List All Pods and Nodes in Kubernetes

In Kubernetes, managing and monitoring your cluster often involves interacting with the resources it manages, particularly Pods and Nodes. Pods are the smallest deployable units in Kubernetes, consisting of one or more containers that share storage and network resources. Nodes, on the other hand, are the worker machines (physical or virtual) where Pods are deployed.

This guide will walk you through the commands to list all Pods and Nodes in a Kubernetes cluster and briefly cover how to get detailed information about a specific Pod.

Listing All Pods

Pods are a critical resource in Kubernetes, representing the deployment of your application containers.

To list all Pods in your cluster, you can use the kubectl get pods command.

1. List Pods in the Default Namespace

By default, Kubernetes organizes resources into namespaces. If you don't specify a namespace, kubectl assumes the default namespace.

kubectl get pods

This command lists all Pods in the default namespace. The output will include the Pod's name, ready status, status, restarts, and age.

NAME                             READY   STATUS    RESTARTS   AGE
nginx-deployment-54f57cf6b7-x9t4x   1/1     Running   0          5m
nginx-deployment-54f57cf6b7-z8v4j   1/1     Running   0          5m

2. List Pods in All Namespaces

To get a comprehensive view of all Pods across all namespaces, use the --all-namespaces or -A flag:

kubectl get pods --all-namespaces

This command is particularly useful for administrators who need to monitor the entire cluster's state.

NAMESPACE     NAME                              READY   STATUS    RESTARTS   AGE
default       nginx-deployment-54f57cf6b7-x9t4x   1/1     Running   0          5m
default       nginx-deployment-54f57cf6b7-z8v4j   1/1     Running   0          5m
kube-system   coredns-558bd4d5db-h7v5n            1/1     Running   0          15d
kube-system   etcd-minikube                       1/1     Running   0          15d

3. List Pods with Detailed Information

To get more detailed information about each Pod, including the node it is running on and the IP addresses, use the -o wide option:

kubectl get pods -o wide

Output.

NAME                             READY   STATUS    RESTARTS   AGE   IP            NODE       NOMINATED NODE   READINESS GATES
nginx-deployment-54f57cf6b7-x9t4x   1/1     Running   0          5m    172.17.0.4   minikube   <none>           <none>
nginx-deployment-54f57cf6b7-z8v4j   1/1     Running   0          5m    172.17.0.5   minikube   <none>           <none>

4. Filtering Pods by Labels

Labels are key-value pairs attached to Kubernetes objects. You can filter Pods based on these labels using the -l flag:

kubectl get pods -l app=my-app

This command lists all Pods with the label app=my-app.

NAME                      READY   STATUS    RESTARTS   AGE
my-app-7f94987d5c-n8qlm   1/1     Running   0          10m
my-app-7f94987d5c-x9c8f   1/1     Running   0          10m

5. Getting Details of a Specific Pod

Sometimes, you need to delve deeper into a specific Pod's status and configuration. The kubectl describe pod command provides detailed information about a particular Pod, including events, conditions, and container statuses.

kubectl describe pod nginx-pod

This will gives you detail information about nginx-pod. This command is useful for troubleshooting and understanding the Pod's lifecycle.

Name:         nginx-pod
Namespace:    default
Priority:     0
Node:         worker-node/192.168.1.11
Start Time:   Thu, 22 Jul 2024 08:30:00 +0000
Labels:       app=nginx
Annotations:  <none>
Status:       Running
IP:           10.244.1.5
IPs:
  IP:  10.244.1.5
Containers:
  nginx:
    Container ID:   docker://1234567890abcdef
    Image:          nginx:1.21
    Image ID:       docker-pullable://nginx@sha256:abcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890
    Port:           80/TCP
    Host Port:      0/TCP
    State:          Running
      Started:      Thu, 22 Jul 2024 08:30:10 +0000
    Ready:          True
    Restart Count:  0
    Limits:
      cpu:     500m
      memory:  128Mi
    Requests:
      cpu:     250m
      memory:  64Mi
    Liveness:  http-get http://:80/ delay=30s timeout=1s period=10s #success=1 #failure=3
    Readiness: http-get http://:80/ delay=5s timeout=1s period=10s #success=1 #failure=3
    Environment:  <none>
    Mounts:
      /var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-f4k2j (ro)
Conditions:
  Type              Status
  Initialized       True 
  Ready             True 
  ContainersReady   True 
  PodScheduled      True 
Volumes:
  kube-api-access-f4k2j:
    Type:                    Projected (a volume that contains injected data from multiple sources)
    TokenExpirationSeconds:  3607
    ConfigMapName:           kube-root-ca.crt
    ConfigMapOptional:       <nil>
    DownwardAPI:             true
QoS Class:                   Burstable
Node-Selectors:              <none>
Tolerations:                 node.kubernetes.io/not-ready:NoExecute for 300s
                             node.kubernetes.io/unreachable:NoExecute for 300s
Events:
  Type    Reason     Age   From               Message
  ----    ------     ----  ----               -------
  Normal  Scheduled  1m    default-scheduler  Successfully assigned default/nginx-pod to worker-node
  Normal  Pulling    1m    kubelet            Pulling image "nginx:1.21"
  Normal  Pulled     1m    kubelet            Successfully pulled image "nginx:1.21" in 20s
  Normal  Created    1m    kubelet            Created container nginx
  Normal  Started    1m    kubelet            Started container nginx

Listing All Nodes

Nodes are the machines in your Kubernetes cluster that run your applications. Each Node contains the services necessary to run Pods, such as the container runtime and kubelet.

