feat: add mount option filtering to disk plugin

etc/telegraf.conf

@@ -3166,6 +3166,9 @@
   ## Ignore mount points by filesystem type.
   ignore_fs = ["tmpfs", "devtmpfs", "devfs", "iso9660", "overlay", "aufs", "squashfs"]
 
+  ## Ignore mount points by mount options.
+  ignore_mount_opts = ["bind"]
+
 
 # Read metrics about disk IO by device
 [[inputs.diskio]]

plugins/inputs/disk/README.md

@@ -17,6 +17,9 @@ Note that `used_percent` is calculated by doing `used / (used + free)`, _not_
 
   ## Ignore mount points by filesystem type.
   ignore_fs = ["tmpfs", "devtmpfs", "devfs", "iso9660", "overlay", "aufs", "squashfs"]
+
+  ## Ignore mount points by mount options.
+  ignore_mount_opts = ["bind"]
 ```
 
 ### Docker container

plugins/inputs/disk/disk.go

@@ -15,8 +15,9 @@ type DiskStats struct {
 	// Legacy support
 	LegacyMountPoints []string `toml:"mountpoints"`
 
-	MountPoints []string `toml:"mount_points"`
-	IgnoreFS    []string `toml:"ignore_fs"`
+	MountPoints     []string `toml:"mount_points"`
+	IgnoreFS        []string `toml:"ignore_fs"`
+	IgnoreMountOpts []string `toml:"ignore_mount_opts"`
 
 	Log telegraf.Logger `toml:"-"`
 }
@@ -35,7 +36,7 @@ func (ds *DiskStats) Init() error {
 }
 
 func (ds *DiskStats) Gather(acc telegraf.Accumulator) error {
-	disks, partitions, err := ds.ps.DiskUsage(ds.MountPoints, ds.IgnoreFS)
+	disks, partitions, err := ds.ps.DiskUsage(ds.MountPoints, ds.IgnoreMountOpts, ds.IgnoreFS)
 	if err != nil {
 		return fmt.Errorf("error getting disk usage info: %s", err)
 	}

plugins/inputs/disk/disk_test.go

@@ -43,6 +43,12 @@ func TestDiskUsage(t *testing.T) {
 			Fstype:     "ext4",
 			Opts:       []string{"rw", "noatime", "nodiratime", "errors=remount-ro"},
 		},
+		{
+			Device:     "/dev/sda",
+			Mountpoint: "/var/rootbind",
+			Fstype:     "ext4",
+			Opts:       []string{"ro", "noatime", "nodiratime", "bind"},
+		},
 	}
 	duAll := []diskUtil.UsageStat{
 		{
@@ -65,18 +71,29 @@ func TestDiskUsage(t *testing.T) {
 			InodesFree:  468,
 			InodesUsed:  2000,
 		},
+		{
+			Path:        "/var/rootbind",
+			Fstype:      "ext4",
+			Total:       128,
+			Free:        23,
+			Used:        100,
+			InodesTotal: 1234,
+			InodesFree:  234,
+			InodesUsed:  1000,
+		},
 	}
 
 	mps.On("Partitions", true).Return(psAll, nil)
 	mps.On("OSGetenv", "HOST_MOUNT_PREFIX").Return("")
 	mps.On("PSDiskUsage", "/").Return(&duAll[0], nil)
 	mps.On("PSDiskUsage", "/home").Return(&duAll[1], nil)
+	mps.On("PSDiskUsage", "/var/rootbind").Return(&duAll[2], nil)
 
 	err = (&DiskStats{ps: mps}).Gather(&acc)
 	require.NoError(t, err)
 
 	numDiskMetrics := acc.NFields()
-	expectedAllDiskMetrics := 14
+	expectedAllDiskMetrics := 21
 	require.Equal(t, expectedAllDiskMetrics, numDiskMetrics)
 
 	tags1 := map[string]string{
@@ -91,6 +108,12 @@ func TestDiskUsage(t *testing.T) {
 		"device": "sdb",
 		"mode":   "rw",
 	}
+	tags3 := map[string]string{
+		"path":   fmt.Sprintf("%cvar%crootbind", os.PathSeparator, os.PathSeparator),
+		"fstype": "ext4",
+		"device": "sda",
+		"mode":   "ro",
+	}
 
 	fields1 := map[string]interface{}{
 		"total":        uint64(128),
@@ -110,20 +133,35 @@ func TestDiskUsage(t *testing.T) {
 		"inodes_used":  uint64(2000),
 		"used_percent": float64(81.30081300813008),
 	}
+	fields3 := map[string]interface{}{
+		"total":        uint64(128),
+		"used":         uint64(100),
+		"free":         uint64(23),
+		"inodes_total": uint64(1234),
+		"inodes_free":  uint64(234),
+		"inodes_used":  uint64(1000),
+		"used_percent": float64(81.30081300813008),
+	}
 	acc.AssertContainsTaggedFields(t, "disk", fields1, tags1)
 	acc.AssertContainsTaggedFields(t, "disk", fields2, tags2)
+	acc.AssertContainsTaggedFields(t, "disk", fields3, tags3)
 
-	// We expect 6 more DiskMetrics to show up with an explicit match on "/"
