Red Hat Summit 红帽全球峰会支持控制台（Console）开发人员开始试用联系人

第 4 章 Working with nodes

You can list all the nodes in your cluster to obtain information such as status, age, memory usage, and details about the nodes.

When you perform node management operations, the CLI interacts with node objects that are representations of actual node hosts. The master uses the information from node objects to validate nodes with health checks.

4.1.1. About listing all the nodes in a cluster
复制链接

You can get detailed information on the nodes in the cluster.

  • The following command lists all nodes: 

    $ oc get nodes
    Copy to Clipboard Toggle word wrap

    The following example is a cluster with healthy nodes: 

    $ oc get nodes
    Copy to Clipboard Toggle word wrap

    Example output

    NAME                   STATUS    ROLES     AGE       VERSION
master.example.com     Ready     master    7h        v1.18.3
node1.example.com      Ready     worker    7h        v1.18.3
node2.example.com      Ready     worker    7h        v1.18.3
    Copy to Clipboard Toggle word wrap

    The following example is a cluster with one unhealthy node: 

    $ oc get nodes
    Copy to Clipboard Toggle word wrap

    Example output

    NAME                   STATUS                      ROLES     AGE       VERSION
master.example.com     Ready                       master    7h        v1.20.0
node1.example.com      NotReady,SchedulingDisabled worker    7h        v1.20.0
node2.example.com      Ready                       worker    7h        v1.20.0
    Copy to Clipboard Toggle word wrap

    The conditions that trigger a NotReady status are shown later in this section.

  • The -o wide option provides additional information on nodes. 

    $ oc get nodes -o wide
    Copy to Clipboard Toggle word wrap

    Example output

    NAME                STATUS   ROLES    AGE    VERSION           INTERNAL-IP    EXTERNAL-IP   OS-IMAGE                                                      KERNEL-VERSION                 CONTAINER-RUNTIME
master.example.com  Ready    master   171m   v1.20.0+39c0afe   10.0.129.108   <none>        Red Hat Enterprise Linux CoreOS 48.83.202103210901-0 (Ootpa)   4.18.0-240.15.1.el8_3.x86_64   cri-o://1.21.0-30.rhaos4.8.gitf2f339d.el8-dev
node1.example.com   Ready    worker   72m    v1.20.0+39c0afe   10.0.129.222   <none>        Red Hat Enterprise Linux CoreOS 48.83.202103210901-0 (Ootpa)   4.18.0-240.15.1.el8_3.x86_64   cri-o://1.21.0-30.rhaos4.8.gitf2f339d.el8-dev
node2.example.com   Ready    worker   164m   v1.20.0+39c0afe   10.0.142.150   <none>        Red Hat Enterprise Linux CoreOS 48.83.202103210901-0 (Ootpa)   4.18.0-240.15.1.el8_3.x86_64   cri-o://1.21.0-30.rhaos4.8.gitf2f339d.el8-dev
    Copy to Clipboard Toggle word wrap

  • The following command lists information about a single node: 

    $ oc get node <node>
    Copy to Clipboard Toggle word wrap

    For example: 

    $ oc get node node1.example.com
    Copy to Clipboard Toggle word wrap

    Example output

    NAME                   STATUS    ROLES     AGE       VERSION
node1.example.com      Ready     worker    7h        v1.20.0
    Copy to Clipboard Toggle word wrap

  • The following command provides more detailed information about a specific node, including the reason for the current condition: 

    $ oc describe node <node>
    Copy to Clipboard Toggle word wrap

    For example: 

    $ oc describe node node1.example.com
    Copy to Clipboard Toggle word wrap

    Example output

    Name:               node1.example.com
    1 
    
Roles:              worker
    2 
    
Labels:             beta.kubernetes.io/arch=amd64
    3 
    
                    beta.kubernetes.io/instance-type=m4.large
                    beta.kubernetes.io/os=linux
                    failure-domain.beta.kubernetes.io/region=us-east-2
                    failure-domain.beta.kubernetes.io/zone=us-east-2a
                    kubernetes.io/hostname=ip-10-0-140-16
                    node-role.kubernetes.io/worker=
Annotations:        cluster.k8s.io/machine: openshift-machine-api/ahardin-worker-us-east-2a-q5dzc
    4 
    
                    machineconfiguration.openshift.io/currentConfig: worker-309c228e8b3a92e2235edd544c62fea8
                    machineconfiguration.openshift.io/desiredConfig: worker-309c228e8b3a92e2235edd544c62fea8
                    machineconfiguration.openshift.io/state: Done
                    volumes.kubernetes.io/controller-managed-attach-detach: true
CreationTimestamp:  Wed, 13 Feb 2019 11:05:57 -0500
Taints:             <none>
    5 
    
