Kubelet 无法获取“/system.slice/docker.service”的 cgroup 统计信息

mon*_*mon 5 systemd cgroups docker kubernetes

kubectl(CentOS 7 上的 1.8.3)错误消息的实际含义以及如何解决。任何参考以了解正在发生的事情。我想 kubelet 试图与 docker 交谈,但不知何故它没有发生,并且想知道哪些配置是相关的,什么是,从 Linux 的角度理解哪些概念/机制。

Nov 19 22:32:24 master kubelet[4425]: E1119 22:32:24.269786 4425 summary.go:92] 无法获取
“/system.slice/kubelet.service”的系统容器统计信息:无法获取 cgroup 统计信息"/system.slice/kubelet.service": 无法获得 con

11 月 19 日 22:32:24 master kubelet[4425]: E1119 22:32:24.269802 4425 summary.go:92] 无法获取“/”的系统容器统计信息system.slice/docker.service”:无法获得“/system.slice/docker.service”的 cgroup 统计信息:无法获得 conta

研究

发现相同的错误并通过更新 kubelet 的服务单元(如下所示)来遵循解决方法,但没有奏效。

/etc/systemd/system/kubelet.service

[Unit]
Description=kubelet: The Kubernetes Node Agent
Documentation=http://kubernetes.io/docs/

[Service]
ExecStart=/usr/bin/kubelet --runtime-cgroups=/systemd/system.slice --kubelet-cgroups=/systemd/system.slice
Restart=always
StartLimitInterval=0
RestartSec=10

[Install]
WantedBy=multi-user.target
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背景

按照安装 kubeadm设置 Kubernetes 集群。文档安装 Docker 中的部分说明了如何对齐 cgroup 驱动程序,如下所示。

注意:请确保 kubelet 使用的 cgroup 驱动程序与 Docker 使用的相同。为了确保兼容性,您可以更新 Docker,如下所示:

cat << EOF > /etc/docker/daemon.json
{
  "exec-opts": ["native.cgroupdriver=systemd"]
}
EOF
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但是这样做导致docker服务无法启动:

无法使用文件 /etc/docker/daemon.json 配置 Docker 守护进程:以下指令均指定为标志”
。11 月 19 日 16:55:56 localhost.localdomain systemd 1:docker.service:主进程退出,代码= 退出,状态 = 1/失败。

Maser 节点已准备就绪,所有系统 pod 都在运行。

$ kubectl get pods --all-namespaces
NAMESPACE     NAME                             READY     STATUS    RESTARTS   AGE
kube-system   etcd-master                      1/1       Running   0          39m
kube-system   kube-apiserver-master            1/1       Running   0          39m
kube-system   kube-controller-manager-master   1/1       Running   0          39m
kube-system   kube-dns-545bc4bfd4-mqqqk        3/3       Running   0          40m
kube-system   kube-flannel-ds-fclcs            1/1       Running   2          13m
kube-system   kube-flannel-ds-hqlnb            1/1       Running   0          39m
kube-system   kube-proxy-t7z5w                 1/1       Running   0          40m
kube-system   kube-proxy-xdw42                 1/1       Running   0          13m
kube-system   kube-scheduler-master            1/1       Running   0          39m
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环境

CentOS 上的 Kubernetes 1.8.3 和 Flannel。

$ kubectl version -o json | python -m json.tool
{
    "clientVersion": {
        "buildDate": "2017-11-08T18:39:33Z",
        "compiler": "gc",
        "gitCommit": "f0efb3cb883751c5ffdbe6d515f3cb4fbe7b7acd",
        "gitTreeState": "clean",
        "gitVersion": "v1.8.3",
        "goVersion": "go1.8.3",
        "major": "1",
        "minor": "8",
        "platform": "linux/amd64"
    },
    "serverVersion": {
        "buildDate": "2017-11-08T18:27:48Z",
        "compiler": "gc",
        "gitCommit": "f0efb3cb883751c5ffdbe6d515f3cb4fbe7b7acd",
        "gitTreeState": "clean",
        "gitVersion": "v1.8.3",
        "goVersion": "go1.8.3",
        "major": "1",
        "minor": "8",
        "platform": "linux/amd64"
    }
}


