六、K8S 使用Ceph存储
一、PV、PVC概述
管理存储是管理计算的一个明显问题。PersistentVolume子系统为用户和管理员提供了一个API,用于抽象如何根据消费方式提供存储的详细信息。于是引入了两个新的API资源:PersistentVolume和PersistentVolumeClaim >PersistentVolume(PV)是集群中已由管理员配置的一段网络存储。 集群中的资源就像一个节点是一个集群资源。 PV是诸如卷之类的卷插件,但是具有独立于使用PV的任何单个pod的生命周期。 该API对象包含存储的实现细节,即NFS,iSCSI或云提供商特定的存储系统。
PersistentVolumeClaim(PVC)是用户存储的请求。 它类似于pod。Pod消耗节点资源,PVC消耗存储资源。 pod可以请求特定级别的资源(CPU和内存)。 权限要求可以请求特定的大小和访问模式。
虽然PersistentVolumeClaims允许用户使用抽象存储资源,但是常见的是,用户需要具有不同属性(如性能)的PersistentVolumes,用于不同的问题。 管理员需要能够提供多种不同于PersistentVolumes,而不仅仅是大小和访问模式,而不会使用户了解这些卷的实现细节。 对于这些需求,存在StorageClass资源。
StorageClass为集群提供了一种描述他们提供的存储的“类”的方法。 不同的类可能映射到服务质量级别,或备份策略,或者由群集管理员确定的任意策略。 Kubernetes本身对于什么类别代表是不言而喻的。 这个概念有时在其他存储系统中称为“配置文件”
二、POD动态供给
动态供给主要是能够自动帮你创建pv,需要多大的空间就创建多大的pv。k8s帮助创建pv,创建pvc就直接api调用存储类来寻找pv。
如果是存储静态供给的话,会需要我们手动去创建pv,如果没有足够的资源,找不到合适的pv,那么pod就会处于pending等待的状态。而动态供给主要的一个实现就是StorageClass存储对象,其实它就是声明你使用哪个存储,然后帮你去连接,再帮你去自动创建pv。
三、POD使用RBD做为持久数据卷
3.1、安装与配置
RBD支持ReadWriteOnce,ReadOnlyMany两种模式
3.1.1、配置rbd-provisioner
# 如果使用kubeadm部署的集群需要这些额外的步骤 # 由于使用动态存储时 controller-manager 需要使用 rbd 命令创建 image # 所以 controller-manager 需要使用 rbd 命令 # 由于官方controller-manager镜像里没有rbd命令 # 如果没使用如下方式会报错无法成功创建pvc # 相关 issue https://github.com/kubernetes/kubernetes/issues/38923
cat >external-storage-rbd-provisioner.yaml<<EOF
apiVersion: v1
kind: ServiceAccount
metadata:
name: rbd-provisioner
namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: rbd-provisioner
rules:
- apiGroups: [""]
resources: ["persistentvolumes"]
verbs: ["get", "list", "watch", "create", "delete"]
- apiGroups: [""]
resources: ["persistentvolumeclaims"]
verbs: ["get", "list", "watch", "update"]
- apiGroups: ["storage.k8s.io"]
resources: ["storageclasses"]
verbs: ["get", "list", "watch"]
- apiGroups: [""]
resources: ["events"]
verbs: ["create", "update", "patch"]
- apiGroups: [""]
resources: ["endpoints"]
verbs: ["get", "list", "watch", "create", "update", "patch"]
- apiGroups: [""]
resources: ["services"]
resourceNames: ["kube-dns"]
verbs: ["list", "get"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: rbd-provisioner
subjects:
- kind: ServiceAccount
name: rbd-provisioner
namespace: kube-system
roleRef:
kind: ClusterRole
name: rbd-provisioner
apiGroup: rbac.authorization.k8s.io
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: rbd-provisioner
namespace: kube-system
rules:
- apiGroups: [""]
resources: ["secrets"]
verbs: ["get", "list", "watch", "create", "update", "patch"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: rbd-provisioner
namespace: kube-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: rbd-provisioner
subjects:
- kind: ServiceAccount
name: rbd-provisioner
namespace: kube-system
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: rbd-provisioner
namespace: kube-system
spec:
selector:
matchLabels:
app: rbd-provisioner
replicas: 1
strategy:
type: Recreate
template:
metadata:
labels:
app: rbd-provisioner
spec:
containers:
- name: rbd-provisioner
image: "quay.io/external_storage/rbd-provisioner:v2.0.0-k8s1.11"
env:
- name: PROVISIONER_NAME
value: ceph.com/rbd
serviceAccount: rbd-provisioner
EOF
# kubectl apply -f external-storage-rbd-provisioner.yaml
# 查看状态 等待running之后 再进行后续的操作
# kubectl get pod -n kube-system
1、创建pod时,kubelet需要使用rbd命令去检测和挂载pv对应的ceph image,所以要在所有的worker节点安装ceph客户端ceph-common。
将ceph的ceph.client.admin.keyring和ceph.conf文件拷贝到master的/etc/ceph目录下
yum -y install ceph-common
如果K8S中是没有ceph客户端和配置文件,需要从ceph集群中copy下:
scp /etc/ceph/ceph.c* root@192.168.171.11:/etc/ceph/
scp /etc/ceph/ceph.c* root@192.168.171.12:/etc/ceph/
scp /etc/ceph/ceph.c* root@192.168.171.13:/etc/ceph/
这样就可以在K8S集群中查看集群的状态了!
