add a command to list kernel tags and pull kernels built by little-vm-helper-images

README.md

@@ -18,9 +18,10 @@ For an example script, see [scripts/example.sh](scripts/example.sh).
 LVH can be used to:
  * build root images for VMs
  * build kernels
+ * download kernels
  * boot VMs using above
 
-### Root images
+### Build root images
 
 Build example images:
 ```bash
@@ -79,7 +80,7 @@ $ ls -sh1 _data/images/*.img
 1.7G _data/images/k8s.img
 ```
 
-### Kernels
+### Build kernels
 
 ```bash
 $ mkdir -p _data/kernels
@@ -129,6 +130,53 @@ git/
 Currently, kernels are built using the `bzImage` for x86\_64 or `Image.gz` for
 arm64, and `tar-pkg` targets (see [pkg/kernels/conf.go](pkg/kernels/conf.go)).
 
+### Download kernels
+
+List the available versions
+
+```console
+$ lvh kernels catalog
+bpf-next
+rhel8
+4.9
+4.19
+[...]
+6.3
+6.6
+```
+
+Retrieve the tags for a given version:
+```console
+$ lvh kernels catalog 6.6
+6.6-20240123.120815
+6.6-20240123.175813
+[...]
+6.6-20240404.144247
+6.6-20240408.100959
+6.6-main
+```
+
+See `lvh kernels catalog --help` for more details.
+
+Download the kernel and related artifacts (BTF, modules, etc.)
+
+```console
+$ lvh kernels pull 6.6-main
+$ find 6.6-main/ -maxdepth 3
+6.6-main/
+6.6-main/boot
+6.6-main/boot/vmlinuz-6.6.25
+6.6-main/boot/btf-6.6.25
+6.6-main/boot/System.map-6.6.25
+6.6-main/boot/vmlinux-6.6.25
+6.6-main/boot/config-6.6.25
+6.6-main/lib
+6.6-main/lib/modules
+6.6-main/lib/modules/6.6.25
+```
+
+See `lvh kernels pull --help` for more details.
+
 ### Booting images
 
 You can use the `run` subcommand to start images.

cmd/lvh/kernels/add.go

@@ -70,5 +70,7 @@ func addCommand() *cobra.Command {
 	addCmd.Flags().BoolVar(&addPrintConfig, "just-print-config", false, "do not actually add the kernel. Just print its config.")
 	addCmd.Flags().BoolVar(&addFetch, "fetch", false, "fetch URL")
 	addCmd.Flags().BoolVar(&backupConf, "backup-conf", false, "backup configuration")
+	addCmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	addCmd.MarkFlagRequired(dirNameCommand)
 	return addCmd
 }

cmd/lvh/kernels/build.go

@@ -26,6 +26,8 @@ func buildCommand() *cobra.Command {
 	}
 
 	cmd.Flags().StringVar(&arch, "arch", "", "target architecture to build the kernel, e.g. 'amd64' or 'arm64' (default to native architecture)")
+	cmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	cmd.MarkFlagRequired(dirNameCommand)
 
 	return cmd
 }

cmd/lvh/kernels/catalog.go

@@ -0,0 +1,103 @@
+package kernels
+
+import (
+	"fmt"
+	"regexp"
+	"slices"
+	"strings"
+
+	"github.com/google/go-containerregistry/pkg/crane"
+	"github.com/spf13/cobra"
+	"golang.org/x/mod/semver"
+)
+
+const (
+	kernelImageRepository = "quay.io/lvh-images/kernel-images"
+
+	kernelTagRegex = `^(.+)-([0-9]+\.[0-9]+|main)$`
+
+	repoCommand = "repo"
+	repoHelp    = "specify the OCI repository to pull the image from"
+)
+
+func catalogCommand() *cobra.Command {
+	var (
+		repo string
+	)
+
+	cmd := &cobra.Command{
+		Use:   "catalog [version]",
+		Short: "list available tags for kernel images from cilium/little-vm-helper-images",
+		Long: `List the available tags for kernel images built from cilium/little-vm-helper-images
+
+Examples:
+  # List all available versions
+  lvh kernels catalog
+
+  # List the tags available for version 6.6
+  lvh kernels catalog 6.6
+
+  # Retrieve the latest tags available for version bpf-next
+  lvh kernels catalog bpf-next | tail -n 2
+
+  # Retrieve the latest CI-generated images for version bpf-next
+  lvh kernels catalog bpf-next --repo quay.io/lvh-images/kernel-images-ci`,
+		RunE: func(cmd *cobra.Command, args []string) error {
+			re := regexp.MustCompile(kernelTagRegex)
+
