Where is kube-apiserver located

Question

Base question: When I try to use kube-apiserver on my master node, I get command not found error. How I can install/configure kube-apiserver? Any link to example will help.

$ kube-apiserver --enable-admission-plugins DefaultStorageClass
-bash: kube-apiserver: command not found

Details: I am new to Kubernetes and Docker and was trying to create StatefulSet with volumeClaimTemplates. My problem is that the automatic PVs are not created and I get this message in the PVC log: "persistentvolume-controller waiting for a volume to be created". I am not sure if I need to define DefaultStorageClass and so needed kube-apiserver to define it.

Name:          nfs
Namespace:     default
StorageClass:  example-nfs
Status:        Pending
Volume:
Labels:        <none>
Annotations:   volume.beta.kubernetes.io/storage-provisioner=example.com/nfs
Finalizers:    [kubernetes.io/pvc-protection]
Capacity:
Access Modes:
Events:
  Type    Reason                Age                  From                         Message
  ----    ------                ----                 ----                         -------
  Normal  ExternalProvisioning  3m (x2401 over 10h)  persistentvolume-controller  waiting for a volume to be created, either by external provisioner "example.com/nfs" or manually created by system administrator

Here is get pvc result:

$ kubectl get pvc
NAME      STATUS    VOLUME    CAPACITY   ACCESS MODES   STORAGECLASS   AGE
nfs       Pending                                       example-nfs    10h

And get storageclass:

$ kubectl describe storageclass example-nfs
Name:                  example-nfs
IsDefaultClass:        No
Annotations:           <none>
Provisioner:           example.com/nfs
Parameters:            <none>
AllowVolumeExpansion:  <unset>
MountOptions:          <none>
ReclaimPolicy:         Delete
VolumeBindingMode:     Immediate
Events:                <none>

How can I troubleshoot this issue (e.g. logs for why the storage was not created)?

Answer 1

You are asking two different questions here, one about kube-apiserver configuration, one about troubleshooting your StorageClass.

Here's an answer for your first question:

kube-apiserver is running as a Docker container on your master node. Therefore, the binary is within the container, not on your host system. It is started by the master's kubelet from a file located at /etc/kubernetes/manifests. kubelet is watching this directory and will start any Pod defined here as "static pods".

To configure kube-apiserver command line arguments you need to modify /etc/kubernetes/manifests/kube-apiserver.yaml on your master.

Answer 2

To make the storage class "example-nfs" default, you need to run the below command:

kubectl patch storageclass example-nfs -p '{"metadata": 
  {"annotations": {"storageclass.kubernetes.io/is-default-class": "true"}}}'