 --- a/docs/modules/ROOT/pages/references/release_notes.adoc +++ b/docs/modules/ROOT/pages/references/release_notes.adoc @@ -15,7 +15,7 @@ OpenShift 4.21 improves autoscaling. The Cluster Resource Override Operator, Clu In addition, the Cluster Autoscaler can now be configured to cordon nodes before draining and removing them, giving administrators safer control over scale-down operations. Linux PSI monitoring is now available:: -Linux Pressure Stall Information is a kernel feature that measures how much time tasks spend stalled because they cannot get CPU, memory, or I/O when they need it. This will be helpful to detect clusters at risk of overload, especially in shared environments. +Linux Pressure Stall Information is a kernel feature that measures how much time tasks spend stalled because they can't get CPU, memory, or I/O when they need it. This will be helpful to detect clusters at risk of overload, especially in shared environments. The default `openshift` cluster image policy is now generally available:: Default `openshift` cluster image policy is now GA and enabled by default. Clusters upgrading from OCP 4.20 or earlier that already have a custom `ClusterImagePolicy` named `openshift` will be marked `Upgradeable=False`. Rename or recreate the custom policy under a different name, then remove the old openshift policy before upgrading. https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/nodes/#nodes-sigstore-using[You can find more information here.] @@ -25,8 +25,6 @@ End of support for vSphere 7:: Broadcom has ended general support for VMware vSphere 7 and VMware Cloud Foundation (VCF) 4. If your existing OpenShift Container Platform cluster is running on either of these platforms, you must plan to migrate or upgrade your VMware infrastructure to a supported version. - - == OpenShift 4.20 OpenShift version 4.20 is available since 2025-11-11. From ca94a4d547a63a05ba35371755fd2318b6605938 Mon Sep 17 00:00:00 2001 From: Schemen Date: Tue, 12 May 2026 15:03:02 +0200 Subject: [PATCH 3/4] Update docs/modules/ROOT/pages/references/release_notes.adoc Co-authored-by: Simon Gerber --- docs/modules/ROOT/pages/references/release_notes.adoc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/docs/modules/ROOT/pages/references/release_notes.adoc b/docs/modules/ROOT/pages/references/release_notes.adoc index b89b3542..0c2228b7 100644 --- a/docs/modules/ROOT/pages/references/release_notes.adoc +++ b/docs/modules/ROOT/pages/references/release_notes.adoc @@ -18,7 +18,7 @@ Linux PSI monitoring is now available:: Linux Pressure Stall Information is a kernel feature that measures how much time tasks spend stalled because they can't get CPU, memory, or I/O when they need it. This will be helpful to detect clusters at risk of overload, especially in shared environments. The default `openshift` cluster image policy is now generally available:: -Default `openshift` cluster image policy is now GA and enabled by default. Clusters upgrading from OCP 4.20 or earlier that already have a custom `ClusterImagePolicy` named `openshift` will be marked `Upgradeable=False`. Rename or recreate the custom policy under a different name, then remove the old openshift policy before upgrading. https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/nodes/#nodes-sigstore-using[You can find more information here.] +The default `openshift` cluster image policy is now GA and enabled by default. Clusters upgrading from OCP 4.20 or earlier that already have a custom `ClusterImagePolicy` named `openshift` will be marked `Upgradeable=False`. Rename or recreate the custom policy under a different name, then remove the old openshift policy before upgrading. https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/nodes/#nodes-sigstore-using[You can find more information here.] End of support for vSphere 7:: From 3ee2bf8173393b4ce8470b7462e3f431b53fc349 Mon Sep 17 00:00:00 2001 From: Schemen Date: Tue, 12 May 2026 15:04:30 +0200 Subject: [PATCH 4/4] Update the structure --- .../ROOT/pages/references/release_notes.adoc | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/docs/modules/ROOT/pages/references/release_notes.adoc b/docs/modules/ROOT/pages/references/release_notes.adoc index 0c2228b7..bb9623cc 100644 --- a/docs/modules/ROOT/pages/references/release_notes.adoc +++ b/docs/modules/ROOT/pages/references/release_notes.adoc @@ -11,18 +11,24 @@ Find the release notes in the upstream documentation at https://docs.redhat.com/ The https://www.redhat.com/en/blog/achieve-more-red-hat-openshift-421[Achieve more with Red Hat OpenShift 4.21] blog post is also a valuable resource. OpenShift Autoscaling gains new capabilities:: -OpenShift 4.21 improves autoscaling. The Cluster Resource Override Operator, Cluster Autoscaler, Vertical Pod Autoscaler, and Horizontal Pod Autoscaler now include network policies that restrict Operator and operand pod traffic to explicitly allowed communication only. The Vertical Pod Autoscaler can also use `InPlaceOrRecreate` mode to apply resource recommendations without recreating pods where possible, falling back to pod recreation when needed. +OpenShift 4.21 improves autoscaling. +The Cluster Resource Override Operator, Cluster Autoscaler, Vertical Pod Autoscaler, and Horizontal Pod Autoscaler now include network policies that restrict Operator and operand pod traffic to explicitly allowed communication only. +The Vertical Pod Autoscaler can also use `InPlaceOrRecreate` mode to apply resource recommendations without recreating pods where possible, falling back to pod recreation when needed. In addition, the Cluster Autoscaler can now be configured to cordon nodes before draining and removing them, giving administrators safer control over scale-down operations. Linux PSI monitoring is now available:: -Linux Pressure Stall Information is a kernel feature that measures how much time tasks spend stalled because they can't get CPU, memory, or I/O when they need it. This will be helpful to detect clusters at risk of overload, especially in shared environments. +Linux Pressure Stall Information is a kernel feature that measures how much time tasks spend stalled because they can't get CPU, memory, or I/O when they need it. +This will be helpful to detect clusters at risk of overload, especially in shared environments. The default `openshift` cluster image policy is now generally available:: -The default `openshift` cluster image policy is now GA and enabled by default. Clusters upgrading from OCP 4.20 or earlier that already have a custom `ClusterImagePolicy` named `openshift` will be marked `Upgradeable=False`. Rename or recreate the custom policy under a different name, then remove the old openshift policy before upgrading. https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/nodes/#nodes-sigstore-using[You can find more information here.] +The default `openshift` cluster image policy is now GA and enabled by default. +Clusters upgrading from OCP 4.20 or earlier that already have a custom `ClusterImagePolicy` named `openshift` will be marked `Upgradeable=False`. +Rename or recreate the custom policy under a different name, then remove the old openshift policy before upgrading. https://docs.redhat.com/en/documentation/openshift_container_platform/4.21/html-single/nodes/#nodes-sigstore-using[You can find more information here.] End of support for vSphere 7:: -Broadcom has ended general support for VMware vSphere 7 and VMware Cloud Foundation (VCF) 4. If your existing OpenShift Container Platform cluster is running on either of these platforms, you must plan to migrate or upgrade your VMware infrastructure to a supported version. +Broadcom has ended general support for VMware vSphere 7 and VMware Cloud Foundation (VCF) 4. +If your existing OpenShift Container Platform cluster is running on either of these platforms, you must plan to migrate or upgrade your VMware infrastructure to a supported version. == OpenShift 4.20