$ oc get 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.
You can get detailed information on the nodes in the cluster.
The following command lists all nodes:
$ oc get nodes
The following example is a cluster with healthy nodes:
$ oc get nodes
NAME STATUS ROLES AGE VERSION
master.example.com Ready master 7h v1.30.3
node1.example.com Ready worker 7h v1.30.3
node2.example.com Ready worker 7h v1.30.3
The following example is a cluster with one unhealthy node:
$ oc get nodes
NAME STATUS ROLES AGE VERSION
master.example.com Ready master 7h v1.30.3
node1.example.com NotReady,SchedulingDisabled worker 7h v1.30.3
node2.example.com Ready worker 7h v1.30.3
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
NAME STATUS ROLES AGE VERSION INTERNAL-IP EXTERNAL-IP OS-IMAGE KERNEL-VERSION CONTAINER-RUNTIME
master.example.com Ready master 171m v1.30.3 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://1.30.3-30.rhaos4.10.gitf2f339d.el8-dev
node1.example.com Ready worker 72m v1.30.3 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://1.30.3-30.rhaos4.10.gitf2f339d.el8-dev
node2.example.com Ready worker 164m v1.30.3 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://1.30.3-30.rhaos4.10.gitf2f339d.el8-dev
The following command lists information about a single node:
$ oc get node <node>
For example:
$ oc get node node1.example.com
NAME STATUS ROLES AGE VERSION
node1.example.com Ready worker 7h v1.30.3
The following command provides more detailed information about a specific node, including the reason for the current condition:
$ oc describe node <node>
For example:
$ oc describe node node1.example.com
The following example contains some values that are specific to Red Hat OpenShift Service on AWS on AWS. |
Name: node1.example.com (1)
Roles: worker (2)
Labels: kubernetes.io/os=linux
kubernetes.io/hostname=ip-10-0-131-14
kubernetes.io/arch=amd64 (3)
node-role.kubernetes.io/worker=
node.kubernetes.io/instance-type=m4.large
node.openshift.io/os_id=rhcos
node.openshift.io/os_version=4.5
region=east
topology.kubernetes.io/region=us-east-1
topology.kubernetes.io/zone=us-east-1a
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://1.30.3-0.6.dev.rhaos4.3.git9ad059b.el8-rc2
Kubelet Version: v1.30.3
Kube-Proxy Version: v1.30.3
PodCIDR: 10.128.4.0/24
ProviderID: aws:///us-east-2a/i-04e87b31dc6b3e171
Non-terminated Pods: (12 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 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-ovn-kubernetes ovnkube-node-t4dsn 80m (0%) 0 (0%) 1630Mi (0%) 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.
#...
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 hostname 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:
Condition | Description |
---|---|
|
If |
|
If |
|
If |
|
If |
|
If |
|
If |
|
If |
|
Pods cannot be scheduled for placement on the node. |
You can list all the pods on a specific node.
To list all or selected pods on one or more nodes:
$ oc describe node <node1> <node2>
For example:
$ oc describe node ip-10-0-128-218.ec2.internal
To list all or selected pods on selected nodes:
$ oc describe node --selector=<node_selector>
$ oc describe node --selector=kubernetes.io/os
Or:
$ oc describe node -l=<pod_selector>
$ oc describe node -l node-role.kubernetes.io/worker
To list all pods on a specific node, including terminated pods:
$ oc get pod --all-namespaces --field-selector=spec.nodeName=<nodename>
You can display usage statistics about nodes, which provide the runtime environments for containers. These usage statistics include CPU, memory, and storage consumption.
You must have cluster-reader
permission to view the usage statistics.
Metrics must be installed to view the usage statistics.
To view the usage statistics:
$ oc adm top nodes
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%
To view the usage statistics for nodes with labels:
$ oc adm top node --selector=''
You must choose the selector (label query) to filter on. Supports =
, ==
, and !=
.