buildah: new global option --cgroup-manager

allow to override the cgroup manager with a global option
--cgroup-manager=MANAGER that has the same semantic as Podman.

Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>

cmd/buildah/main.go

@@ -39,6 +39,7 @@ type globalFlags struct {
 	cpuProfileFile             *os.File
 	MemoryProfile              string
 	UserShortNameAliasConfPath string
+	CgroupManager              string
 }
 
 var rootCmd = &cobra.Command{
@@ -77,6 +78,13 @@ func init() {
 		defaultStoreDriverOptions = optionSlice
 	}
 
+	containerConfig, err := config.Default()
+	if err != nil {
+		logrus.Errorf(err.Error())
+		os.Exit(1)
+	}
+	containerConfig.CheckCgroupsAndAdjustConfig()
+
 	cobra.OnInitialize(initConfig)
 	// Disable the implicit `completion` command in cobra.
 	rootCmd.CompletionOptions.DisableDefaultCmd = true
@@ -89,6 +97,7 @@ func init() {
 	rootCmd.PersistentFlags().StringVar(&globalFlagResults.UserShortNameAliasConfPath, "short-name-alias-conf", "", "path to short name alias cache file (not usually used)")
 	rootCmd.PersistentFlags().StringVar(&globalFlagResults.Root, "root", storageOptions.GraphRoot, "storage root dir")
 	rootCmd.PersistentFlags().StringVar(&globalFlagResults.RunRoot, "runroot", storageOptions.RunRoot, "storage state dir")
+	rootCmd.PersistentFlags().StringVar(&globalFlagResults.CgroupManager, "cgroup-manager", containerConfig.Engine.CgroupManager, "cgroup manager")
 	rootCmd.PersistentFlags().StringVar(&globalFlagResults.StorageDriver, "storage-driver", storageOptions.GraphDriverName, "storage-driver")
 	rootCmd.PersistentFlags().StringSliceVar(&globalFlagResults.StorageOpts, "storage-opt", defaultStoreDriverOptions, "storage driver option")
 	rootCmd.PersistentFlags().StringSliceVar(&globalFlagResults.UserNSUID, "userns-uid-map", []string{}, "default `ctrID:hostID:length` UID mapping to use")

cmd/buildah/run.go

@@ -160,6 +160,7 @@ func runCmd(c *cobra.Command, args []string, iopts runInputOptions) error {
 	options.Mounts = mounts
 	// Run() will automatically clean them up.
 	options.ExternalImageMounts = mountedImages
+	options.CgroupManager = globalFlagResults.CgroupManager
 
 	runerr := builder.Run(args, options)
 

contrib/completions/bash/buildah

@@ -171,6 +171,7 @@ return 1
          --version -v
          "
      local options_with_args="
+         --cgroup-manager
          --registries-conf
          --registries-conf-dir
          --root
@@ -200,6 +201,10 @@ return 1
              COMPREPLY=($(compgen -W 'devicemapper overlay2' -- "$cur"))
              return
              ;;
+         --cgroup-manager)
+             COMPREPLY=($(compgen -W 'cgroupfs systemd' -- "$cur"))
+             return
+             ;;
          $(__buildah_to_extglob "$options_with_args"))
  return
  ;;

docs/buildah.1.md

@@ -20,6 +20,13 @@ The Buildah package provides a command line tool which can be used to:
 
 ## OPTIONS
 
+**--cgroup-manager**=*manager*
+
+The CGroup manager to use for container cgroups. Supported values are cgroupfs or systemd. Default is systemd unless overridden in the containers.conf file.
+
+Note: Setting this flag can cause certain commands to break when called on containers previously created by the other CGroup manager type.
+Note: CGroup manager is not supported in rootless mode when using CGroups Version V1.
+
 **--log-level** **value**
 
 The log level to be used. Either "trace", "debug", "info", "warn", "error", "fatal", or "panic", defaulting to "warn".

run.go

@@ -157,6 +157,8 @@ type RunOptions struct {
 	ExternalImageMounts []string
 	// System context of current build
 	SystemContext *types.SystemContext
+	// CgroupManager to use for running OCI containers
+	CgroupManager string
 }
 
 // RunMountArtifacts are the artifacts created when using a run mount.