1. List Nodes

To list all Nodes in your cluster, use the kubectl get nodes command:

kubectl get nodes

This command provides information about each Node, including its name, status, roles, version, and more.

NAME       STATUS   ROLES    AGE   VERSION
minikube   Ready    master   15d   v1.20.2

2. Detailed Node Information

For a more detailed view of each Node, including their labels and resource capacity, use the -o wide option:

kubectl get nodes -o wide

This will includes additional details such as the internal IP address and the operating system of each Node.

NAME       STATUS   ROLES    AGE   VERSION   INTERNAL-IP   EXTERNAL-IP   OS-IMAGE             KERNEL-VERSION     CONTAINER-RUNTIME
minikube   Ready    master   15d   v1.20.2   192.168.49.2   <none>        Ubuntu 20.04.1 LTS   5.4.0-66-generic   docker://20.10.2

3. Node Descriptions

To get a complete description of a specific Node, including all its metadata, status, and allocated resources, use the following command:

kubectl describe node app-node

This will provides detailed information about the node named app-node in the Kubernetes cluster.

Name:               app-node
Roles:              <none>
Labels:             beta.kubernetes.io/arch=amd64
                    beta.kubernetes.io/os=linux
                    kubernetes.io/hostname=app-node
                    node-role.kubernetes.io/app=app
Annotations:        flannel.alpha.coreos.com/backend-data: {"VtepMAC":"aa:bb:cc:dd:ee:ff"}
                    flannel.alpha.coreos.com/backend-type: vxlan
                    flannel.alpha.coreos.com/public-ip: 192.168.1.10
CreationTimestamp:  Wed, 21 Jul 2024 15:30:00 +0000
Taints:             <none>
Unschedulable:      false
Lease:
  HolderIdentity:  app-node
  AcquireTime:     <unset>
  RenewTime:       Thu, 22 Jul 2024 10:00:00 +0000
Conditions:
  Type             Status  LastHeartbeatTime                 LastTransitionTime                Reason                        Message
  ----             ------  -----------------                 ------------------                ------                        -------
  MemoryPressure   False   Thu, 22 Jul 2024 10:00:00 +0000   Wed, 21 Jul 2024 15:30:00 +0000   KubeletHasSufficientMemory    kubelet has sufficient memory available
  DiskPressure     False   Thu, 22 Jul 2024 10:00:00 +0000   Wed, 21 Jul 2024 15:30:00 +0000   KubeletHasNoDiskPressure      kubelet has no disk pressure
  PIDPressure      False   Thu, 22 Jul 2024 10:00:00 +0000   Wed, 21 Jul 2024 15:30:00 +0000   KubeletHasSufficientPID       kubelet has sufficient PID available
  Ready            True    Thu, 22 Jul 2024 10:00:00 +0000   Wed, 21 Jul 2024 15:30:00 +0000   KubeletReady                  kubelet is posting ready status
Addresses:
  InternalIP:  192.168.1.10
  Hostname:    app-node
Capacity:
  cpu:                4
  ephemeral-storage:  50Gi
  hugepages-1Gi:      0
  hugepages-2Mi:      0
  memory:             16Gi
  pods:               110
Allocatable:
  cpu:                4
  ephemeral-storage:  45Gi
  hugepages-1Gi:      0
  hugepages-2Mi:      0
  memory:             15Gi
  pods:               110
System Info:
  Machine ID:                 123456789abcdef
  System UUID:                12345678-1234-1234-1234-123456789abc
  Boot ID:                    1234abcd-1234-abcd-1234-abcd1234abcd
  Kernel Version:             5.10.0-1049-azure
  OS Image:                   Ubuntu 20.04.2 LTS
  Operating System:           linux
  Architecture:               amd64
  Container Runtime Version:  docker://20.10.7
  Kubelet Version:            v1.21.1
  Kube-Proxy Version:         v1.21.1
PodCIDR:                      10.244.0.0/24
PodCIDRs:                     10.244.0.0/24
Non-terminated Pods:          (7 in total)
  Namespace                   Name                                      CPU Requests  CPU Limits  Memory Requests  Memory Limits  AGE
  ---------                   ----                                      ------------  ----------  ---------------  -------------  ---
  kube-system                 coredns-558bd4d5db-6g6gr                  100m (2%)     200m (5%)   70Mi (0%)        170Mi (1%)     18d
  kube-system                 coredns-558bd4d5db-pxgrt                  100m (2%)     200m (5%)   70Mi (0%)        170Mi (1%)     18d
  kube-system                 etcd-app-node                             100m (2%)     0 (0%)      100Mi (0%)       0 (0%)         18d
  kube-system                 kube-apiserver-app-node                   250m (6%)     0 (0%)      512Mi (3%)       0 (0%)         18d
  kube-system  

Conclusion

Listing all Pods and Nodes in a Kubernetes cluster is a fundamental skill for managing and monitoring your applications. By using kubectl, you can efficiently get an overview of your resources, filter them based on labels, and retrieve detailed information for specific resources. These commands are invaluable for debugging, monitoring, and ensuring the health of your Kubernetes environment.