Add fallback for missing /proc/1/mounts (prometheus#1172)

* Add fallback for missing /proc/1/mounts On some systems, `/proc/1/mounts` is hidden from non-root users due to the `hidepid` procfs feature. Attempt to fallback to `/proc/mounts` if `/proc/1/mounts` is not found. Signed-off-by: Ben Kochie <[email protected]> * Add tests. Signed-off-by: Ben Kochie <[email protected]> * Add CHANGELOG entry. Signed-off-by: Ben Kochie <[email protected]>
agaengel · Nov 30, 2018 · 2d7cad7 · 2d7cad7
1 parent d7c41fa
commit 2d7cad7
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -5,9 +5,10 @@
 ### Changes
 
 * [BUGFIX]
-* [CHANGE]
-* [ENHANCEMENT]
-* [FEATURE]
+* [BUGFIX] Add fallback for missing /proc/1/mounts #1172
+* [CHANGE] Add TCPSynRetrans to netstat default filter #1143
+* [ENHANCEMENT] Add Infiniband counters #1120
+* [FEATURE] Add a flag to disable exporter metrics #1148
 
 ## 0.17.0-rc.0 / 2018-10-19
 

diff --git a/collector/filesystem_linux.go b/collector/filesystem_linux.go
@@ -134,6 +134,11 @@ func stuckMountWatcher(mountPoint string, success chan struct{}) {
 
 func mountPointDetails() ([]filesystemLabels, error) {
 	file, err := os.Open(procFilePath("1/mounts"))
+	if os.IsNotExist(err) {
+		// Fallback to `/proc/mounts` if `/proc/1/mounts` is missing due hidepid.
+		log.Debugf("Got %q reading root mounts, falling back to system mounts", err)
+		file, err = os.Open(procFilePath("mounts"))
+	}
 	if err != nil {
 		return nil, err
 	}

diff --git a/collector/filesystem_linux_test.go b/collector/filesystem_linux_test.go
@@ -70,3 +70,24 @@ func TestMountPointDetails(t *testing.T) {
 		}
 	}
 }
+
+func TestMountsFallback(t *testing.T) {
+	if _, err := kingpin.CommandLine.Parse([]string{"--path.procfs", "./fixtures_hidepid/proc"}); err != nil {
+		t.Fatal(err)
+	}
+
+	expected := map[string]string{
+		"/": "",
+	}
+
+	filesystems, err := mountPointDetails()
+	if err != nil {
+		t.Log(err)
+	}
+
+	for _, fs := range filesystems {
+		if _, ok := expected[fs.mountPoint]; !ok {
+			t.Errorf("Got unexpected %s", fs.mountPoint)
+		}
+	}
+}
diff --git a/collector/fixtures_hidepid/proc/mounts b/collector/fixtures_hidepid/proc/mounts
@@ -0,0 +1 @@
+rootfs / rootfs rw 0 0