λ kubectl cluster-info
Kubernetes master is running at https://ucp.yyy.com:6443
KubeDNS is running at https://ucp.yyy.com:6443/api/v1/namespaces/kube-system/services/kube-dns/proxy

To further debug and diagnose cluster problems, use ‘kubectl cluster-info dump’.

C:\ovi\docker

Create a namespace called ‘ovi’

kubectl create namespace ovi

C:\ovi\docker
λ kubectl get namespaces | grep ovi
ovi       Active   117d
ovitest  Active    75d

C:\ovi\docker
λ kubectl create namespace ovi2
namespace “ovi2” created

C:\ovi\docker
λ kubectl delete namespace ovi2
namespace “ovi2” deleted

C:\ovi\docker
λ kubectl get namespaces ovi
NAME   STATUS    AGE
ovi         Active      118d

C:\ovi\docker
λ kubectl run nginx –image=dtr.yyy.com/dev.yyy.com/nginx:1.13.5-alpine –restart=Never -n ovitest
pod “nginx” created

 

Deploy first app

1.

C:\ovi\Kubernetes_labT
λ kubectl run –image=dtr.yyy.com/dev.yyy.com/nginx:1.13.5-alpine ovi-nginx -n ovi

2.

C:\ovi\Kubernetes_labT
λ kubectl expose deployment ovi-nginx –type=NodePort –port=80 -n ovi

deployment “ovi-nginx” created

3.

C:\ovi\Kubernetes_labT
λ kubectl describe service ovi-nginx -n ovi
Name: ovi-nginx
Namespace: ovi
Labels: run=ovi-nginx
Annotations: <none>
Selector: run=ovi-nginx
Type: NodePort
IP: 10.96.195.143
Port: <unset> 80/TCP
TargetPort: 80/TCP
NodePort: <unset> 33368/TCP
Endpoints: 192.168.158.31:80
Session Affinity: None
External Traffic Policy: Cluster
Events: <none>

4.

C:\ovi\Kubernetes_labT
λ kubectl get pods -n ovi
NAME                                          READY STATUS      RESTARTS   AGE
ovi-nginx-97db6b48b-zt6tk           1/1     Running           0           15m
run-ovinginx-7559884b7b-7nps6 1/1      Running           0            2d

5.

λ kubectl describe pods ovi-nginx-97db6b48b-zt6tk -n ovi

 

6. test from browser

http://nodeIP:33368

 

Other commands

 

C:\ovi\Kubernetes_labT
λ kubectl logs ovi-tomcat8-5cd599dd45-bzgk7 -n ovi

….

06-Feb-2019 20:20:03.407 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler [“http-nio-8080”]
06-Feb-2019 20:20:03.413 INFO [main] org.apache.coyote.AbstractProtocol.start Starting ProtocolHandler [“ajp-nio-8009”]
06-Feb-2019 20:20:03.414 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 618 ms

C:\ovi\docker
λ kubectl get pods –namespace=ovitest
NAME   READY   STATUS   RESTARTS     AGE
nginx      1/1      Running         0              9m

C:\ovi\docker
λ kubectl get pods –all-namespaces | grep ovitest
ovitest nginx 1/1 Running 0 3m

kubectl describe pods nginx –namespace=ovitest

C:\ovi\docker
λ kubectl describe pods/nginx -n ovitest

 

C:\ovi\docker
λ kubectl get pod -o wide –namespace=ovitest
NAME READY    STATUS    RESTARTS   AGE                 IP                NODE
nginx     1/1       Running         0            59m           192.168.80.2    ovi.com

C:\ovi\docker
λ kubectl get namespaces –show-labels

kubectl run nginx –image=nginx –restart=Never -n ovi

λ kubectl get po –all-namespaces -o wide

Check ingress-controller

C:\ovi\docker
λ kubectl get pod -n ingress-nginx
NAME                                                              READY                  STATUS             RESTARTS      AGE
default-http-backend-67f6f4bdc-n6fdt            0/1                 ContainerCreating       0                3d
nginx-ingress-controller-584dc49b67-qjbpw    0/1                           Init:0/1              0                3d

 

$ kubectl get pod -n kube-system

C:\ovi\Kubernetes_labT
λ kubectl get pods -n ovi
NAME                                           READY      STATUS                  RESTARTS      AGE
ovi-nginx-97db6b48b-zt6tk              1/1        Running                       0                1h
ovi-tomcat-56d8469df-rgd62           0/1        ImagePullBackOff       0                 31m
ovi-tomcat8-5cd599dd45-bzgk7      1/1        Running                      0                26m
run-ovinginx-7559884b7b-7nps6      1/1       Running                     0                 2d

 

C:\ovi\Kubernetes_labT
λ kubectl run nginx –image=nginx –restart=Never -n mynamespace –dry-run -o yaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: nginx
name: nginx
spec:
containers:
–  image: nginx
imagePullPolicy: IfNotPresent
name: nginx
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Never
status: {}

 

Edit ResourceQuota

C:\ovi\docker
λ kubectl describe quota -n ovi

Name: ovi-resourcequota
Namespace: ovi
Resource          Used      Hard
——– —- —- ————
limits.cpu          3500m     8
limits.memory    7Gi     16Gi
pods                   7          24
requests.cpu             3100m 8
requests.memory 6720Mi 16Gi

 

C:\ovi\docker
λ kubectl get resourcequota ovi-resourcequota –namespace=ovi –output=yaml

 

C:\ovi\docker
λ kubectl edit resourcequota ovi-resourcequota –namespace=ovi

 

you can log to container

kubectl exec ${POD_NAME} -c ${CONTAINER_NAME} — ${CMD} ${ARG1} ${ARG2} … ${ARGN}

 

C:\ovi\docker
λ kubectl describe nodes 2>&1 | grep -i Disk

 

Reasons k8S Deployments Faill 

1.  Wrong Container Image / Invalid Registry Permissions
2. Application Crashing after Launch
3. Missing ConfigMap or Secret
4. Liveness/Readiness Probe Failure
5. Exceeding CPU/Memory Limits
6. Resource Quotas
7. Insufficient Cluster Resources
8. PersistentVolume fails to mount
9. Validation Errors
10. Container Image Not Updating

 

View the containers in the pod:

docker ps

Get the process ID for the container:

docker inspect --format '{{ .State.Pid }}' [container_id]

Use nsenter to run a command in the process’s network namespace:

nsenter -t [container_pid] -n ip addr