Change:
Since upgrading from Kubernetes to we no longer get memory metrics from the endpoint on . Example: In our previous version, we would get a response like the following that included utilisation metrics: Hit the endpoint of on a cluster running version . Kubernetes version (use ): Cloud provider or hardware configuration: Provisioned on AWS with OS (e.g: ): Flatcar Container Linux by Kinvolk 2765.2.6 (Oklo) Kernel (e.g. ): 5.10.43-flatcar
/sig node
Hi AlexLastwhich container runtimes are you using? containerd?
Hi AlexLast, I have test on v1.22 with containerd, I did not reproduce this issue. If memory limit is set in the container spec of the pod, /stats/summary will report availableBytes, if memory limit is not set, /stats/summary will not be reported. just like this: ! ! code is here:
/cc We have reports of missing memory metrics on 1.20.8 and 1.21.2 now... was there a cadvisor or similar change that happened?
also /cc as an FYI
If you are using cri-o, it looks like a similar issue to and (possibly an issue with cadvisor/the way cri-o integrates with cadvisor). This would also apply to the dockershim
I'm not able to repro on GKE v1.20.8-gke.700 on containerd
Can you please provide more info about your environment, container runtime etc and possible repro steps? Thanks!
/triage needs-information
Hi, First of all, I am sorry to cut in on you. I have the same issue with Kubelet, in my case with Kubeadm. Here you are the issue: Here you are my installation: Thanks in advance
^ quick summary of the above, appears to be single-node ubuntu (not sure what kernel?) containerd 1.4.6 k8s 1.21.2 kubeadm installer
It is one node. It is only for making easier where is the problem . Kubernetes version: 1.21.2 Cloud provider or hardware configuration: Bare metal (VMware) OS: Ubuntu 18.04.5 LTS Kernel: 4.15.0-147-generic Install tools: Kubeadm Network plugin and version (if this is a network-related bug): Weave 2.8.1 CRI: Containerd 1.4.6
Sure, we're setting the following flags for : Version: We deploy our clusters using , these missing metrics are for all pods in the cluster, including pods with memory requests and limits set.
Hitting the same issue on such kind of environments Then I tested and found no issue on environment
Besides memory metrics, we noticed a loss of network in pods. I commented at the block of container and the block of pod The loss of pods occurs at the same time as loss of pods
I created cluster as follows on 1.21.2 with kubetest containerd 1.4.6 on ubuntu. This is on older version of ubuntu 18.04 LTS on kernel I don't see memory metrics being lost here.
Can we have more details on exact kernel/OS image being used here? I can't seem to repro this on 1.21.2 with same containerd/ ubuntu version as mentioned in
Hi, may I know your output of network metrics in pods?
Hi, I have tested with two kernel versions: P.S: I have just updated my in order to make easier the test. You can use it (it is necessary to install and ). Thanks in advance
We tested with two kernel versions too.
I was able to repro finally -- it looks like missing key here is that you must be using the systemd cgroup driver. With this patch and starting cluster as follows:
Hi do you mean that if using systemd cgroup driver, this issue would happen. In my environment, both containerd and kubelet are using cgroupfs driver, but the issue still exists containerd config dump
Hi, Here you are my Containerd & Kubelet config: ` As far as I know, systemd cgroup driver should be configured in order to have a proper perfomance in Kubernetes. Is it a bug with Kubelet? Thanks in advance
Hi thanks for the response, I've found the following in the , so will have a go at setting that parameter
Thanks for all the info! I was only able to repro this on systemd cgroup driver as mentioned in It did not repro for me when using cgroupfs. This will need some additional investigation to figure out the root cause and why memory metrics are not being reported correctly and see if this is a kubelet or cAdvisor issue. /cc
Hi, Thanks . By the way, there is a new issue reporting the same behaviour:
After setting kubelet's log verbosity level to 10, I found logs like Is this related? And I checked that according the log, all the pod sandboxID are missing
Thanks I was able to confirm that switching to fixed the missing metrics. From a bit of research, it's my understanding that using the driver on a node with is not recommended - can you confirm?
By stepping into the code, I found that the container info returned by this func is nil, so that the will always be false. Thus will always be . That explains the last log has expected fields. But because of 1), this func cannot be called. There's really a label-related issue on cadvisor: (Thanks With the workaround, I can recover the missed metrics
/remove-triage needs-information /triage accepted
Thanks for digging deeper into this I'm still a bit confused on the relationship between this and systemd cgroup driver. Do the labels being missing have something to do with systemd cgroup driver being used? Also are you using a different socket path for containerd i.e. not the default as mentioned in ?
We didn't use the default but used and not specified
Interesting! In the test I made in the container-runtime-endpoint is set to default (i.e. ).
With debugging, I found that on kubernetes 1.21.2 when using different cgroup driver, the cgroupPath format of containers are different. : systemd + containerd:cgroupfs : systemd + containerd: systemd : cgroupfs + containerd: cgroupfs The would return a map using the path.Base of cgroupPath Later, we use containerID to check to add metrics. So only in the third case, the key of are . That's how the cgroup driver impacts the metrics.
To sum up, and are two different cases that caused this issue. For the case, I think it's a bug we need fix: we should make sure the key of always be BTW do you know why the cgroupPath format are different when using different cgroup driver?
I believe it's expected that the cgroup naming will differ when using systemd cgroup driver vs cgroupfs. Kubelet internally has some logic for parsing and converting between the two different formats, e.g. and I left some comments on your proposed PR: Thanks for helping look into this issue!
/priority important-soon