2、创建 osd pool 在ceph的mon或者admin节点
ceph osd pool create kube 128 128
ceph osd pool ls
3、创建k8s访问ceph的用户 在ceph的mon或者admin节点
ceph auth get-or-create client.kube mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=kube' -o ceph.client.kube.keyring
4、查看key 在ceph的mon或者admin节点
ceph auth get-key client.admin
ceph auth get-key client.kube
5、# 创建 admin secret # CEPH_ADMIN_SECRET 替换为 client.admin 获取到的key
kubectl create secret generic ceph-secret --type="kubernetes.io/rbd" \
--from-literal=key=AQCeEwpeo+I8HRAAnBphr8lyGc6+JBT7jU7rgA== \
--namespace=kube-system
6、# 在 default 命名空间创建pvc用于访问ceph的 secret # CEPH_KUBE_SECRET 替换为 client.kube 获取到的key
kubectl create secret generic ceph-user-secret --type="kubernetes.io/rbd" \
--from-literal=key=AQC3OhNeYrGQLRAA8Xd/e1NUto/fXnGEk6hVMg== \
--namespace=default
# 查看 secret
kubectl get secret ceph-user-secret -o yaml
kubectl get secret ceph-secret -n kube-system -o yaml
3.1.3、配置StorageClass
cat >storageclass-ceph-rdb.yaml<<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: dynamic-ceph-rdb
provisioner: ceph.com/rbd
parameters:
monitors: 192.168.171.135:6789,192.168.171.136:6789,192.168.171.137:6789
adminId: admin
adminSecretName: ceph-secret
adminSecretNamespace: kube-system
pool: kube
userId: kube
userSecretName: ceph-user-secret
fsType: ext4
imageFormat: "2"
imageFeatures: "layering"
EOF
kubectl apply -f storageclass-ceph-rdb.yaml
kubectl get sc
cat >ceph-rdb-pvc-test.yaml<<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: ceph-rdb-claim
spec:
accessModes:
- ReadWriteOnce
storageClassName: dynamic-ceph-rdb
resources:
requests:
storage: 2Gi
EOF
kubectl apply -f ceph-rdb-pvc-test.yaml
[root@k8s-master1 ~]# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
ceph-rdb-claim Bound pvc-e5f13194-67db-4d98-b69c-5a4272c2498d 2Gi RWO dynamic-ceph-rdb 7m10s
[root@k8s-master1 ~]# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-e5f13194-67db-4d98-b69c-5a4272c2498d 2Gi RWO Delete Bound default/ceph-rdb-claim dynamic-ceph-rdb 48s
cat >nginx-pod.yaml<<EOF
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod1
labels:
name: nginx-pod1
spec:
containers:
- name: nginx-pod1
image: nginx:alpine
ports:
- name: web
containerPort: 80
volumeMounts:
- name: ceph-rdb
mountPath: /usr/share/nginx/html
volumes:
- name: ceph-rdb
persistentVolumeClaim:
claimName: ceph-rdb-claim
EOF
kubectl apply -f nginx-pod.yaml
kubectl get pods -o wide
kubectl exec -ti nginx-pod1 -- /bin/sh -c 'echo Hello World from Ceph RBD!!! > /usr/share/nginx/html/index.html' # 访问测试
POD_ID=$(kubectl get pods -o wide | grep nginx-pod1 | awk '{print $6}')
curl http://$POD_ID #测试
kubectl delete -f nginx-pod.yaml
kubectl delete -f ceph-rdb-pvc-test.yaml
五、POD使用CephFS做为持久数据卷
CephFS方式支持k8s的pv的3种访问模式ReadWriteOnce,ReadOnlyMany ,ReadWriteMany
5.1、Ceph端创建CephFS pool
1、如下操作在ceph的mon或者admin节点 CephFS需要使用两个Pool来分别存储数据和元数据
ceph osd pool create fs_data 128
ceph osd pool create fs_metadata 128
ceph osd lspools
ceph fs new cephfs fs_metadata fs_data
ceph fs ls
5.2、部署 cephfs-provisioner
1、使用社区提供的cephfs-provisioner
cat >external-storage-cephfs-provisioner.yaml<<EOF
apiVersion: v1
kind: Namespace
metadata:
name: cephfs
labels:
name: cephfs
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: cephfs-provisioner
namespace: cephfs
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: cephfs-provisioner
namespace: cephfs
rules:
- apiGroups: [""]
resources: ["secrets"]
verbs: ["create", "get", "delete"]
- apiGroups: [""]
resources: ["endpoints"]
verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: cephfs-provisioner
namespace: cephfs
rules:
- apiGroups: [""]
resources: ["persistentvolumes"]
verbs: ["get", "list", "watch", "create", "delete"]
- apiGroups: [""]