$ kubectl describe node master
Name:               master
Roles:              master
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    kubernetes.io/hostname=master
                    node-role.kubernetes.io/master=
Annotations:        flannel.alpha.coreos.com/backend-data={"VtepMAC":"86:b6:7a:d6:7b:b3"}
                    flannel.alpha.coreos.com/backend-type=vxlan
                    flannel.alpha.coreos.com/kube-subnet-manager=true
                    flannel.alpha.coreos.com/public-ip=10.0.2.15
                    node.alpha.kubernetes.io/ttl=0
                    volumes.kubernetes.io/controller-managed-attach-detach=true
Taints:             node-role.kubernetes.io/master:NoSchedule
CreationTimestamp:  Sun, 19 Nov 2017 22:27:17 +1100
Conditions:
  Type             Status  LastHeartbeatTime                 LastTransitionTime                Reason                       Message
  ----             ------  -----------------                 ------------------                ------                       -------
  OutOfDisk        False   Sun, 19 Nov 2017 23:04:56 +1100   Sun, 19 Nov 2017 22:27:13 +1100   KubeletHasSufficientDisk     kubelet has sufficient disk space available
  MemoryPressure   False   Sun, 19 Nov 2017 23:04:56 +1100   Sun, 19 Nov 2017 22:27:13 +1100   KubeletHasSufficientMemory   kubelet has sufficient memory available
  DiskPressure     False   Sun, 19 Nov 2017 23:04:56 +1100   Sun, 19 Nov 2017 22:27:13 +1100   KubeletHasNoDiskPressure     kubelet has no disk pressure
  Ready            True    Sun, 19 Nov 2017 23:04:56 +1100   Sun, 19 Nov 2017 22:32:24 +1100   KubeletReady                 kubelet is posting ready status
Addresses:
  InternalIP:  192.168.99.10
  Hostname:    master
Capacity:
 cpu:     1
 memory:  3881880Ki
 pods:    110
Allocatable:
 cpu:     1
 memory:  3779480Ki
 pods:    110
System Info:
 Machine ID:                 ca0a351004604dd49e43f8a6258ddd77
 System UUID:                CA0A3510-0460-4DD4-9E43-F8A6258DDD77
 Boot ID:                    e9060efa-42be-498d-8cb8-8b785b51b247
 Kernel Version:             3.10.0-693.el7.x86_64
 OS Image:                   CentOS Linux 7 (Core)
 Operating System:           linux
 Architecture:               amd64
 Container Runtime Version:  docker://1.12.6
 Kubelet Version:            v1.8.3
 Kube-Proxy Version:         v1.8.3
PodCIDR:                     10.244.0.0/24
ExternalID:                  master
Non-terminated Pods:         (7 in total)
  Namespace                  Name                              CPU Requests  CPU Limits  Memory Requests  Memory Limits
  ---------                  ----                              ------------  ----------  ---------------  -------------
  kube-system                etcd-master                       0 (0%)        0 (0%)      0 (0%)           0 (0%)
  kube-system                kube-apiserver-master             250m (25%)    0 (0%)      0 (0%)           0 (0%)
  kube-system                kube-controller-manager-master    200m (20%)    0 (0%)      0 (0%)           0 (0%)
  kube-system                kube-dns-545bc4bfd4-mqqqk         260m (26%)    0 (0%)      110Mi (2%)       170Mi (4%)
  kube-system                kube-flannel-ds-hqlnb             0 (0%)        0 (0%)      0 (0%)           0 (0%)
  kube-system                kube-proxy-t7z5w                  0 (0%)        0 (0%)      0 (0%)           0 (0%)
  kube-system                kube-scheduler-master             100m (10%)    0 (0%)      0 (0%)           0 (0%)
Allocated resources:
  (Total limits may be over 100 percent, i.e., overcommitted.)
  CPU Requests  CPU Limits  Memory Requests  Memory Limits
  ------------  ----------  ---------------  -------------
  810m (81%)    0 (0%)      110Mi (2%)       170Mi (4%)
Events:
  Type    Reason                   Age                From                Message
  ----    ------                   ----               ----                -------
  Normal  Starting                 38m                kubelet, master     Starting kubelet.
  Normal  NodeAllocatableEnforced  38m                kubelet, master     Updated Node Allocatable limit across pods
  Normal  NodeHasSufficientDisk    37m (x8 over 38m)  kubelet, master     Node master status is now: NodeHasSufficientDisk
  Normal  NodeHasSufficientMemory  37m (x8 over 38m)  kubelet, master     Node master status is now: NodeHasSufficientMemory
  Normal  NodeHasNoDiskPressure    37m (x7 over 38m)  kubelet, master     Node master status is now: NodeHasNoDiskPressure
  Normal  Starting                 37m                kube-proxy, master  Starting kube-proxy.
  Normal  Starting                 32m                kubelet, master     Starting kubelet.
  Normal  NodeAllocatableEnforced  32m                kubelet, master     Updated Node Allocatable limit across pods
  Normal  NodeHasSufficientDisk    32m                kubelet, master     Node master status is now: NodeHasSufficientDisk
  Normal  NodeHasSufficientMemory  32m                kubelet, master     Node master status is now: NodeHasSufficientMemory
  Normal  NodeHasNoDiskPressure    32m                kubelet, master     Node master status is now: NodeHasNoDiskPressure
  Normal  NodeNotReady             32m                kubelet, master     Node master status is now: NodeNotReady
  Normal  NodeReady                32m                kubelet, master     Node master status is now: NodeReady
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