Merge pull request #286 from AkihiroSuda/oci-worker-overlay-false

worker/oci: allow using naive snapshotter

cmd/buildkitd/main_oci_worker.go

@@ -27,6 +27,12 @@ func init() {
 			Name:  "oci-worker-labels",
 			Usage: "user-specific annotation labels (com.example.foo=bar)",
 		},
+		cli.StringFlag{
+			Name:  "oci-worker-snapshotter",
+			Usage: "name of snapshotter (overlayfs or naive)",
+			// TODO(AkihiroSuda): autodetect overlayfs availability when the value is set to "auto"?
+			Value: "overlayfs",
+		},
 	)
 	// TODO: allow multiple oci runtimes and snapshotters
 }
@@ -43,7 +49,7 @@ func ociWorkerInitializer(c *cli.Context, common workerInitializerOpt) ([]worker
 	if err != nil {
 		return nil, err
 	}
-	opt, err := runc.NewWorkerOpt(common.root, labels)
+	opt, err := runc.NewWorkerOpt(common.root, labels, c.GlobalString("oci-worker-snapshotter"))
 	if err != nil {
 		return nil, err
 	}

worker/runc/runc.go

@@ -11,19 +11,30 @@ import (
 	"github.com/containerd/containerd/diff/walking"
 	ctdmetadata "github.com/containerd/containerd/metadata"
 	ctdsnapshot "github.com/containerd/containerd/snapshots"
+	"github.com/containerd/containerd/snapshots/naive"
 	"github.com/containerd/containerd/snapshots/overlay"
 	"github.com/moby/buildkit/cache/metadata"
 	"github.com/moby/buildkit/executor/runcexecutor"
 	containerdsnapshot "github.com/moby/buildkit/snapshot/containerd"
 	"github.com/moby/buildkit/worker/base"
+	"github.com/pkg/errors"
 )
 
 // NewWorkerOpt creates a WorkerOpt.
 // But it does not set the following fields:
 //  - SessionManager
-func NewWorkerOpt(root string, labels map[string]string) (base.WorkerOpt, error) {
+func NewWorkerOpt(root string, labels map[string]string, snapshotterName string) (base.WorkerOpt, error) {
 	var opt base.WorkerOpt
-	name := "runc-overlayfs"
+	var snapshotterNew func(root string) (ctdsnapshot.Snapshotter, error)
+	switch snapshotterName {
+	case "naive":
+		snapshotterNew = naive.NewSnapshotter
+	case "overlayfs": // not "overlay", for consistency with containerd snapshotter plugin ID.
+		snapshotterNew = overlay.NewSnapshotter
+	default:
+		return opt, errors.Errorf("unknown snapshotter name: %q", snapshotterName)
+	}
+	name := "runc-" + snapshotterName
 	root = filepath.Join(root, name)
 	if err := os.MkdirAll(root, 0700); err != nil {
 		return opt, err
@@ -36,7 +47,7 @@ func NewWorkerOpt(root string, labels map[string]string) (base.WorkerOpt, error)
 	if err != nil {
 		return opt, err
 	}
-	s, err := overlay.NewSnapshotter(filepath.Join(root, "snapshots"))
+	s, err := snapshotterNew(filepath.Join(root, "snapshots"))
 	if err != nil {
 		return opt, err
 	}
@@ -52,7 +63,7 @@ func NewWorkerOpt(root string, labels map[string]string) (base.WorkerOpt, error)
 	}
 
 	mdb := ctdmetadata.NewDB(db, c, map[string]ctdsnapshot.Snapshotter{
-		"overlayfs": s,
+		snapshotterName: s,
 	})
 	if err := mdb.Init(context.TODO()); err != nil {
 		return opt, err
@@ -69,7 +80,7 @@ func NewWorkerOpt(root string, labels map[string]string) (base.WorkerOpt, error)
 	if err != nil {
 		return opt, err
 	}
-	xlabels := base.Labels("oci", "overlayfs")
+	xlabels := base.Labels("oci", snapshotterName)
 	for k, v := range labels {
 		xlabels[k] = v
 	}
@@ -78,7 +89,7 @@ func NewWorkerOpt(root string, labels map[string]string) (base.WorkerOpt, error)
 		Labels:        xlabels,
 		MetadataStore: md,
 		Executor:      exe,
-		Snapshotter:   containerdsnapshot.NewSnapshotter(mdb.Snapshotter("overlayfs"), c, md, "buildkit", gc),
+		Snapshotter:   containerdsnapshot.NewSnapshotter(mdb.Snapshotter(snapshotterName), c, md, "buildkit", gc),
 		ContentStore:  c,
 		Applier:       apply.NewFileSystemApplier(c),
 		Differ:        walking.NewWalkingDiff(c),

worker/runc/runc_test.go

@@ -38,7 +38,7 @@ func TestRuncWorker(t *testing.T) {
 	require.NoError(t, err)
 	defer os.RemoveAll(tmpdir)
 
-	workerOpt, err := NewWorkerOpt(tmpdir, nil)
+	workerOpt, err := NewWorkerOpt(tmpdir, nil, "overlayfs")
 	require.NoError(t, err)
 
 	workerOpt.SessionManager, err = session.NewManager()