Fixes cgroup ID parsing in newer docker versions (grafana#1287)

mattdurham · Oct 29, 2024 · 719b211 · 719b211
1 parent 5c93589
commit 719b211
Show file tree

Hide file tree

Showing 2 changed files with 29 additions and 20 deletions.
diff --git a/pkg/internal/helpers/container/container.go b/pkg/internal/helpers/container/container.go
@@ -24,17 +24,22 @@ type Info struct {
 	PIDNamespace uint32
 }
 
-// A docker cgroup entry is a string like - when running beyla as a process on the node:
-// 0::/docker/<hex...>/kubelet.slice/kubelet-kubepods.slice/kubelet-kubepods-besteffort.slice/kubelet-kubepods-besteffort-pod<hex...>.slice/cri-containerd-<hex...>.scope
-// where the last <hex...> chain is the container ID inside its Pod
-var dockerCgroup = regexp.MustCompile(`^\d+:.*:.*/.*-([\da-fA-F]+)\.scope`)
+var cgroupFormats = []*regexp.Regexp{
+	// 0::/docker/<hex...>/kubelet.slice/kubelet-kubepods.slice/kubelet-kubepods-besteffort.slice/kubelet-kubepods-besteffort-pod<hex...>.slice/cri-containerd-<hex...>.scope
+	// where the last <hex...> chain is the container ID inside its Pod
+	regexp.MustCompile(`^\d+:.*:.*/.*-([\da-fA-F]+)\.scope`),
 
-// A k8s cgroup entry is a string like - when running beyla as daemonset in k8s:
-// GKE: /kubepods/burstable/pod4a163a05-439d-484b-8e53-2968bc15824f/cde6dfaf5007ed65aad2d6aed72af91b0f3d95813492f773286e29ae145d20f4
-// GKE-containerd: /kubepods/burstable/podb53dfa9e2dc9b890f7fadb2770857b03/bb959773d06ad1a07d469bced637bbc49b6f8573c493fd0548d7f5810eb3e5a8
-// EKS: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-poddde1244b_5bb5_4297_b544_85f3bc0d80bf.slice/cri-containerd-acb62391578595ec849d87d8556369cee7f935f0425097fd5f870df0e8aabd3c.scope
-// Containerd: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod7260904bbd08e72e4dff95d9fccd2ee8.slice/cri-containerd-d36686f9785534531160dc936aec9d711a26eb37f4fc7752a2ae27d0a24345c1.scope
-var k8sCgroup = regexp.MustCompile(`^\d+:.*:/kubepods.*([0-9a-f]{64})`)
+	// formats for other Kubernetes distributions
+	// GKE: /kubepods/burstable/pod4a163a05-439d-484b-8e53-2968bc15824f/cde6dfaf5007ed65aad2d6aed72af91b0f3d95813492f773286e29ae145d20f4
+	// GKE-containerd: /kubepods/burstable/podb53dfa9e2dc9b890f7fadb2770857b03/bb959773d06ad1a07d469bced637bbc49b6f8573c493fd0548d7f5810eb3e5a8
+	// EKS: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-poddde1244b_5bb5_4297_b544_85f3bc0d80bf.slice/cri-containerd-acb62391578595ec849d87d8556369cee7f935f0425097fd5f870df0e8aabd3c.scope
+	// Containerd: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod7260904bbd08e72e4dff95d9fccd2ee8.slice/cri-containerd-d36686f9785534531160dc936aec9d711a26eb37f4fc7752a2ae27d0a24345c1.scope
+	regexp.MustCompile(`^\d+:.*:/kubepods.*([0-9a-f]{64})`),
+
+	// as fallback, other formats for cgroup which might appear in other Docker implementations
+	// 0::/../../pode039200acb850c82bb901653cc38ff6e/58452031ab6dcaa4fe3ff91f8a46fd41a4a2405586f3cf3d5cb9c93b5bcf62cc
+	regexp.MustCompile(`^\d+:.*:.*/.*/.*/([0-9a-fA-F]{64})`),
+}
 
 // InfoForPID returns the container ID and PID namespace for the given PID.
 func InfoForPID(pid uint32) (Info, error) {
@@ -47,21 +52,23 @@ func InfoForPID(pid uint32) (Info, error) {
 	if err != nil {
 		return Info{}, fmt.Errorf("reading %s: %w", cgroupFile, err)
 	}
-	// We look for the docker cgroup entry first, as it's the most common
+
 	for _, cgroupEntry := range bytes.Split(cgroupBytes, []byte{'\n'}) {
-		submatches := dockerCgroup.FindSubmatch(cgroupEntry)
-		if len(submatches) < 2 {
-			continue
+		if cgroupID, ok := findCgroup(string(cgroupEntry)); ok {
+			return Info{PIDNamespace: ns, ContainerID: cgroupID}, nil
 		}
-		return Info{PIDNamespace: ns, ContainerID: string(submatches[1])}, nil
 	}
-	// If we didn't find a docker entry, we look for a k8s entry
-	for _, cgroupEntry := range bytes.Split(cgroupBytes, []byte{'\n'}) {
-		submatches := k8sCgroup.FindSubmatch(cgroupEntry)
+	return Info{}, fmt.Errorf("%s: couldn't find any docker entry for process with PID %d", cgroupFile, pid)
+}
+
+// look for a cgroup ID on all the possible formats
+func findCgroup(cgroupEntry string) (string, bool) {
+	for _, re := range cgroupFormats {
+		submatches := re.FindStringSubmatch(cgroupEntry)
 		if len(submatches) < 2 {
 			continue
 		}
-		return Info{PIDNamespace: ns, ContainerID: string(submatches[1])}, nil
+		return submatches[1], true
 	}
-	return Info{}, fmt.Errorf("%s: couldn't find any docker entry for process with PID %d", cgroupFile, pid)
+	return "", false
 }
diff --git a/pkg/internal/helpers/container/container_test.go b/pkg/internal/helpers/container/container_test.go
@@ -39,6 +39,8 @@ var fixturesWithContainer = map[uint32]string{
 	788: `0::/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-poddde1244b_5bb5_4297_b544_85f3bc0d80bf.slice/cri-containerd-40c03570b6f4c30bc8d69923d37ee698f5cfcced92c7b7df1c47f6f7887378a9.scope`,
 	// Containerd cgroup entry
 	889: `0::/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod7260904bbd08e72e4dff95d9fccd2ee8.slice/cri-containerd-40c03570b6f4c30bc8d69923d37ee698f5cfcced92c7b7df1c47f6f7887378a9.scope`,
+	// Docker 27+
+	899: `0::/../../pode039200acb850c82bb901653cc38ff6e/40c03570b6f4c30bc8d69923d37ee698f5cfcced92c7b7df1c47f6f7887378a9`,
 }
 
 var fixturesWithoutContainer = map[uint32]string{