+	// We expect 7 more DiskMetrics to show up with an explicit match on "/"
 	// and /home not matching the /dev in MountPoints
 	err = (&DiskStats{ps: &mps, MountPoints: []string{"/", "/dev"}}).Gather(&acc)
 	require.NoError(t, err)
 	require.Equal(t, expectedAllDiskMetrics+7, acc.NFields())
 
 	// We should see all the diskpoints as MountPoints includes both
-	// / and /home
-	err = (&DiskStats{ps: &mps, MountPoints: []string{"/", "/home"}}).Gather(&acc)
+	// /, /home, and /var/rootbind
+	err = (&DiskStats{ps: &mps, MountPoints: []string{"/", "/home", "/var/rootbind"}}).Gather(&acc)
 	require.NoError(t, err)
-	require.Equal(t, 2*expectedAllDiskMetrics+7, acc.NFields())
+	require.Equal(t, expectedAllDiskMetrics+7*4, acc.NFields())
+
+	// We should see all the mounts as MountPoints except the bind mound
+	err = (&DiskStats{ps: &mps, IgnoreMountOpts: []string{"bind"}}).Gather(&acc)
+	require.NoError(t, err)
+	require.Equal(t, expectedAllDiskMetrics+7*6, acc.NFields())
 }
 
 func TestDiskUsageHostMountPrefix(t *testing.T) {
@@ -287,8 +325,18 @@ func TestDiskStats(t *testing.T) {
 			InodesFree:  468,
 			InodesUsed:  2000,
 		},
+		{
+			Path:        "/var/rootbind",
+			Fstype:      "ext4",
+			Total:       128,
+			Free:        23,
+			Used:        100,
+			InodesTotal: 1234,
+			InodesFree:  234,
+			InodesUsed:  1000,
+		},
 	}
-	duFiltered := []*diskUtil.UsageStat{
+	duMountFiltered := []*diskUtil.UsageStat{
 		{
 			Path:        "/",
 			Fstype:      "ext4",
@@ -300,6 +348,28 @@ func TestDiskStats(t *testing.T) {
 			InodesUsed:  1000,
 		},
 	}
+	duOptFiltered := []*diskUtil.UsageStat{
+		{
+			Path:        "/",
+			Fstype:      "ext4",
+			Total:       128,
+			Free:        23,
+			Used:        100,
+			InodesTotal: 1234,
+			InodesFree:  234,
+			InodesUsed:  1000,
+		},
+		{
+			Path:        "/home",
+			Fstype:      "ext4",
+			Total:       256,
+			Free:        46,
+			Used:        200,
+			InodesTotal: 2468,
+			InodesFree:  468,
+			InodesUsed:  2000,
+		},
+	}
 
 	psAll := []*diskUtil.PartitionStat{
 		{
@@ -314,26 +384,47 @@ func TestDiskStats(t *testing.T) {
 			Fstype:     "ext4",
 			Opts:       []string{"rw", "noatime", "nodiratime", "errors=remount-ro"},
 		},
+		{
+			Device:     "/dev/sda",
+			Mountpoint: "/var/rootbind",
+			Fstype:     "ext4",
+			Opts:       []string{"ro", "noatime", "nodiratime", "bind"},
+		},
 	}
 
-	psFiltered := []*diskUtil.PartitionStat{
+	psMountFiltered := []*diskUtil.PartitionStat{
 		{
 			Device:     "/dev/sda",
 			Mountpoint: "/",
 			Fstype:     "ext4",
 			Opts:       []string{"ro", "noatime", "nodiratime"},
 		},
 	}
+	psOptFiltered := []*diskUtil.PartitionStat{
+		{
+			Device:     "/dev/sda",
+			Mountpoint: "/",
+			Fstype:     "ext4",
+			Opts:       []string{"ro", "noatime", "nodiratime"},
+		},
+		{
+			Device:     "/dev/sdb",
+			Mountpoint: "/home",
+			Fstype:     "ext4",
+			Opts:       []string{"rw", "noatime", "nodiratime", "errors=remount-ro"},
+		},
+	}
 
-	mps.On("DiskUsage", []string(nil), []string(nil)).Return(duAll, psAll, nil)
-	mps.On("DiskUsage", []string{"/", "/dev"}, []string(nil)).Return(duFiltered, psFiltered, nil)
-	mps.On("DiskUsage", []string{"/", "/home"}, []string(nil)).Return(duAll, psAll, nil)
+	mps.On("DiskUsage", []string(nil), []string(nil), []string(nil)).Return(duAll, psAll, nil)
+	mps.On("DiskUsage", []string{"/", "/dev"}, []string(nil), []string(nil)).Return(duMountFiltered, psMountFiltered, nil)
+	mps.On("DiskUsage", []string{"/", "/home", "/var/rootbind"}, []string(nil), []string(nil)).Return(duAll, psAll, nil)
+	mps.On("DiskUsage", []string(nil), []string{"bind"}, []string(nil)).Return(duOptFiltered, psOptFiltered, nil)
 
 	err = (&DiskStats{ps: &mps}).Gather(&acc)
 	require.NoError(t, err)
 
 	numDiskMetrics := acc.NFields()
