Creating a pod
kubectl run day5 --image nginx
Getting info about pod:
kubectl get pod day5 -oyaml
Whatever mentioned in the spec section that’s what the pod is going to do.
ImagePullPolicy: Official docs
apiVersion: v1 # API version for the Pod definition
kind: Pod # Defines the object type as a Pod
metadata: # Metadata about the pod
annotations: # Custom metadata annotations
cni.projectcalico.org/containerID: # Container ID for network plugin (Calico)
cni.projectcalico.org/podIP: # Pod's IP address
cni.projectcalico.org/podIPs: # List of pod IPs (single IP in this case)
creationTimestamp: "2024-10-20T13:14:46Z" # Time when the pod was created
labels: # Key-value pairs for identifying the pod
run: day5 # A label named 'run' with value 'day5'
name: day5 # Name of the pod
namespace: default # Namespace where the pod is running
resourceVersion: "2363" # Version of the pod resource for updates
uid: e1144b8f-1595-47a0-ab6d-676f2c93ab0c # Unique ID for the pod
spec: # Pod specification
containers: # List of containers within the pod
- image: nginx # Image to be used (nginx)
imagePullPolicy: Always # Always pull the latest image
name: day5 # Container name
resources: {} # No resource limits specified
terminationMessagePath: /dev/termination-log # Path for termination messages
terminationMessagePolicy: File # Use a file for termination messages
volumeMounts: # List of volumes mounted in the container
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount # Mount path for the service account token
name: kube-api-access-tn9nc # Volume name
readOnly: true # The volume is read-only
dnsPolicy: ClusterFirst # Use cluster's DNS for name resolution
enableServiceLinks: true # Allows service environment variables
nodeName: node01 # Node where the pod is running
preemptionPolicy: PreemptLowerPriority # Preempt lower-priority pods if needed
priority: 0 # Pod's priority (0 = lowest)
restartPolicy: Always # Always restart the pod on failure
schedulerName: default-scheduler # Scheduler to use (default)
securityContext: {} # Security settings (empty in this case)
serviceAccount: default # Service account name
serviceAccountName: default # Same as service account
terminationGracePeriodSeconds: 30 # Grace period before forcefully killing the pod
tolerations: # Conditions under which the pod is tolerated
- effect: NoExecute # Effect if the condition is met
key: node.kubernetes.io/not-ready # Tolerate 'not-ready' condition
operator: Exists # Tolerate if the key exists
tolerationSeconds: 300 # For 300 seconds
- effect: NoExecute # Same effect for 'unreachable' condition
key: node.kubernetes.io/unreachable # Tolerate 'unreachable' condition
operator: Exists # Tolerate if the key exists
tolerationSeconds: 300 # For 300 seconds
volumes: # Volumes defined for the pod
- name: kube-api-access-tn9nc # Volume name
projected: # Projected volume with multiple sources
defaultMode: 420 # File permissions for the volume
sources: # Sources for the volume
- serviceAccountToken: # Service account token for accessing API
expirationSeconds: 3607 # Token expiration time in seconds
path: token # Path for the token
- configMap: # Use ConfigMap for the CA certificate
items: # Specific items to mount
- key: ca.crt # CA certificate key
path: ca.crt # Path where it will be mounted
name: kube-root-ca.crt # Name of the ConfigMap
- downwardAPI: # Access downward API for pod metadata
items: # Items from the downward API
- fieldRef: # Reference to a field
apiVersion: v1 # API version of the field
fieldPath: metadata.namespace # Path to the namespace metadata
path: namespace # Mount path for the namespace info
status: # Current status of the pod
conditions: # List of pod conditions
- lastProbeTime: null # Last time condition was probed (null)
lastTransitionTime: "2024-10-20T13:14:53Z" # Last time condition transitioned
status: "True" # Condition is true
type: PodReadyToStartContainers # Condition type: Ready to start containers
- lastProbeTime: null # Same as above
lastTransitionTime: "2024-10-20T13:14:46Z" # Transition time for initialization
status: "True" # Initialization is complete
type: Initialized # Condition type: Initialized
- lastProbeTime: null # Same as above
lastTransitionTime: "2024-10-20T13:14:53Z" # Transition time for readiness
status: "True" # Pod is ready
type: Ready # Condition type: Ready
- lastProbeTime: null # Same as above
lastTransitionTime: "2024-10-20T13:14:53Z" # Time when containers became ready
status: "True" # Containers are ready
type: ContainersReady # Condition type: ContainersReady
- lastProbeTime: null # Same as above
lastTransitionTime: "2024-10-20T13:14:46Z" # Scheduled time for the pod
status: "True" # Pod is scheduled
type: PodScheduled # Condition type: PodScheduled
containerStatuses: # Status of the containers in the pod
- containerID: containerd://e5f98717eff0ad0038a4c5d9bfcedf206b3ef45b5bba9639183203ad04e9c438 # Container ID
image: docker.io/library/nginx:latest # Image used by the container
imageID: docker.io/library/nginx@sha256:28402db69fec7c17e179ea87882667f1e054391138f77ffaf0c3eb388efc3ffb # Image hash
lastState: {} # Last known state (empty in this case)
name: day5 # Container name
ready: true # Container is ready
restartCount: 0 # Number of restarts (none in this case)
started: true # Container has started
state: # Current state of the container
running: # Container is running
startedAt: "2024-10-20T13:14:53Z" # Time when the container started
volumeMounts: # Volume mounts for the container
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount # Service account mount
name: kube-api-access-tn9nc # Volume name
readOnly: true # Read-only access
recursiveReadOnly: Disabled # Recursive read-only is disabled
hostIP: 172.30.2.2 # IP address of the host node
hostIPs: # List of IPs for the host node
- ip: 172.30.2.2 # Host IP
phase: Running # Current phase of the pod (Running)
podIP: 192.168.1.4 # Pod's IP address
podIPs: # List of pod IPs
- ip: 192.168.1.4 # Pod's IP
qosClass: BestEffort # QoS class (BestEffort)
startTime: "2024-10-20T13:14:46Z" # Time when the pod started
Labels are key-value pair, if you don’t add labels kubernetes by default will add it.
Question: What if you don’t add the label then what will be the key-value of that lable?
Ans: The key will be run and value will be the name of the pod like in thiese way:
run: <pod-name>