CoreOS is used for the nodes. Every node has sda10 mounted to /var/lib/rook and sdb empty used as a whole. The nodes have been labelled according to the placements.

rook-cluster.yaml

apiVersion: rook.io/v1alpha1
kind: Cluster
metadata:
  name: rook
  namespace: rook
spec:
  versionTag: master
  dataDirHostPath: /var/lib/rook-config
  # toggle to use hostNetwork
  hostNetwork: true
  # set the amount of mons to be started
  monCount: 3
# To control where various services will be scheduled by kubernetes, use the placement configuration sections below.
# The example under 'all' would have all services scheduled on kubernetes nodes labeled with 'role=storage' and
# tolerate taints with a key of 'storage-node'.
  placement:
    all:
#      nodeAffinity:
#      tolerations:
    api:
      nodeAffinity:
        requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
          - matchExpressions:
            - key: storage.example.com/api
              operator: In
              values:
              - ""
#      tolerations:
    mon:
      podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values:
                    - rook-ceph-mon
              topologyKey: "kubernetes.io/hostname"
      nodeAffinity:
        requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
          - matchExpressions:
            - key: storage.example.com/mon
              operator: In
              values:
              - ""
#      tolerations:
    osd:
      nodeAffinity:
        requiredDuringSchedulingIgnoredDuringExecution:
          nodeSelectorTerms:
          - matchExpressions:
            - key: storage.example.com/osd
              operator: In
              values:
              - ""
#      tolerations:
    rgw:
      podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            - labelSelector:
                matchExpressions:
                  - key: "app"
                    operator: In
                    values:
                    - rook-ceph-rgw
              topologyKey: "kubernetes.io/hostname"
      nodeAffinity:
        nodeAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
            nodeSelectorTerms:
            - matchExpressions:
              - key: storage.example.com/rgw
                operator: In
                values:
                - ""
#      tolerations:
  storage:
    useAllNodes: false
    useAllDevices: false
    deviceFilter: ^sd(b)
    metadataDevice:
    location:
    storeConfig:
      storeType: bluestore
# Individual nodes and their config can be specified as well, but 'useAllNodes' above must be set to false. Then, only the named
# nodes below will be used as storage resources. Each node's 'name' field should match their 'kubernetes.io/hostname' label.
    nodes:
    - name: "kube-node-01.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-02.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-03.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-04.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-05.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-06.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-07.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"
    - name: "kube-node-08.example.com"
      directories:
      - path: "/var/lib/rook"
      devices:
      - name: "sdb"