Kubernetes PersistentVolumeClaim issues in AWS-using volumeClaimTemplates pending state - kubernetes

Question

We have success creating the pods, services and replication controllers according to our project requirements. Now we are planning to setup persistence storage in AWS using Kubernetes. I have created the YAML file to create an EBS volume in AWS, it's working fine as expected. I am able to claim volume and successfully mount to my pod (this is for single replica only).
I am able to successfully create the file.Volume also creating but my Pods is going to pending state, volume still shows available state in aws. I am not able to see any error logs over there.
Storage file:
kind: StorageClass
apiVersion: storage.k8s.io/v1beta1
metadata:
name: mongo-ssd
provisioner: kubernetes.io/aws-ebs
parameters:
type: gp2
Main file:
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
name: web2
spec:
selector:
matchLabels:
app: mongodb
serviceName: "mongodb"
replicas: 2
template:
metadata:
labels:
app: mongodb
annotations:
pod.alpha.kubernetes.io/initialized: "true"
spec:
containers:
- image: mongo
name: mongodb
ports:
- name: web2
containerPort: 27017
hostPort: 27017
volumeMounts:
- mountPath: "/opt/couchbase/var"
name: mypd1
volumeClaimTemplates:
- metadata:
name: mypd1
annotations:
volume.alpha.kubernetes.io/storage-class: mongo-ssd
spec:
accessModes: [ "ReadWriteOnce" ]
resources:
requests:
storage: 10Gi
Kubectl version:
Client Version: version.Info{Major:"1", Minor:"9", GitVersion:"v1.9.2", GitCommit:"5fa2db2bd46ac79e5e00a4e6ed24191080aa463b", GitTreeState:"clean", BuildDate:"2018-01-18T10:09:24Z", GoVersion:"go1.9.2", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"8", GitVersion:"v1.8.6", GitCommit:"6260bb08c46c31eea6cb538b34a9ceb3e406689c", GitTreeState:"clean", BuildDate:"2017-12-21T06:23:29Z", GoVersion:"go1.8.3", Compiler:"gc", Platform:"linux/amd64"}

Answer 1

I can see you have used hostPort in your container. In this case, If you do not have more than one node in your cluster, One Pod will remain pending. Because It will not fit any node.
containers:
- image: mongo
name: mongodb
ports:
- name: web2
containerPort: 27017
hostPort: 27017
I am getting this error when I describe my pending Pod
Type Reason Age From Message
---- ------ ---- ---- -------
Warning FailedScheduling 27s (x7 over 58s) default-scheduler No nodes are available that match all of the predicates: PodFitsHostPorts (1).
HostPort in your container will be bind with your node. Suppose, you are using HostPort 10733, but another pod is already using that port, now you pod can't use that. So it will be in pending state. And If you have replica 2, and both pod is deployed in same node, they can't be started either.
So, you need to use a port as HostPort, that you can surely say that no one else is using.