Merge pull request #12403 from giuseppe/improve-cgroup-detection

libpod: improve heuristic to detect cgroup

6 files changed, 59 insertions, 9 deletions

diff --git a/libpod/container.go b/libpod/container.go
index c38acb513..482af43f3 100644
--- a/libpod/container.go
+++ b/libpod/container.go
@@ -6,9 +6,11 @@ import (
 	"io/ioutil"
 	"net"
 	"os"
+	"strings"
 	"time"
 
 	types040 "github.com/containernetworking/cni/pkg/types/040"
+	"github.com/containers/common/pkg/config"
 	"github.com/containers/common/pkg/secrets"
 	"github.com/containers/image/v5/manifest"
 	"github.com/containers/podman/v3/libpod/define"
@@ -963,6 +965,29 @@ func (c *Container) cGroupPath() (string, error) {
 		return "", errors.Errorf("could not find any cgroup in %q", procPath)
 	}
 
+	cgroupManager := c.CgroupManager()
+	switch {
+	case c.config.CgroupsMode == cgroupSplit:
+		name := fmt.Sprintf("/libpod-payload-%s/", c.ID())
+		if index := strings.LastIndex(cgroupPath, name); index >= 0 {
+			return cgroupPath[:index+len(name)-1], nil
+		}
+	case cgroupManager == config.CgroupfsCgroupsManager:
+		name := fmt.Sprintf("/libpod-%s/", c.ID())
+		if index := strings.LastIndex(cgroupPath, name); index >= 0 {
+			return cgroupPath[:index+len(name)-1], nil
+		}
+	case cgroupManager == config.SystemdCgroupsManager:
+		// When running under systemd, try to detect the scope that was requested
+		// to be created.  It improves the heuristic since we report the first
+		// cgroup that was created instead of the cgroup where PID 1 might have
+		// moved to.
+		name := fmt.Sprintf("/libpod-%s.scope/", c.ID())
+		if index := strings.LastIndex(cgroupPath, name); index >= 0 {
+			return cgroupPath[:index+len(name)-1], nil
+		}
+	}
+
 	return cgroupPath, nil
 }
 
diff --git a/libpod/container_inspect.go b/libpod/container_inspect.go
index 76a08ce30..83b643266 100644
--- a/libpod/container_inspect.go
+++ b/libpod/container_inspect.go
@@ -97,6 +97,16 @@ func (c *Container) getContainerInspectData(size bool, driverData *define.Driver
 		return nil, err
 	}
 
+	cgroupPath, err := c.cGroupPath()
+	if err != nil {
+		// Handle the case where the container is not running or has no cgroup.
+		if errors.Is(err, define.ErrNoCgroups) || errors.Is(err, define.ErrCtrStopped) {
+			cgroupPath = ""
+		} else {
+			return nil, err
+		}
+	}
+
 	data := &define.InspectContainerData{
 		ID:      config.ID,
 		Created: config.CreatedTime,
@@ -116,6 +126,7 @@ func (c *Container) getContainerInspectData(size bool, driverData *define.Driver
 			StartedAt:    runtimeInfo.StartedTime,
 			FinishedAt:   runtimeInfo.FinishedTime,
 			Checkpointed: runtimeInfo.Checkpointed,
+			CgroupPath:   cgroupPath,
 		},
 		Image:           config.RootfsImageID,
 		ImageName:       config.RootfsImageName,
diff --git a/libpod/container_internal_linux.go b/libpod/container_internal_linux.go
index 364b77f29..956460c32 100644
--- a/libpod/container_internal_linux.go
+++ b/libpod/container_internal_linux.go
@@ -2618,7 +2618,7 @@ func (c *Container) getOCICgroupPath() (string, error) {
 		if err != nil {
 			return "", err
 		}
-		return filepath.Join(selfCgroup, "container"), nil
+		return filepath.Join(selfCgroup, fmt.Sprintf("libpod-payload-%s", c.ID())), nil
 	case cgroupManager == config.SystemdCgroupsManager:
 		// When the OCI runtime is set to use Systemd as a cgroup manager, it
 		// expects cgroups to be passed as follows:
diff --git a/libpod/define/container_inspect.go b/libpod/define/container_inspect.go
index 8e07cff81..677b39218 100644
--- a/libpod/define/container_inspect.go
+++ b/libpod/define/container_inspect.go
@@ -204,6 +204,7 @@ type InspectContainerState struct {
 	FinishedAt   time.Time          `json:"FinishedAt"`
 	Health       HealthCheckResults `json:"Health,omitempty"`
 	Checkpointed bool               `json:"Checkpointed,omitempty"`
+	CgroupPath   string             `json:"CgroupPath,omitempty"`
 }
 