resources: ["persistentvolumeclaims"]
verbs: ["get", "list", "watch", "update"]
- apiGroups: ["storage.k8s.io"]
resources: ["storageclasses"]
verbs: ["get", "list", "watch"]
- apiGroups: [""]
resources: ["events"]
verbs: ["create", "update", "patch"]
- apiGroups: [""]
resources: ["services"]
resourceNames: ["kube-dns","coredns"]
verbs: ["list", "get"]
- apiGroups: [""]
resources: ["secrets"]
verbs: ["get", "create", "delete"]
- apiGroups: ["policy"]
resourceNames: ["cephfs-provisioner"]
resources: ["podsecuritypolicies"]
verbs: ["use"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: cephfs-provisioner
namespace: cephfs
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: cephfs-provisioner
subjects:
- kind: ServiceAccount
name: cephfs-provisioner
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: cephfs-provisioner
subjects:
- kind: ServiceAccount
name: cephfs-provisioner
namespace: cephfs
roleRef:
kind: ClusterRole
name: cephfs-provisioner
apiGroup: rbac.authorization.k8s.io
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: cephfs-provisioner
namespace: cephfs
spec:
selector:
matchLabels:
app: cephfs-provisioner
replicas: 1
strategy:
type: Recreate
template:
metadata:
labels:
app: cephfs-provisioner
spec:
containers:
- name: cephfs-provisioner
image: "quay.io/external_storage/cephfs-provisioner:latest"
env:
- name: PROVISIONER_NAME
value: ceph.com/cephfs
command:
- "/usr/local/bin/cephfs-provisioner"
args:
- "-id=cephfs-provisioner-1"
- "-disable-ceph-namespace-isolation=true"
serviceAccount: cephfs-provisioner
EOF
kubectl apply -f external-storage-cephfs-provisioner.yaml
kubectl get pod -n cephfs
5.3、配置 storageclass
1、查看key 在ceph的mon或者admin节点
ceph auth get-key client.admin
kubectl create secret generic ceph-secret --type="kubernetes.io/rbd" \
--from-literal=key=AQCeEwpeo+I8HRAAnBphr8lyGc6+JBT7jU7rgA== \
--namespace=kube-system
kubectl get secret ceph-secret -n kube-system -o yaml
cat >storageclass-cephfs.yaml<<EOF
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
name: dynamic-cephfs
provisioner: ceph.com/cephfs
parameters:
monitors: 192.168.171.135:6789,192.168.171.136:6789,192.168.171.137:6789
adminId: admin
adminSecretName: ceph-secret
adminSecretNamespace: "kube-system"
claimRoot: /volumes/kubernetes
EOF
kubectl apply -f storageclass-cephfs.yaml
kubectl get sc
cat >cephfs-pvc-test.yaml<<EOF
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: cephfs-claim
spec:
accessModes:
- ReadWriteOnce
storageClassName: dynamic-cephfs
resources:
requests:
storage: 2Gi
EOF
kubectl apply -f cephfs-pvc-test.yaml
[root@k8s-master1 ceph-all]# kubectl get pvc
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
cephfs-claim Bound pvc-50ebdaab-c6ad-47ad-86cb-149327481a67 2Gi RWO dynamic-cephfs 4s
[root@k8s-master1 ceph-all]# kubectl get pv
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-50ebdaab-c6ad-47ad-86cb-149327481a67 2Gi RWO Delete Bound default/cephfs-claim dynamic-cephfs 6s
cat >nginx-pod.yaml<<EOF
apiVersion: v1
kind: Pod
metadata:
name: nginx-pod2
labels:
name: nginx-pod2
spec:
containers:
- name: nginx-pod2
image: nginx:alpine
ports:
- name: web
containerPort: 80
volumeMounts:
- name: cephfs
mountPath: /usr/share/nginx/html
volumes:
- name: cephfs
persistentVolumeClaim:
claimName: cephfs-claim
EOF
kubectl apply -f nginx-pod.yaml
kubectl get pods -o wide
kubectl exec -ti nginx-pod2 -- /bin/sh -c 'echo Hello World from CephFS!!! > /usr/share/nginx/html/index.html' # 访问测试
POD_ID=$(kubectl get pods -o wide | grep nginx-pod2 | awk '{print $6}')
curl http://$POD_ID
kubectl delete -f nginx-pod.yaml
kubectl delete -f cephfs-pvc-test.yaml
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