MCO-2028: Add target OS version detection

Change package installation during kernel switches to derive
the OS version from the target rpm-ostree deployment instead
of the current running version.

Treating the OS version as static caused failures during major
version upgrades due to package discrepancies. This fix ensures
package resolution targets the new OS version.

Signed-off-by: Pablo Rodriguez Nava <git@amail.pablintino.com>

Author: Pablo Rodriguez Nava

pkg/daemon/rpm-ostree.go

@@ -229,6 +229,38 @@ func (r *RpmOstreeClient) RebaseLayeredFromContainerStorage(podmanImageInfo *Pod
 	return runRpmOstree("rebase", "--experimental", "ostree-unverified-image:containers-storage:"+podmanImageInfo.RepoDigest)
 }
 
+// DeploymentVersion wraps rpm-ostree deployment information to provide
+// version checking methods similar to the osrelease package.
+type DeploymentVersion struct {
+	// osName is the osname field from the deployment
+	osName string
+	// version is the version field from the deployment
+	version string
+}
+
+// NewTargetOSVersionFromDeployment creates a DeploymentVersion from the given deployment
+func NewTargetOSVersionFromDeployment(deployment *rpmostreeclient.Deployment) *DeploymentVersion {
+	return &DeploymentVersion{
+		osName:  deployment.OSName,
+		version: deployment.Version,
+	}
+}
+
+// BaseVersionMajor returns the first number in a `.` separated version.
+func (t *DeploymentVersion) BaseVersionMajor() string {
+	return strings.Split(t.version, ".")[0]
+}
+
+// IsEL is true if the OS is an Enterprise Linux variant of CoreOS
+func (t *DeploymentVersion) IsEL() bool {
+	return t.osName == "rhcos" || t.osName == "scos"
+}
+
+// IsEL10 is true if the target OS is RHCOS 10 or SCOS 10
+func (t *DeploymentVersion) IsEL10() bool {
+	return t.IsEL() && (strings.HasPrefix(t.version, "10.") || t.version == "10")
+}
+
 // patchPoliciesForContainerStorage temporarily overrides the container image policy visible
 // to rpm-ostreed to ensure pulls from the "containers-storage" transport are allowed for the
 // given image.

pkg/daemon/update.go

@@ -1722,7 +1722,10 @@ func (dn *CoreOSDaemon) switchKernel(oldConfig, newConfig *mcfgv1.MachineConfig)
 		logSystem("Re-applying kernel type %s", newKtype)
 	}
 
-	kernelPackages := dn.getKernelPackagesForRelease()
+	kernelPackages, err := dn.getKernelPackagesForTargetRelease()
+	if err != nil {
+		return fmt.Errorf("failed to get kernel packages for target release: %w", err)
+	}
 	if newKtype == ctrlcommon.KernelTypeRealtime {
 		// Switch to RT kernel
 		args := []string{"override", "remove"}
@@ -1745,10 +1748,22 @@ func (dn *CoreOSDaemon) switchKernel(oldConfig, newConfig *mcfgv1.MachineConfig)
 	return fmt.Errorf("unhandled kernel type %s", newKtype)
 }
 
-// getKernelPackagesForRelease returns the list of kernel packaged for the running OS release.
-func (dn *CoreOSDaemon) getKernelPackagesForRelease() releaseKernelPackages {
+// getKernelPackagesForTargetRelease returns the list of kernel packaged for the running OS release.
+func (dn *CoreOSDaemon) getKernelPackagesForTargetRelease() (releaseKernelPackages, error) {
 	// TODO: Drop this code and use https://github.com/coreos/rpm-ostree/issues/2542 instead
 
+	// Fetch the OS deployments to infer the target OS version from them
+	booted, staged, err := dn.NodeUpdaterClient.GetBootedAndStagedDeployment()
+	if err != nil {
+		return releaseKernelPackages{}, fmt.Errorf("error fetching OS deployments : %v", err)
+	}
+
+	// If there's a staged deployment the packages will be installed in it instead of in the current booted deployment
+	targetDeployment := booted
+	if staged != nil {
+		targetDeployment = staged
+	}
+
 	kernelPackages := releaseKernelPackages{
 		defaultKernel:   []string{"kernel", "kernel-core", "kernel-modules", "kernel-modules-core", "kernel-modules-extra"},
 		hugePagesKernel: []string{"kernel-64k-core", "kernel-64k-modules", "kernel-64k-modules-core", "kernel-64k-modules-extra"},
@@ -1759,10 +1774,11 @@ func (dn *CoreOSDaemon) getKernelPackagesForRelease() releaseKernelPackages {
 
 	// RHEL10 early bugfix of OCPBUGS-62925
 	// RHEL10 doesn't ship with kernel-rt-kvm
-	if !dn.os.IsEL10() {
+	targetVersion := NewTargetOSVersionFromDeployment(targetDeployment)
+	if !targetVersion.IsEL10() {
 		kernelPackages.realtimeKernel = append(kernelPackages.realtimeKernel, "kernel-rt-kvm")
 	}
-	return kernelPackages
+	return kernelPackages, nil
 }
 
 // updateFiles writes files specified by the nodeconfig to disk. it also writes