 // Healthcheck returns the HealthCheckResults. This is used for old podman compat
diff --git a/libpod/stats.go b/libpod/stats.go
index 975152535..cc1250e83 100644
--- a/libpod/stats.go
+++ b/libpod/stats.go
@@ -3,6 +3,7 @@
 package libpod
 
 import (
+	"math"
 	"strings"
 	"syscall"
 	"time"
@@ -68,7 +69,7 @@ func (c *Container) GetContainerStats(previousStats *define.ContainerStats) (*de
 	stats.AvgCPU = calculateAvgCPU(stats.CPU, previousStats.AvgCPU, previousStats.DataPoints)
 	stats.DataPoints = previousStats.DataPoints + 1
 	stats.MemUsage = cgroupStats.Memory.Usage.Usage
-	stats.MemLimit = getMemLimit(cgroupStats.Memory.Usage.Limit)
+	stats.MemLimit = c.getMemLimit()
 	stats.MemPerc = (float64(stats.MemUsage) / float64(stats.MemLimit)) * 100
 	stats.PIDs = 0
 	if conState == define.ContainerStateRunning || conState == define.ContainerStatePaused {
@@ -91,22 +92,29 @@ func (c *Container) GetContainerStats(previousStats *define.ContainerStats) (*de
 	return stats, nil
 }
 
-// getMemory limit returns the memory limit for a given cgroup
-// If the configured memory limit is larger than the total memory on the sys, the
-// physical system memory size is returned
-func getMemLimit(cgroupLimit uint64) uint64 {
+// getMemory limit returns the memory limit for a container
+func (c *Container) getMemLimit() uint64 {
+	memLimit := uint64(math.MaxUint64)
+
+	if c.config.Spec.Linux != nil && c.config.Spec.Linux.Resources != nil &&
+		c.config.Spec.Linux.Resources.Memory != nil && c.config.Spec.Linux.Resources.Memory.Limit != nil {
+		memLimit = uint64(*c.config.Spec.Linux.Resources.Memory.Limit)
+	}
+
 	si := &syscall.Sysinfo_t{}
 	err := syscall.Sysinfo(si)
 	if err != nil {
-		return cgroupLimit
+		return memLimit
 	}
 
 	//nolint:unconvert
 	physicalLimit := uint64(si.Totalram)
-	if cgroupLimit > physicalLimit {
+
+	if memLimit <= 0 || memLimit > physicalLimit {
 		return physicalLimit
 	}
-	return cgroupLimit
+
+	return memLimit
 }
 
 // calculateCPUPercent calculates the cpu usage using the latest measurement in stats.
diff --git a/test/e2e/systemd_test.go b/test/e2e/systemd_test.go
index 98def3d8f..32c2cd1b8 100644
--- a/test/e2e/systemd_test.go
+++ b/test/e2e/systemd_test.go
@@ -109,6 +109,11 @@ WantedBy=multi-user.target
 		stats := podmanTest.Podman([]string{"stats", "--no-stream", ctrName})
 		stats.WaitWithDefaultTimeout()
 		Expect(stats).Should(Exit(0))
+
+		cgroupPath := podmanTest.Podman([]string{"inspect", "--format='{{.State.CgroupPath}}'", ctrName})
+		cgroupPath.WaitWithDefaultTimeout()
+		Expect(cgroupPath).Should(Exit(0))
+		Expect(result.OutputToString()).To(Not(ContainSubstring("init.scope")))
 	})
 
 	It("podman create container with systemd entrypoint triggers systemd mode", func() {