feature: add cgroupfs in Info API

Signed-off-by: Allen Sun <allensun.shl@alibaba-inc.com>

daemon/config/config.go

@@ -116,6 +116,14 @@ type Config struct {
 	DefaultNamespace string `json:"default-namespace,omitempty"`
 }
 
+// GetCgroupDriver gets cgroup driver used in runc.
+func (cfg *Config) GetCgroupDriver() string {
+	// current pouchd only supports directly managing cgroupfs.
+	// TODO: add 'systemd' to make systemd manage cgroupfs rather than directly using it.
+	// In the future we will support this config in the daemon configuration.
+	return "cgroupfs"
+}
+
 // Validate validates the user input config.
 func (cfg *Config) Validate() error {
 	// deduplicated elements in slice if there is any.

daemon/mgr/system.go

@@ -130,6 +130,7 @@ func (mgr *SystemManager) Info() (types.SystemInfo, error) {
 		HTTPProxy:         mgr.config.ImageProxy,
 		// HTTPSProxy: ,
 		// ID: ,
+		CgroupDriver:       mgr.config.GetCgroupDriver(),
 		Images:             int64(len(images)),
 		IndexServerAddress: "https://index.docker.io/v1/",
 		DefaultRegistry:    mgr.config.DefaultRegistry,

test/api_system_test.go

@@ -55,6 +55,7 @@ func (suite *APISystemSuite) TestInfo(c *check.C) {
 	c.Assert(got.Driver, check.Equals, "overlayfs")
 	c.Assert(got.NCPU, check.Equals, int64(runtime.NumCPU()))
 	c.Assert(got.CriEnabled, check.Equals, false)
+	c.Assert(got.CgroupDriver, check.Equals, "cgroupfs")
 
 	// Check the volume drivers
 	c.Assert(len(got.VolumeDrivers), check.Equals, 3)