+			rawTagList, err := crane.ListTags(repo)
+			if err != nil {
+				return err
+			}
+
+			tags := map[string][]string{}
+			for _, tag := range rawTagList {
+				match := re.FindStringSubmatch(tag)
+				if len(match) < 3 {
+					// discard most of the tags that don't match the regex
+					continue
+				}
+
+				if strings.Contains(match[1], "-latest") {
+					// remove some tags with "-latest" that are obsolete
+					continue
+				}
+
+				tags[match[1]] = append(tags[match[1]], match[0])
+			}
+
+			if len(args) == 0 {
+				versions := []string{}
+				for v := range tags {
+					// semver package needs the v Prefix
+					versions = append(versions, "v"+v)
+				}
+				semver.Sort(versions)
+				for _, v := range versions {
+					cmd.Println(strings.TrimPrefix(v, "v"))
+				}
+				return nil
+			}
+
+			if _, found := tags[args[0]]; !found {
+				keys := []string{}
+				for key := range tags {
+					keys = append(keys, key)
+				}
+				return fmt.Errorf("kernel version not found, try: %s", keys)
+			}
+
+			for key := range tags {
+				slices.Sort(tags[key])
+			}
+			for _, tag := range tags[args[0]] {
+				cmd.Println(tag)
+			}
+			return nil
+		},
+	}
+
+	cmd.Flags().StringVar(&repo, repoCommand, kernelImageRepository, repoHelp)
+
+	return cmd
+}

cmd/lvh/kernels/configure.go

@@ -37,6 +37,8 @@ func configureCommand() *cobra.Command {
 	}
 
 	cmd.Flags().String(archFlag, "", archHelp)
+	cmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	cmd.MarkFlagRequired("dir")
 
 	return cmd
 }
@@ -66,6 +68,8 @@ func rawConfigureCommand() *cobra.Command {
 	}
 
 	cmd.Flags().String(archFlag, "", archHelp)
+	cmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	cmd.MarkFlagRequired(dirNameCommand)
 
 	return cmd
 }

cmd/lvh/kernels/fetch.go

@@ -12,7 +12,7 @@ import (
 )
 
 func fetchCommand() *cobra.Command {
-	return &cobra.Command{
+	cmd := &cobra.Command{
 		Use:   "fetch <kernel>",
 		Short: "fetch kernel",
 		Args:  cobra.ExactArgs(1),
@@ -22,4 +22,9 @@ func fetchCommand() *cobra.Command {
 			return kernels.FetchKernel(context.Background(), log, dirName, kname)
 		},
 	}
+
+	cmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	cmd.MarkFlagRequired(dirNameCommand)
+
+	return cmd
 }

cmd/lvh/kernels/init.go

@@ -45,5 +45,7 @@ func initCommand() *cobra.Command {
 			strings.Join(kernels.GetConfigGroupNames(), ","),
 		),
 	)
+	cmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	cmd.MarkFlagRequired(dirNameCommand)
 	return cmd
 }

cmd/lvh/kernels/kernels.go

@@ -9,15 +9,18 @@ import (
 
 var dirName string
 
+const (
+	dirNameHelp    = "directory to place kernels"
+	dirNameCommand = "dir"
+)
+
 func KernelsCommand() *cobra.Command {
 	cmd := &cobra.Command{
-		Use:   "kernels",
-		Short: "build kernels",
+		Use:     "kernels",
+		Aliases: []string{"kernel", "k"},
+		Short:   "build and pull kernels",
 	}
 
-	cmd.PersistentFlags().StringVar(&dirName, "dir", "", "directory to to place kernels")
-	cmd.MarkPersistentFlagRequired("dir")
-
 	cmd.AddCommand(
 		initCommand(),
 		listCommand(),
@@ -27,6 +30,8 @@ func KernelsCommand() *cobra.Command {
 		rawConfigureCommand(),
 		buildCommand(),
 		fetchCommand(),
+		catalogCommand(),
+		pullCommand(),
 	)
 
 	return cmd

cmd/lvh/kernels/list.go

@@ -12,7 +12,7 @@ import (
 )
 
 func listCommand() *cobra.Command {
-	return &cobra.Command{
+	cmd := &cobra.Command{
 		Use:   "list",
 		Short: "list available kernels (by reading config file in directory)",
 		Run: func(cmd *cobra.Command, _ []string) {
@@ -27,4 +27,9 @@ func listCommand() *cobra.Command {
 			}
 		},
 	}
+
+	cmd.Flags().StringVar(&dirName, dirNameCommand, "", dirNameHelp)
+	cmd.MarkFlagRequired(dirNameCommand)
+
+	return cmd
 }