Unschedulable:      false
Conditions:
    6 
    
  Type             Status  LastHeartbeatTime                 LastTransitionTime                Reason                       Message
  ----             ------  -----------------                 ------------------                ------                       -------
  OutOfDisk        False   Wed, 13 Feb 2019 15:09:42 -0500   Wed, 13 Feb 2019 11:05:57 -0500   KubeletHasSufficientDisk     kubelet has sufficient disk space available
  MemoryPressure   False   Wed, 13 Feb 2019 15:09:42 -0500   Wed, 13 Feb 2019 11:05:57 -0500   KubeletHasSufficientMemory   kubelet has sufficient memory available
  DiskPressure     False   Wed, 13 Feb 2019 15:09:42 -0500   Wed, 13 Feb 2019 11:05:57 -0500   KubeletHasNoDiskPressure     kubelet has no disk pressure
  PIDPressure      False   Wed, 13 Feb 2019 15:09:42 -0500   Wed, 13 Feb 2019 11:05:57 -0500   KubeletHasSufficientPID      kubelet has sufficient PID available
  Ready            True    Wed, 13 Feb 2019 15:09:42 -0500   Wed, 13 Feb 2019 11:07:09 -0500   KubeletReady                 kubelet is posting ready status
Addresses:
    7 
    
  InternalIP:   10.0.140.16
  InternalDNS:  ip-10-0-140-16.us-east-2.compute.internal
  Hostname:     ip-10-0-140-16.us-east-2.compute.internal
Capacity:
    8 
    
 attachable-volumes-aws-ebs:  39
 cpu:                         2
 hugepages-1Gi:               0
 hugepages-2Mi:               0
 memory:                      8172516Ki
 pods:                        250
Allocatable:
 attachable-volumes-aws-ebs:  39
 cpu:                         1500m
 hugepages-1Gi:               0
 hugepages-2Mi:               0
 memory:                      7558116Ki
 pods:                        250
System Info:
    9 
    
 Machine ID:                              63787c9534c24fde9a0cde35c13f1f66
 System UUID:                             EC22BF97-A006-4A58-6AF8-0A38DEEA122A
 Boot ID:                                 f24ad37d-2594-46b4-8830-7f7555918325
 Kernel Version:                          3.10.0-957.5.1.el7.x86_64
 OS Image:                                Red Hat Enterprise Linux CoreOS 410.8.20190520.0 (Ootpa)
 Operating System:                        linux
 Architecture:                            amd64
 Container Runtime Version:               cri-o://1.16.0-0.6.dev.rhaos4.3.git9ad059b.el8-rc2
 Kubelet Version:                         v1.18.3
 Kube-Proxy Version:                      v1.18.3
PodCIDR:                                  10.128.4.0/24
ProviderID:                               aws:///us-east-2a/i-04e87b31dc6b3e171
Non-terminated Pods:                      (13 in total)
    10 
    
  Namespace                               Name                                   CPU Requests  CPU Limits  Memory Requests  Memory Limits
  ---------                               ----                                   ------------  ----------  ---------------  -------------
  openshift-cluster-node-tuning-operator  tuned-hdl5q                            0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-dns                           dns-default-l69zr                      0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-image-registry                node-ca-9hmcg                          0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-ingress                       router-default-76455c45c-c5ptv         0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-machine-config-operator       machine-config-daemon-cvqw9            20m (1%)      0 (0%)      50Mi (0%)        0 (0%)
  openshift-marketplace                   community-operators-f67fh              0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-monitoring                    alertmanager-main-0                    50m (3%)      50m (3%)    210Mi (2%)       10Mi (0%)
  openshift-monitoring                    grafana-78765ddcc7-hnjmm               100m (6%)     200m (13%)  100Mi (1%)       200Mi (2%)
  openshift-monitoring                    node-exporter-l7q8d                    10m (0%)      20m (1%)    20Mi (0%)        40Mi (0%)
  openshift-monitoring                    prometheus-adapter-75d769c874-hvb85    0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-multus                        multus-kw8w5                           0 (0%)        0 (0%)      0 (0%)           0 (0%)
  openshift-sdn                           ovs-t4dsn                              100m (6%)     0 (0%)      300Mi (4%)       0 (0%)
  openshift-sdn                           sdn-g79hg                              100m (6%)     0 (0%)      200Mi (2%)       0 (0%)
Allocated resources:
  (Total limits may be over 100 percent, i.e., overcommitted.)
  Resource                    Requests     Limits
  --------                    --------     ------
  cpu                         380m (25%)   270m (18%)
  memory                      880Mi (11%)  250Mi (3%)
  attachable-volumes-aws-ebs  0            0
Events:
    11 
    
