2 files changed, 52 insertions, 41 deletions

diff --git a/pkg/specgen/generate/namespaces.go b/pkg/specgen/generate/namespaces.go
index a8b74b504..5c065cdda 100644
--- a/pkg/specgen/generate/namespaces.go
+++ b/pkg/specgen/generate/namespaces.go
@@ -7,7 +7,6 @@ import (
 	"github.com/containers/common/pkg/config"
 	"github.com/containers/libpod/libpod"
 	"github.com/containers/libpod/libpod/define"
-	"github.com/containers/libpod/pkg/cgroups"
 	"github.com/containers/libpod/pkg/rootless"
 	"github.com/containers/libpod/pkg/specgen"
 	"github.com/containers/libpod/pkg/util"
@@ -49,51 +48,26 @@ func GetDefaultNamespaceMode(nsType string, cfg *config.Config, pod *libpod.Pod)
 		}
 	}
 
-	// If we have containers.conf and are not using cgroupns, use that.
-	if cfg != nil && nsType != "cgroup" {
-		switch nsType {
-		case "pid":
-			return specgen.ParseNamespace(cfg.Containers.PidNS)
-		case "ipc":
-			return specgen.ParseNamespace(cfg.Containers.IPCNS)
-		case "uts":
-			return specgen.ParseNamespace(cfg.Containers.UTSNS)
-		case "user":
-			return specgen.ParseUserNamespace(cfg.Containers.UserNS)
-		case "net":
-			ns, _, err := specgen.ParseNetworkNamespace(cfg.Containers.NetNS)
-			return ns, err
-		}
+	if cfg == nil {
+		cfg = &config.Config{}
 	}
-
 	switch nsType {
-	case "pid", "ipc", "uts":
-		// PID, IPC, UTS both default to private, do nothing
+	case "pid":
+		return specgen.ParseNamespace(cfg.Containers.PidNS)
+	case "ipc":
+		return specgen.ParseNamespace(cfg.Containers.IPCNS)
+	case "uts":
+		return specgen.ParseNamespace(cfg.Containers.UTSNS)
 	case "user":
-		// User namespace always defaults to host
-		toReturn.NSMode = specgen.Host
-	case "net":
-		// Net defaults to Slirp on rootless, Bridge otherwise.
-		if rootless.IsRootless() {
-			toReturn.NSMode = specgen.Slirp
-		} else {
-			toReturn.NSMode = specgen.Bridge
-		}
+		return specgen.ParseUserNamespace(cfg.Containers.UserNS)
 	case "cgroup":
-		// Cgroup is host for v1, private for v2.
-		// We can't trust c/common for this, as it only assumes private.
-		cgroupsv2, err := cgroups.IsCgroup2UnifiedMode()
-		if err != nil {
-			return toReturn, err
-		}
-		if !cgroupsv2 {
-			toReturn.NSMode = specgen.Host
-		}
-	default:
-		return toReturn, errors.Wrapf(define.ErrInvalidArg, "invalid namespace type %s passed", nsType)
+		return specgen.ParseCgroupNamespace(cfg.Containers.CgroupNS)
+	case "net":
+		ns, _, err := specgen.ParseNetworkNamespace(cfg.Containers.NetNS)
+		return ns, err
 	}
 
-	return toReturn, nil
+	return toReturn, errors.Wrapf(define.ErrInvalidArg, "invalid namespace type %q passed", nsType)
 }
 
 // GenerateNamespaceOptions generates container creation options for all
diff --git a/pkg/specgen/namespaces.go b/pkg/specgen/namespaces.go
index 396563267..11dee1986 100644
--- a/pkg/specgen/namespaces.go
+++ b/pkg/specgen/namespaces.go
@@ -3,6 +3,8 @@ package specgen
 import (
 	"strings"
 
+	"github.com/containers/libpod/pkg/cgroups"
+	"github.com/containers/libpod/pkg/rootless"
 	"github.com/pkg/errors"
 )
 
@@ -163,7 +165,7 @@ func ParseNamespace(ns string) (Namespace, error) {
 		toReturn.NSMode = FromPod
 	case ns == "host":
 		toReturn.NSMode = Host
-	case ns == "private":
+	case ns == "private", ns == "":
 		toReturn.NSMode = Private
 	case strings.HasPrefix(ns, "ns:"):
 		split := strings.SplitN(ns, ":", 2)
@@ -186,6 +188,31 @@ func ParseNamespace(ns string) (Namespace, error) {
 	return toReturn, nil
 }
 
+// ParseCgroupNamespace parses a cgroup namespace specification in string
+// form.
+func ParseCgroupNamespace(ns string) (Namespace, error) {
+	toReturn := Namespace{}
+	// Cgroup is host for v1, private for v2.
+	// We can't trust c/common for this, as it only assumes private.
+	cgroupsv2, err := cgroups.IsCgroup2UnifiedMode()
+	if err != nil {
+		return toReturn, err
+	}
+	if cgroupsv2 {
+		switch ns {
+		case "host":
+			toReturn.NSMode = Host
+		case "private", "":
+			toReturn.NSMode = Private
+		default:
+			return toReturn, errors.Errorf("unrecognized namespace mode %s passed", ns)
+		}
+	} else {
+		toReturn.NSMode = Host
+	}
+	return toReturn, nil
+}
+
 // ParseUserNamespace parses a user namespace specification in string
 // form.
 func ParseUserNamespace(ns string) (Namespace, error) {
@@ -205,6 +232,9 @@ func ParseUserNamespace(ns string) (Namespace, error) {
 	case ns == "keep-id":
 		toReturn.NSMode = KeepID
 		return toReturn, nil
+	case ns == "":
+		toReturn.NSMode = Host
+		return toReturn, nil
 	}
 	return ParseNamespace(ns)
 }
@@ -215,11 +245,18 @@ func ParseUserNamespace(ns string) (Namespace, error) {
 func ParseNetworkNamespace(ns string) (Namespace, []string, error) {
 	toReturn := Namespace{}
 	var cniNetworks []string
+	// Net defaults to Slirp on rootless
 	switch {
 	case ns == "slirp4netns":
 		toReturn.NSMode = Slirp
 	case ns == "pod":
 		toReturn.NSMode = FromPod
+	case ns == "":
+		if rootless.IsRootless() {
+			toReturn.NSMode = Slirp
+		} else {
+			toReturn.NSMode = Bridge
+		}
 	case ns == "bridge":
 		toReturn.NSMode = Bridge
 	case ns == "none":