#Creating the Deployment
kubectl create deployment myapp2 --image=docker.io/openshift/hello-openshift
deployment.apps/myapp2 created
#Verify the Deployment and Pods’ states
kubectl get po
NAME READY STATUS RESTARTS AGE
myapp2-757cc77ff9-lnzwc 1/1 Running 0 8s
#describe Pod content
kubectl describe po myapp2-757cc77ff9-lnzwc
Name: myapp2-757cc77ff9-lnzwc
Namespace: default
Priority: 0
Node: node-2.example.com/172.31.55.63
Start Time: Thu, 30 Jun 2022 22:52:42 +0000
Labels: app=myapp2
pod-template-hash=757cc77ff9
Annotations: <none>
Status: Running
IP: 10.36.0.5
IPs:
IP: 10.36.0.5
Controlled By: ReplicaSet/myapp2-757cc77ff9
Containers:
hello-openshift:
Container ID: docker://f39e3bfb9b6b4cdf127dfd8368ec76610078d64c79516e70848b884d2e6e4be7
Image: docker.io/openshift/hello-openshift
Image ID: docker-pullable://openshift/hello-openshift@sha256:aaea76ff622d2f8bcb32e538e7b3cd0ef6d291953f3e7c9f556c1ba5baf47e2e
Port: <none>
Host Port: <none>
State: Running
Started: Thu, 30 Jun 2022 22:52:44 +0000
Ready: True
Restart Count: 0
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-x5skk (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-x5skk:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: BestEffort
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 98s default-scheduler Successfully assigned default/myapp2-757cc77ff9-lnzwc to node-2.example.com
Normal Pulling 98s kubelet Pulling image "docker.io/openshift/hello-openshift"
Normal Pulled 97s kubelet Successfully pulled image "docker.io/openshift/hello-openshift" in 827.570703ms
Normal Created 97s kubelet Created container hello-openshift
Normal Started 97s kubelet Started container hello-openshift
#to get running Deployment
kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
myapp2 1/1 1 1 4m14s
#to describe content
kubectl describe deployment myapp2
Name: myapp2
Namespace: default
CreationTimestamp: Thu, 30 Jun 2022 22:52:42 +0000
Labels: app=myapp2
Annotations: deployment.kubernetes.io/revision: 1
Selector: app=myapp2
Replicas: 1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType: RollingUpdate
MinReadySeconds: 0
RollingUpdateStrategy: 25% max unavailable, 25% max surge
Pod Template:
Labels: app=myapp2
Containers:
hello-openshift:
Image: docker.io/openshift/hello-openshift
Port: <none>
Host Port: <none>
Environment: <none>
Mounts: <none>
Volumes: <none>
Conditions:
Type Status Reason
---- ------ ------
Available True MinimumReplicasAvailable
Progressing True NewReplicaSetAvailable
OldReplicaSets: <none>
NewReplicaSet: myapp2-757cc77ff9 (1/1 replicas created)
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal ScalingReplicaSet 10m deployment-controller Scaled up replica set myapp2-757cc77ff9 to 1
#create a yaml file
kubectl create deployment myhttpd --image=docker.io/httpd --dry-run=client -o yaml > mydep.yaml
cat mydep.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
creationTimestamp: null
labels:
app: myhttpd
name: myhttpd
spec:
replicas: 1
selector:
matchLabels:
app: myhttpd
strategy: {}
template:
metadata:
creationTimestamp: null
labels:
app: myhttpd
spec:
containers:
- image: docker.io/httpd
name: httpd
resources: {}
status: {}
#Create the Deployment
kubectl apply -f mydep.yaml
deployment.apps/myhttpd created
kubectl get deployment
NAME READY UP-TO-DATE AVAILABLE AGE
myhttpd 1/1 1 1 11s
#Expose the Deployment to create a service
kubectl expose deployment myhttpd --port=8080
service/myhttpd exposed
#Verify the created services
kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 7d9h
myhttpd ClusterIP 10.110.234.236 <none> 8080/TCP 9s
#Describe the service
kubectl describe svc myhttpd
Name: myhttpd
Namespace: default
Labels: app=myhttpd
Annotations: <none>
Selector: app=myhttpd
Type: ClusterIP
IP Family Policy: SingleStack
IP Families: IPv4
IP: 10.110.234.236
IPs: 10.110.234.236
Port: <unset> 8080/TCP
TargetPort: 8080/TCP
Endpoints: 10.36.0.5:8080
Session Affinity: None
Events: <none>
Creating the namespaces
#create specific namespaces
kubectl create namespace mynamespace
namespace/mynamespace created
#Verify the namespace
kubectl get namespace
NAME STATUS AGE
default Active 7d9h
kube-node-lease Active 7d9h
kube-public Active 7d9h
kube-system Active 7d9h
mynamespace Active 8s
Scaling and deleting the Deployment
#create a Deployment in a particular namespace
kubectl create deployment myhttpd --image=docker.io/httpd -n mynamespace
deployment.apps/myhttpd created
kubectl get deployment -n mynamespace
NAME READY UP-TO-DATE AVAILABLE AGE
myhttpd 1/1 1 1 2m39s
kubectl get pods -n mynamespace
NAME READY STATUS RESTARTS AGE
myhttpd-78f86b45d5-pd2ph 1/1 Running 0 3m5s
#Scale the Deployment
kubectl scale --replicas=3 deployment myhttpd -n mynamespace
deployment.apps/myhttpd scaled
kubectl get deployment -n mynamespace
NAME READY UP-TO-DATE AVAILABLE AGE
myhttpd 3/3 3 3 4m49s
#get the endpoints
kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 172.31.54.141:6443 7d10h
myhttpd 10.36.0.5:8080 39m
kubectl describe endpoints
Name: kubernetes
Namespace: default
Labels: endpointslice.kubernetes.io/skip-mirror=true
Annotations: <none>
Subsets:
Addresses: 172.31.54.141
NotReadyAddresses: <none>
Ports:
Name Port Protocol
---- ---- --------
https 6443 TCP
Events: <none>
Name: myhttpd
Namespace: default
Labels: app=myhttpd
Annotations: endpoints.kubernetes.io/last-change-trigger-time: 2022-07-03T01:32:13Z
Delete the created Pods, Deployment, service, and namespace
kubectl delete deployment myhttpd
deployment.apps "myhttpd" deleted
kubectl delete svc myhttpd
service "myhttpd" deleted
kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 7d10h
kubectl delete namespace mynamespace
namespace "mynamespace" deleted
#Verify the events
kubectl get events
LAST SEEN TYPE REASON OBJECT MESSAGE
57m Normal Starting node/main.example.com Starting kubelet.
57m Normal NodeHasSufficientMemory node/main.example.com Node main.example.com status is now: NodeHasSufficientMemory
57m Normal NodeHasNoDiskPressure node/main.example.com Node main.example.com status is now: NodeHasNoDiskPressure
57m Normal NodeHasSufficientPID node/main.example.com Node main.example.com status is now: NodeHasSufficientPID
57m Normal NodeAllocatableEnforced node/main.example.com Updated Node Allocatable limit across pods
<...>
#Verify the Nodes’ state
kubectl get nodes
NAME STATUS ROLES AGE VERSION
node.example.com Ready control-plane,main 7d10h v1.23.4
node-1.example.com Ready <none> 7d10h v1.23.4
node-2.example.com Ready <none> 7d10h v1.23.4
#describe Nodes’
kubectl describe node node-1.example.com
Name: node-1.example.com
Roles: <none>
Labels: beta.kubernetes.io/arch=amd64
beta.kubernetes.io/os=linux
kubernetes.io/arch=amd64
kubernetes.io/hostname=worker-node-1.example.com
kubernetes.io/os=linux
Annotations: kubeadm.alpha.kubernetes.io/cri-socket: /var/run/dockershim.sock
node.alpha.kubernetes.io/ttl: 0
volumes.kubernetes.io/controller-managed-attach-detach: true
<...>