Discussion:
if !isPodManagedContainer(&info) { continue } <del> stats[path.Base(key)] = info </del> <ins> stats[extractIDFromCgroupPath(key)] = info </ins> } return stats } <ins> func extractIDFromCgroupPath(cgroupPath string) string { // case0 == cgroupfs: "/kubepods/burstable/pod2fc932ce-fdcc-454b-97bd-aadfdeb4c340/9be25294016e2dc0340dd605ce1f57b492039b267a6a618a7ad2a7a58a740f32" id := path.Base(cgroupPath) // case1 == systemd: "/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod2fc932ce_fdcc_454b_97bd_aadfdeb4c340.slice/cri-containerd-aaefb9d8feed2d453b543f6d928cede7a4dbefa6a0ae7c9b990dd234c56e93b9.scope" // trim anything before the final '-' and suffix .scope systemdSuffix := ".scope" if strings.HasSuffix(id, systemdSuffix) { id = strings.TrimSuffix(id, systemdSuffix) components := strings.Split(id, "-") if len(components) > 1 { id = components[len(components)-1] } } return id } </ins>

"os" "path/filepath" "runtime" <ins> "strings" </ins> "testing" "time"

if terminated { p.PodSandboxStatus.State = runtimeapi.PodSandboxState_SANDBOX_NOTREADY } <del> p.PodSandboxStatus.Id = string(uuid.NewUUID()) </del> <ins> p.PodSandboxStatus.Id = strings.ReplaceAll(string(uuid.NewUUID()), "-", "") </ins> return p }

} else { c.ContainerStatus.State = runtimeapi.ContainerState_CONTAINER_RUNNING } <del> c.ContainerStatus.Id = string(uuid.NewUUID()) </del> <ins> c.ContainerStatus.Id = strings.ReplaceAll(string(uuid.NewUUID()), "-", "") </ins> return c }

assert.Equal(t, test.expected, cached, test.desc) } } <ins> func TestExtractIDFromCgroupPath(t *testing.T) { tests := []struct { cgroupPath string expected   string }{ { cgroupPath: "/kubepods/burstable/pod2fc932ce-fdcc-454b-97bd-aadfdeb4c340/9be25294016e2dc0340dd605ce1f57b492039b267a6a618a7ad2a7a58a740f32", expected:   "9be25294016e2dc0340dd605ce1f57b492039b267a6a618a7ad2a7a58a740f32", }, { cgroupPath: "/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod2fc932ce_fdcc_454b_97bd_aadfdeb4c340.slice/cri-containerd-aaefb9d8feed2d453b543f6d928cede7a4dbefa6a0ae7c9b990dd234c56e93b9.scope", expected:   "aaefb9d8feed2d453b543f6d928cede7a4dbefa6a0ae7c9b990dd234c56e93b9", }, { cgroupPath: "/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod2fc932ce_fdcc_454b_97bd_aadfdeb4c340.slice/cri-o-aaefb9d8feed2d453b543f6d928cede7a4dbefa6a0ae7c9b990dd234c56e93b9.scope", expected:   "aaefb9d8feed2d453b543f6d928cede7a4dbefa6a0ae7c9b990dd234c56e93b9", }, } for _, test := range tests { id := extractIDFromCgroupPath(test.cgroupPath) assert.Equal(t, test.expected, id) } } </ins>