Manual Scheduling Kubernetes

A pod definition file nginx.yaml is given. Create a pod using the file. Only create the POD for now. We will inspect its status next.

master $ ls -ltr
total 12
drwxr-xr-x 2 root root 4096 May 21 12:41 Desktop
drwxr-xr-x 4 root root 4096 Jun  8 22:04 go
-rw-r--r-- 1 root root  103 Jul 14 00:42 nginx.yaml
master $ kubectl apply -f nginx.yaml
pod/nginx created
master $ kubectl get pods
NAME    READY   STATUS    RESTARTS   AGE
nginx   0/1     Pending   0          4s

What is the status of the created POD?

master $ kubectl get pods

NAME    READY   STATUS    RESTARTS   AGE

nginx   0/1     Pending   0          4s

Why is the POD in a pending state? Inspect the environment for various kubernetes control plane components.

master $ kubectl get pods --namespace kube-system

NAME                                      READY   STATUS    RESTARTS   AGE

coredns-66bff467f8-4fqx2                  1/1     Running   0          5m25s

coredns-66bff467f8-4p4lf                  1/1     Running   0          5m25s

etcd-master                               1/1     Running   0          5m40s

katacoda-cloud-provider-58f89f7d9-jrdtb   0/1     Pending   0          5m24s

kube-apiserver-master                     1/1     Running   0          5m40s

kube-controller-manager-master            1/1     Running   0          5m40s

kube-flannel-ds-amd64-ljdg5               1/1     Running   1          5m3s

kube-flannel-ds-amd64-w94gq               1/1     Running   0          5m25s

kube-keepalived-vip-whfmw                 1/1     Running   0          4m43s

kube-proxy-44hxg                          1/1     Running   0          5m3s

kube-proxy-w952d                          1/1     Running   0          5m25s

Answer:  no scheduler present

Manually schedule the pod on node01 Delete and re-create the POD if necessary

master $ kubectl get nodes

NAME     STATUS   ROLES    AGE     VERSION

master   Ready    master   10m     v1.18.0

node01   Ready    <none>   9m34s   v1.18.0

master $ vi nginx.yaml

Now edit the nginx.yaml to include node01 as the nodeName and save it

master $ kubectl get pods

NAME    READY   STATUS    RESTARTS   AGE

nginx   0/1     Pending   0          8m48s

master $ kubectl delete pods nginx

pod "nginx" deleted

master $ kubectl apply -f nginx.yaml

pod/nginx created

master $ kubectl get pods

NAME    READY   STATUS              RESTARTS   AGE

nginx   0/1     ContainerCreating   0          6s

master $ kubectl get pods

NAME    READY   STATUS    RESTARTS   AGE

nginx   1/1     Running   0          11s

Now schedule the same pod on the master node. Delete and recreate the POD if necessary

Repeat the same process as above this time changing the nodeName to master.