Fix docker on Centos 7

docker/docker_linux.go

@@ -46,9 +46,13 @@ func CgroupCPU(containerid string, base string) (*cpu.CPUTimesStat, error) {
 	if len(base) == 0 {
 		base = "/sys/fs/cgroup/cpuacct/docker"
 	}
-	path := path.Join(base, containerid, "cpuacct.stat")
+	statfile := path.Join(base, containerid, "cpuacct.stat")
 
-	lines, err := common.ReadLines(path)
+        if _, err := os.Stat(statfile); os.IsNotExist(err) {
+            statfile = path.Join("/sys/fs/cgroup/cpuacct/system.slice",  "docker-" + containerid + ".scope", "cpuacct.stat")
+        }
+
+	lines, err := common.ReadLines(statfile)
 	if err != nil {
 		return nil, err
 	}
@@ -84,12 +88,17 @@ func CgroupMem(containerid string, base string) (*CgroupMemStat, error) {
 	if len(base) == 0 {
 		base = "/sys/fs/cgroup/memory/docker"
 	}
-	path := path.Join(base, containerid, "memory.stat")
+	statfile := path.Join(base, containerid, "memory.stat")
+
+        if _, err := os.Stat(statfile); os.IsNotExist(err) {
+            statfile = path.Join("/sys/fs/cgroup/memory/system.slice",  "docker-" + containerid + ".scope", "memory.stat")
+        }
+
 	// empty containerid means all cgroup
 	if len(containerid) == 0 {
 		containerid = "all"
 	}
-	lines, err := common.ReadLines(path)
+	lines, err := common.ReadLines(statfile)
 	if err != nil {
 		return nil, err
 	}