-	expectedAllDiskMetrics := 14
+	expectedAllDiskMetrics := 21
 	require.Equal(t, expectedAllDiskMetrics, numDiskMetrics)
 
 	tags1 := map[string]string{
@@ -370,17 +461,22 @@ func TestDiskStats(t *testing.T) {
 	acc.AssertContainsTaggedFields(t, "disk", fields1, tags1)
 	acc.AssertContainsTaggedFields(t, "disk", fields2, tags2)
 
-	// We expect 6 more DiskMetrics to show up with an explicit match on "/"
-	// and /home not matching the /dev in MountPoints
+	// We expect 7 more DiskMetrics to show up with an explicit match on "/"
+	// and /home and /var/rootbind not matching the /dev in MountPoints
 	err = (&DiskStats{ps: &mps, MountPoints: []string{"/", "/dev"}}).Gather(&acc)
 	require.NoError(t, err)
 	require.Equal(t, expectedAllDiskMetrics+7, acc.NFields())
 
 	// We should see all the diskpoints as MountPoints includes both
-	// / and /home
-	err = (&DiskStats{ps: &mps, MountPoints: []string{"/", "/home"}}).Gather(&acc)
+	// /, /home, and /var/rootbind
+	err = (&DiskStats{ps: &mps, MountPoints: []string{"/", "/home", "/var/rootbind"}}).Gather(&acc)
+	require.NoError(t, err)
+	require.Equal(t, expectedAllDiskMetrics+7*4, acc.NFields())
+
+	// We should see all the mounts as MountPoints except the bind mound
+	err = (&DiskStats{ps: &mps, IgnoreMountOpts: []string{"bind"}}).Gather(&acc)
 	require.NoError(t, err)
-	require.Equal(t, 2*expectedAllDiskMetrics+7, acc.NFields())
+	require.Equal(t, expectedAllDiskMetrics+7*6, acc.NFields())
 }
 
 func TestDiskUsageIssues(t *testing.T) {

plugins/inputs/system/mock_PS.go

@@ -46,8 +46,8 @@ func (m *MockPS) CPUTimes(_, _ bool) ([]cpu.TimesStat, error) {
 	return r0, r1
 }
 
-func (m *MockPS) DiskUsage(mountPointFilter []string, fstypeExclude []string) ([]*disk.UsageStat, []*disk.PartitionStat, error) {
-	ret := m.Called(mountPointFilter, fstypeExclude)
+func (m *MockPS) DiskUsage(mountPointFilter []string, mountOptsExclude []string, fstypeExclude []string) ([]*disk.UsageStat, []*disk.PartitionStat, error) {
+	ret := m.Called(mountPointFilter, mountOptsExclude, fstypeExclude)
 
 	r0 := ret.Get(0).([]*disk.UsageStat)
 	r1 := ret.Get(1).([]*disk.PartitionStat)

plugins/inputs/system/ps.go

@@ -17,7 +17,7 @@ import (
 
 type PS interface {
 	CPUTimes(perCPU, totalCPU bool) ([]cpu.TimesStat, error)
-	DiskUsage(mountPointFilter []string, fstypeExclude []string) ([]*disk.UsageStat, []*disk.PartitionStat, error)
+	DiskUsage(mountPointFilter []string, mountOptsExclude []string, fstypeExclude []string) ([]*disk.UsageStat, []*disk.PartitionStat, error)
 	NetIO() ([]net.IOCountersStat, error)
 	NetProto() ([]net.ProtoCountersStat, error)
 	DiskIO(names []string) (map[string]disk.IOCountersStat, error)
@@ -91,6 +91,7 @@ func newSet() *set {
 
 func (s *SystemPS) DiskUsage(
 	mountPointFilter []string,
+	mountOptsExclude []string,
 	fstypeExclude []string,
 ) ([]*disk.UsageStat, []*disk.PartitionStat, error) {
 	parts, err := s.Partitions(true)
@@ -102,6 +103,10 @@ func (s *SystemPS) DiskUsage(
 	for _, filter := range mountPointFilter {
 		mountPointFilterSet.add(filter)
 	}
+	mountOptFilterSet := newSet()
+	for _, filter := range mountOptsExclude {
+		mountOptFilterSet.add(filter)
+	}
 	fstypeExcludeSet := newSet()
 	for _, filter := range fstypeExclude {
 		fstypeExcludeSet.add(filter)
@@ -120,9 +125,15 @@ func (s *SystemPS) DiskUsage(
 	var partitions []*disk.PartitionStat
 	hostMountPrefix := s.OSGetenv("HOST_MOUNT_PREFIX")
 
+partitionRange:
 	for i := range parts {
 		p := parts[i]
 
+		for _, o := range p.Opts {
+			if !mountOptFilterSet.empty() && mountOptFilterSet.has(o) {
+				continue partitionRange
+			}
+		}
 		// If there is a filter set and if the mount point is not a
 		// member of the filter set, don't gather info on it.
 		if !mountPointFilterSet.empty() && !mountPointFilterSet.has(p.Mountpoint) {