Chapter 1. Red Hat build of MicroShift 4.18 release notes Red Hat build of MicroShift (MicroShift) provides developers and IT organizations with small-form-factor and edge computing delivered as an application that customers can deploy on top of their managed Red Hat Enterprise Linux (RHEL) devices at the edge. Built on OpenShift Container Platform and Kubernetes, MicroShift provides an efficient way to operate single-node clusters in low-resource edge environments. MicroShift is designed to make control plane restarts economical and be lifecycle-managed as a single unit by the operating system. Updates, roll-backs, and configuration changes consist of simply staging another version in parallel and then - without relying on a network - flipping to and from that version and restarting. 1.1. About this release Version 4.18 of MicroShift includes new features and enhancements. Update to the latest version of MicroShift to receive all of the latest features, bug fixes, and security updates. MicroShift is derived from OpenShift Container Platform 4.18 and uses the CRI-O container runtime. New features, changes, and known issues that pertain to MicroShift are included in this topic. You can deploy MicroShift clusters to on-premise, cloud, disconnected, and offline environments. MicroShift 4.18 is supported on Red Hat Enterprise Linux (RHEL) 9.4. For lifecycle information, see the Red Hat build of MicroShift Life Cycle Policy . 1.2. New features and enhancements This release adds improvements related to the following components and concepts. 1.2.1. Updating Updating two minor EUS versions in a single step is supported in 4.18. Updates for both single-version minor releases and patch releases are also supported. See Update options with Red Hat build of MicroShift and Red Hat Device Edge for details. 1.2.2. Configuring 1.2.2.1. Drop-in configuration snippets now available With this release, make configuring your MicroShift instances easier by using drop-in configuration snippets. See Using configuration snippets for details. 1.2.2.2. Control ingress for your use case with additional parameters With this update, you have greater control over ingress to your MicroShift cluster by configuring more parameters. You can use these parameters to define secure connections and the number of connections per pod, plus more. See Using ingress control for a MicroShift cluster for details. 1.2.3. Running applications 1.2.3.1. Deleting or updating Kustomize manifest resources now documented With this release, you can delete or upgrade the Kustomize manifest resources. For more information, see Deleting or updating Kustomize manifest resources . 1.2.3.2. Greenboot example outputs for image mode for RHEL available With this release, you can see detailed explanations and example outputs to check whether greenboot workload scripts are running properly. For more information, see Testing a workload health check script . 1.2.4. Backup and restore 1.2.4.1. Automated recovery from manual backups With this release, you can automatically restore data from manual backups when MicroShift fails to start by using the auto-recovery feature. For more information, see Automated recovery from manual backups . 1.2.5. Documentation enhancements 1.2.5.1. Updated content in the RHEL image mode section With this release, the contents of the "Installing with RHEL image mode" section, which were previously developer-focused, are now updated to be MicroShift administrator-focused. For more information, see Using image mode for RHEL with MicroShift . 1.3. Technology Preview features Some features in this release are currently in Technology Preview. These experimental features are not intended for production use. Note the following scope of support on the Red Hat Customer Portal for these features: Technology Preview Features Support Scope 1.3.1. Red Hat Enterprise Linux (RHEL) image mode Technology Preview feature You can install MicroShift using a bootc container image. Image mode for RHEL is a Technology Preview deployment method that uses a container-native approach to build, deploy and manage the operating system as a bootc container image. See Using image mode for RHEL with MicroShift for more information. 1.4. Deprecated and removed features With this release, the CSI snapshot webhook feature available in releases is removed. The webhook is replaced by CEL validation rules for snapshot objects. 1.5. Bug fixes Installation Previously, the greenboot health check marked some healthy Image mode for RHEL systems as unhealthy due to a 300-second timeout, which was insufficient for systems with slow networks. Beginning in Red Hat build of MicroShift 4.18, the default greenboot wait timeout has been extended to 600 seconds to provide more time to download images and ensure accurate system checks. ( OCPBUGS-47463 ) 1.6. Additional release notes Release notes for related components and products are available in the following documentation: Note The following release notes are for downstream Red Hat products only; upstream or community release notes for related products are not included. 1.6.1. GitOps release notes See Red Hat OpenShift GitOps 1.15: Highlights of what is new and what has changed with this OpenShift GitOps release for more information. You can also go to the Red Hat package download page and search for "gitops" if you just need the latest package, Red Hat packages . 1.6.2. OpenShift Container Platform release notes See the OpenShift Container Platform Release Notes for information about the Operator Lifecycle Manager and other components. Not all of the changes to OpenShift Container Platform apply to MicroShift. See the specific MicroShift implementation of an Operator or function for more information. 1.6.3. Red Hat Enterprise Linux (RHEL) release notes See the Release Notes for Red Hat Enterprise Linux 9.4 for more information about RHEL. 1.7. Asynchronous errata updates Security, bug fix, and enhancement updates for MicroShift 4.18 are released as asynchronous errata through the Red Hat Network. All MicroShift 4.18 errata are available on the Red Hat Customer Portal . For more information about asynchronous errata, read the MicroShift Life Cycle . Red Hat Customer Portal users can enable errata notifications in the account settings for Red Hat Subscription Management (RHSM). When errata notifications are enabled, you are notified through email whenever new errata relevant to your registered systems are released. Note Red Hat Customer Portal user accounts must have systems registered and consuming MicroShift entitlements for MicroShift errata notification emails to generate. This section is updated over time to provide notes on enhancements and bug fixes for future asynchronous errata releases of MicroShift 4.18. Versioned asynchronous releases, for example with the form MicroShift 4.18.z, are detailed in the following subsections. MicroShift uses a priority-based release cadence to provide the most important updates with the least disruption. Important For any Red Hat build of MicroShift release, always review the Update options with Red Hat build of MicroShift and Red Hat Device Edge documentation before proceeding with an update. 1.7.1. RHEA-2024:6124 - MicroShift 4.18.1 bug fix and security update advisory Issued: 25 February 2025 Red Hat build of MicroShift release 4.18.1 is now available. Bug fixes and enhancements are listed in the RHEA-2024:6124 advisory. Release notes for bug fixes and enhancements are provided in this documentation. The images that are included in the update are provided by the OpenShift Container Platform RHSA-2024:6122 advisory. See the latest images included with MicroShift by listing the contents of the MicroShift RPM release package . 1.7.1.1. Known issue A failed greenboot health check flag does not clear when an RPM-install-based MicroShift service is updated without rebooting the system. As a consequence, greenboot health checks for optional components continue to fail because the systemctl restart greenboot-healthcheck.service command fails while the flag is present. ( OCPBUGS-51198 ) 1.7.2. RHBA-2025:1953 - MicroShift 4.18.2 bug fix and enhancement advisory Issued: 4 March 2025 Red Hat build of MicroShift release 4.18.2 is now available. Bug fixes and enhancements are listed in the RHBA-2025:1953 advisory. Release notes for bug fixes and enhancements are provided in this documentation. The images that are included in the update are provided by the OpenShift Container Platform RHBA-2025:1904 advisory. See the latest images included with MicroShift by listing the contents of the MicroShift RPM release package . 1.7.2.1. Bug fix Previously, a failed greenboot health check flag did not clear when an RPM-install-based MicroShift service was updated without rebooting the system. As a consequence, greenboot health checks for optional components continue to fail because the systemctl restart greenboot-healthcheck.service command fails while the flag is present. With this release, the primary MicroShift greenboot health check clears the condition that causes optional component health checks to continue to fail. ( OCPBUGS-51198 )

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