Description
What happened?
Kubelet's swap related metrics were introduced in #118865. However, these swap-related metrics are missing from /metrics/resource endpoint. Only node-level swap usage metrics are visible. The pod-level and container-level swap usage are available from /stats/summary endpoint, but no metrics are visible from /metrics/resource.
kubectl get --raw "/api/v1/nodes/<node>/proxy/metrics/resource" | grep -i swap
# HELP node_swap_usage_bytes [ALPHA] Current swap usage of the node in bytes. Reported only on non-windows systems
# TYPE node_swap_usage_bytes gauge
node_swap_usage_bytes 3.4340864e+07 1747937814848
kubectl get --raw "/api/v1/nodes/<node>//proxy/stats/summary" | jq ".pods[] | select(.swap.swapUsageBytes > 0)"
{
"podRef": {
"name": "oom-test-pod-stress-ng",
"namespace": "default",
"uid": "4bc5b67c-d750-47d4-a36a-5cec6190d752"
},
"containers": [
{
"name": "memory-eater",
# ... omitted
"swap": {
"time": "2025-05-22T18:19:01Z",
"swapAvailableBytes": 0,
"swapUsageBytes": 33554432
}
}
],
# omitted...
"swap": {
"time": "2025-05-22T18:18:50Z",
"swapUsageBytes": 33554432
}
}
What did you expect to happen?
Container-level swap usage container_swap_usage_bytes and pod-level swap usage pod_swap_usage_bytes metrics should be available from /metrics/resource endpoint.
How can we reproduce it (as minimally and precisely as possible)?
Create a node with swap enabled (https://kubernetes.io/blog/2025/03/25/swap-linux-improvements/#install-a-swap-enabled-cluster-with-kubeadm)
Get the swap metrics `kubectl get --raw "/api/v1/nodes//proxy/metrics/resource"
Anything else we need to know?
The node is using cadvisor CRI for resource metrics.
Also happened for kind: kubernetes-sigs/kind#3834
Kubernetes version
$ kubectl version
Client Version: v1.33.1
Kustomize Version: v5.6.0
Server Version: v1.33.1
$ kubelet --version
Kubernetes v1.33.1Cloud provider
OS version
# On Linux:
$ cat /etc/os-release
NAME="Container-Optimized OS"
ID=cos
PRETTY_NAME="Container-Optimized OS from Google"
HOME_URL="https://cloud.google.com/container-optimized-os/docs"
BUG_REPORT_URL="https://cloud.google.com/container-optimized-os/docs/resources/support-policy#contact_us"
GOOGLE_METRICS_PRODUCT_ID=26
KERNEL_COMMIT_ID=ce1882ff887f9f692176e3431dc39f7f79bf8c72
GOOGLE_CRASH_ID=Lakitu
VERSION=121
VERSION_ID=121
BUILD_ID=18867.90.23
$ uname -a
Linux gke-yuanwangyw-test-dev-pool-4756ad32-v354 6.6.87+ #1 SMP Sat May 10 09:40:07 UTC 2025 x86_64 INTEL(R) XEON(R) PLATINUM 8581C CPU @ 2.10GHz GenuineIntel GNU/Linux
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### Install tools
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### Container runtime (CRI) and version (if applicable)
<details>
containerd://2.0.4
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### Related plugins (CNI, CSI, ...) and versions (if applicable)
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