Merge pull request #3509 from giuseppe/cgroup-namespace

libpod: support for cgroup namespace

3 files changed, 97 insertions, 0 deletions

diff --git a/pkg/namespaces/namespaces.go b/pkg/namespaces/namespaces.go
index ec9276344..7ed95bd0f 100644
--- a/pkg/namespaces/namespaces.go
+++ b/pkg/namespaces/namespaces.go
@@ -4,6 +4,63 @@ import (
 	"strings"
 )
 
+// CgroupMode represents cgroup mode in the container.
+type CgroupMode string
+
+// IsHost indicates whether the container uses the host's cgroup.
+func (n CgroupMode) IsHost() bool {
+	return n == "host"
+}
+
+// IsNS indicates a cgroup namespace passed in by path (ns:<path>)
+func (n CgroupMode) IsNS() bool {
+	return strings.HasPrefix(string(n), "ns:")
+}
+
+// NS gets the path associated with a ns:<path> cgroup ns
+func (n CgroupMode) NS() string {
+	parts := strings.SplitN(string(n), ":", 2)
+	if len(parts) > 1 {
+		return parts[1]
+	}
+	return ""
+}
+
+// IsContainer indicates whether the container uses a new cgroup namespace.
+func (n CgroupMode) IsContainer() bool {
+	parts := strings.SplitN(string(n), ":", 2)
+	return len(parts) > 1 && parts[0] == "container"
+}
+
+// Container returns the name of the container whose cgroup namespace is going to be used.
+func (n CgroupMode) Container() string {
+	parts := strings.SplitN(string(n), ":", 2)
+	if len(parts) > 1 {
+		return parts[1]
+	}
+	return ""
+}
+
+// IsPrivate indicates whether the container uses the a private cgroup.
+func (n CgroupMode) IsPrivate() bool {
+	return n == "private"
+}
+
+// Valid indicates whether the Cgroup namespace is valid.
+func (n CgroupMode) Valid() bool {
+	parts := strings.Split(string(n), ":")
+	switch mode := parts[0]; mode {
+	case "", "host", "private", "ns":
+	case "container":
+		if len(parts) != 2 || parts[1] == "" {
+			return false
+		}
+	default:
+		return false
+	}
+	return true
+}
+
 // UsernsMode represents userns mode in the container.
 type UsernsMode string
 
diff --git a/pkg/spec/createconfig.go b/pkg/spec/createconfig.go
index 0042ed401..1fb1f829b 100644
--- a/pkg/spec/createconfig.go
+++ b/pkg/spec/createconfig.go
@@ -63,6 +63,7 @@ type CreateConfig struct {
 	CapDrop            []string // cap-drop
 	CidFile            string
 	ConmonPidFile      string
+	Cgroupns           string
 	CgroupParent       string // cgroup-parent
 	Command            []string
 	Detach             bool              // detach
@@ -101,6 +102,7 @@ type CreateConfig struct {
 	NetworkAlias       []string               //network-alias
 	PidMode            namespaces.PidMode     //pid
 	Pod                string                 //pod
+	CgroupMode         namespaces.CgroupMode  //cgroup
 	PortBindings       nat.PortMap
 	Privileged         bool     //privileged
 	Publish            []string //publish
@@ -268,6 +270,23 @@ func (c *CreateConfig) getContainerCreateOptions(runtime *libpod.Runtime, pod *l
 		options = append(options, libpod.WithNetNS(portBindings, postConfigureNetNS, string(c.NetMode), networks))
 	}
 
+	if c.CgroupMode.IsNS() {
+		ns := c.CgroupMode.NS()
+		if ns == "" {
+			return nil, errors.Errorf("invalid empty user-defined network namespace")
+		}
+		_, err := os.Stat(ns)
+		if err != nil {
+			return nil, err
+		}
+	} else if c.CgroupMode.IsContainer() {
+		connectedCtr, err := runtime.LookupContainer(c.CgroupMode.Container())
+		if err != nil {
+			return nil, errors.Wrapf(err, "container %q not found", c.CgroupMode.Container())
+		}
+		options = append(options, libpod.WithCgroupNSFrom(connectedCtr))
+	}
+
 	if c.PidMode.IsContainer() {
 		connectedCtr, err := runtime.LookupContainer(c.PidMode.Container())
 		if err != nil {
diff --git a/pkg/spec/spec.go b/pkg/spec/spec.go
index 41054633f..a8ab4911a 100644
--- a/pkg/spec/spec.go
+++ b/pkg/spec/spec.go
@@ -325,6 +325,10 @@ func (config *CreateConfig) createConfigToOCISpec(runtime *libpod.Runtime, userM
 	if err := addIpcNS(config, &g); err != nil {
 		return nil, err
 	}
+
+	if err := addCgroupNS(config, &g); err != nil {
+		return nil, err
+	}
 	configSpec := g.Config
 
 	// HANDLE CAPABILITIES
@@ -622,6 +626,23 @@ func addIpcNS(config *CreateConfig, g *generate.Generator) error {
 	return nil
 }
 
+func addCgroupNS(config *CreateConfig, g *generate.Generator) error {
+	cgroupMode := config.CgroupMode
+	if cgroupMode.IsNS() {
+		return g.AddOrReplaceLinuxNamespace(string(spec.CgroupNamespace), NS(string(cgroupMode)))
+	}
+	if cgroupMode.IsHost() {
+		return g.RemoveLinuxNamespace(spec.CgroupNamespace)
+	}
+	if cgroupMode.IsPrivate() {
+		return g.AddOrReplaceLinuxNamespace(spec.CgroupNamespace, "")
+	}
+	if cgroupMode.IsContainer() {
+		logrus.Debug("Using container cgroup mode")
+	}
+	return nil
+}
+
 func addRlimits(config *CreateConfig, g *generate.Generator) error {
 	var (
 		kernelMax  uint64 = 1048576