  Type     Reason                   Age                From                      Message
  ----     ------                   ----               ----                      -------
  Normal   NodeHasSufficientPID     6d (x5 over 6d)    kubelet, m01.example.com  Node m01.example.com status is now: NodeHasSufficientPID
  Normal   NodeAllocatableEnforced  6d                 kubelet, m01.example.com  Updated Node Allocatable limit across pods
  Normal   NodeHasSufficientMemory  6d (x6 over 6d)    kubelet, m01.example.com  Node m01.example.com status is now: NodeHasSufficientMemory
  Normal   NodeHasNoDiskPressure    6d (x6 over 6d)    kubelet, m01.example.com  Node m01.example.com status is now: NodeHasNoDiskPressure
  Normal   NodeHasSufficientDisk    6d (x6 over 6d)    kubelet, m01.example.com  Node m01.example.com status is now: NodeHasSufficientDisk
  Normal   NodeHasSufficientPID     6d                 kubelet, m01.example.com  Node m01.example.com status is now: NodeHasSufficientPID
  Normal   Starting                 6d                 kubelet, m01.example.com  Starting kubelet.
 ...
    Copy to Clipboard Toggle word wrap

    1
    The name of the node.
    2
    The role of the node, either master or worker.
    3
    The labels applied to the node.
    4
    The annotations applied to the node.
    5
    The taints applied to the node.
    6
    The node conditions and status. The conditions stanza lists the Ready, PIDPressure, PIDPressure, MemoryPressure, DiskPressure and OutOfDisk status. These condition are described later in this section.
    7
    The IP address and host name of the node.
    8
    The pod resources and allocatable resources.
    9
    Information about the node host.
    10
    The pods on the node.
    11
    The events reported by the node.

Among the information shown for nodes, the following node conditions appear in the output of the commands shown in this section:

Expand
表 4.1. Node Conditions
ConditionDescription

Ready

If true, the node is healthy and ready to accept pods. If false, the node is not healthy and is not accepting pods. If unknown, the node controller has not received a heartbeat from the node for the node-monitor-grace-period (the default is 40 seconds).

DiskPressure

If true, the disk capacity is low.

MemoryPressure

If true, the node memory is low.

PIDPressure

If true, there are too many processes on the node.

OutOfDisk

If true, the node has insufficient free space on the node for adding new pods.

NetworkUnavailable

If true, the network for the node is not correctly configured.

NotReady

If true, one of the underlying components, such as the container runtime or network, is experiencing issues or is not yet configured.

SchedulingDisabled

Pods cannot be scheduled for placement on the node.

4.1.2. Listing pods on a node in your cluster
复制链接

You can list all the pods on a specific node.

Procedure

  • To list all or selected pods on one or more nodes: 

    $ oc describe node <node1> <node2>
    Copy to Clipboard Toggle word wrap

    For example: 

    $ oc describe node ip-10-0-128-218.ec2.internal
    Copy to Clipboard Toggle word wrap

  • To list all or selected pods on selected nodes: 

    $ oc describe --selector=<node_selector>
    Copy to Clipboard Toggle word wrap 
    $ oc describe node  --selector=kubernetes.io/os
    Copy to Clipboard Toggle word wrap

    Or: 

    $ oc describe -l=<pod_selector>
    Copy to Clipboard Toggle word wrap 
    $ oc describe node -l node-role.kubernetes.io/worker
    Copy to Clipboard Toggle word wrap

  • To list all pods on a specific node, including terminated pods: 

    $ oc get pod --all-namespaces --field-selector=spec.nodeName=<nodename>
    Copy to Clipboard Toggle word wrap

You can display usage statistics about nodes, which provide the runtime environments for containers. These usage statistics include CPU, memory, and storage consumption.

Prerequisites

  • You must have cluster-reader permission to view the usage statistics.
  • Metrics must be installed to view the usage statistics.

Procedure

  • To view the usage statistics: 

    $ oc adm top nodes
    Copy to Clipboard Toggle word wrap

    Example output

    NAME                                   CPU(cores)   CPU%      MEMORY(bytes)   MEMORY%
ip-10-0-12-143.ec2.compute.internal    1503m        100%      4533Mi          61%
ip-10-0-132-16.ec2.compute.internal    76m          5%        1391Mi          18%
ip-10-0-140-137.ec2.compute.internal   398m         26%       2473Mi          33%
ip-10-0-142-44.ec2.compute.internal    656m         43%       6119Mi          82%
ip-10-0-146-165.ec2.compute.internal   188m         12%       3367Mi          45%
ip-10-0-19-62.ec2.compute.internal     896m         59%       5754Mi          77%
ip-10-0-44-193.ec2.compute.internal    632m         42%       5349Mi          72%
    Copy to Clipboard Toggle word wrap

  • To view the usage statistics for nodes with labels: 

    $ oc adm top node --selector=''
    Copy to Clipboard Toggle word wrap

    You must choose the selector (label query) to filter on. Supports =, ==, and !=.

返回顶部
Red Hat logoGithubredditYoutubeTwitter

学习

尝试、购买和销售

社区

关于红帽文档

通过我们的产品和服务，以及可以信赖的内容，帮助红帽用户创新并实现他们的目标。 了解我们当前的更新.

让开源更具包容性

红帽致力于替换我们的代码、文档和 Web 属性中存在问题的语言。欲了解更多详情，请参阅红帽博客.

關於紅帽

我们提供强化的解决方案，使企业能够更轻松地跨平台和环境（从核心数据中心到网络边缘）工作。

Theme

© 2025 Red Hat