title: mapping values are not allowed in this context
body: <p>I'm a novice regarding YAML format and kubernetes.</p>
  
  <p>The following is a <em>dep_prom.yml</em> file.</p>
  
  <pre><code>---
  apiVersion: extensions/v1beta1
  kind: Deployment
  metadata:
    labels:
      name: prometheus-deployment
    name: prometheus
    #namespace: prometheus
  spec:
    replicas: 1
    template:
      metadata:
        labels:
          app: prometheus
      spec:
        containers:
        - image: prom/prometheus:master
          name: prometheus
          command:
          - "/bin/prometheus"
          args:
          - "-config.file=/etc/prometheus/prometheus.yml"
          - "-storage.local.path=/prometheus"
          - "-storage.local.retention=24h"
          ports:
          - containerPort: 9090
            protocol: TCP
          volumeMounts:
          - mountPath: "/prometheus"
            name: data
          - mountPath: "/etc/prometheus"
            name: config-volume
          resources:
            requests:
              cpu: 100m
              memory: 100Mi
            limits:
              cpu: 500m
              memory: 2500Mi
        volumes:
        - name: data
          hostPath:
            path: /data/prometheus
        - name: config-volume
          configMap:
            name: prometheus
        nodeSelector: westporch-kubeminion-1
          kubernetes.io/hostname: 10.0.24.52
  ---
  </code></pre>
  
  <p>However... When I executed <strong>kubectl create -f dep_prom.yml</strong> </p>
  
  <p><em>error: error converting YAML to JSON: yaml: line 47: mapping values are not allowed in this context</em></p>
  
  <p>Line 47 is <em>nodeSelector: westporch-kubeminion-1</em></p>
  
  <p>I think that YAML file format is normal. </p>
  
  <p>What is causing this error?</p>