标签：-- table retain apply uber nginx ges 动态 dup
2个Kubernetes使用同一个Ceph存储达到Kubernetes间持久化数据迁移[TOC]
当前最新Kubernetes稳定版为1.14。现在为止，还没有不同Kubernetes间持久化存储迁移的方案。但根据Kubernetes pv/pvc绑定流程和原理，只要 "存储"-->"PV"-->"PVC" 的绑定关系相同，即可保证不同间Kubernetes可挂载相同的存储，并且里面是相同数据。
原来我的Kubernetes为阿里云ECS自己搭建的，现在想切换使用阿里云购买的Kubernetes。因Kubernetes中一些应用使用像1G、2G等小容量存储比较多，所以仍旧想保留原有的Ceph存储使用。
Kubernetes: v1.13.4
Ceph: 12.2.10 luminous (stable)
2个Kubernetes存储使用storageclass管理，并连接相同Ceph集群。可参考：Kubernetes使用Ceph动态卷部署应用
数据依旧保留在存储中，并未真正有迁移动作，迁移只是相对于不同Kubernetes来讲。
为了更好的看到效果，这里新建一个nginx的deploy，并使用ceph rbd做为持久化存储，然后写一些数据。
vim rbd-claim.yaml
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: rbd-pv-claim
spec:
accessModes:
- ReadWriteOnce
storageClassName: ceph-rbd
resources:
requests:
storage: 1Givim rbd-nginx-dy.yaml
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: nginx-rbd-dy
spec:
replicas: 1
template:
metadata:
labels:
name: nginx
spec:
containers:
- name: nginx
image: nginx
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
volumeMounts:
- name: ceph-cephfs-volume
mountPath: "/usr/share/nginx/html"
volumes:
- name: ceph-cephfs-volume
persistentVolumeClaim:
claimName: rbd-pv-claim# 创建pvc和deploy
kubectl create -f rbd-claim.yaml
kubectl create -f rbd-nginx-dy.yaml 查看结果，并写入数据至nginx持久化目录中：
pod/nginx-rbd-dy-7455884d49-rthzt 1/1 Running 0 4m31s
[root@node5 tmp]# kubectl get pvc,pod
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/rbd-pv-claim Bound pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee 1Gi RWO ceph-rbd 4m37s
NAME READY STATUS RESTARTS AGE
pod/nginx-rbd-dy-7455884d49-rthzt 1/1 Running 0 4m36s
[root@node5 tmp]# kubectl exec -it nginx-rbd-dy-7455884d49-rthzt /bin/bash
root@nginx-rbd-dy-7455884d49-rthzt:/# df -h
Filesystem Size Used Avail Use% Mounted on
overlay 40G 23G 15G 62% /
tmpfs 64M 0 64M 0% /dev
tmpfs 16G 0 16G 0% /sys/fs/cgroup
/dev/vda1 40G 23G 15G 62% /etc/hosts
shm 64M 0 64M 0% /dev/shm
/dev/rbd5 976M 2.6M 958M 1% /usr/share/nginx/html
tmpfs 16G 12K 16G 1% /run/secrets/kubernetes.io/serviceaccount
tmpfs 16G 0 16G 0% /proc/acpi
tmpfs 16G 0 16G 0% /proc/scsi
tmpfs 16G 0 16G 0% /sys/firmware
root@nginx-rbd-dy-7455884d49-rthzt:/# echo ygqygq2 > /usr/share/nginx/html/ygqygq2.html
root@nginx-rbd-dy-7455884d49-rthzt:/# exit
exit
[root@node5 tmp]# 将pv、pvc信息提取出来：
[root@node5 tmp]# kubectl get pvc rbd-pv-claim -oyaml --export > rbd-pv-claim-export.yaml
[root@node5 tmp]# kubectl get pv pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee -oyaml --export > pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee-export.yaml
[root@node5 tmp]# more rbd-pv-claim-export.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
annotations:
pv.kubernetes.io/bind-completed: "yes"
pv.kubernetes.io/bound-by-controller: "yes"
volume.beta.kubernetes.io/storage-provisioner: ceph.com/rbd
creationTimestamp: null
finalizers:
- kubernetes.io/pvc-protection
name: rbd-pv-claim
selfLink: /api/v1/namespaces/default/persistentvolumeclaims/rbd-pv-claim
spec:
accessModes:
- ReadWriteOnce
dataSource: null
resources:
requests:
storage: 1Gi
storageClassName: ceph-rbd
volumeMode: Filesystem
volumeName: pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee
status: {}
[root@node5 tmp]# more pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee-export.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
annotations:
pv.kubernetes.io/provisioned-by: ceph.com/rbd
rbdProvisionerIdentity: ceph.com/rbd
creationTimestamp: null
finalizers:
- kubernetes.io/pv-protection
name: pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee
selfLink: /api/v1/persistentvolumes/pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee
spec:
accessModes:
- ReadWriteOnce
capacity:
storage: 1Gi
claimRef:
apiVersion: v1
kind: PersistentVolumeClaim
name: rbd-pv-claim
namespace: default
resourceVersion: "51998402"
uid: d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee
persistentVolumeReclaimPolicy: Retain
rbd:
fsType: ext4
image: kubernetes-dynamic-pvc-dac8284a-6a1c-11e9-b533-1604a9a8a944
keyring: /etc/ceph/keyring
monitors:
- 172.18.43.220:6789
- 172.18.138.121:6789
- 172.18.228.201:6789
pool: kube
secretRef:
name: ceph-secret
namespace: kube-system
user: kube
storageClassName: ceph-rbd
volumeMode: Filesystem
status: {}
[root@node5 tmp]# 将上文中提取出来的pv和pvc传至新的Kubernetes中：
[root@node5 tmp]# rsync -avz pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee-export.yaml rbd-pv-claim-export.yaml rbd-nginx-dy.yaml 172.18.97.95:/tmp/
sending incremental file list
pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee-export.yaml
rbd-nginx-dy.yaml
rbd-pv-claim-export.yaml
sent 1,371 bytes received 73 bytes 2,888.00 bytes/sec
total size is 2,191 speedup is 1.52
[root@node5 tmp]# 在新的Kubernetes中导入pv、pvc：
[root@iZwz9g5ec0q4fc8iuqawr0Z tmp]# kubectl apply -f pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee-export.yaml -f rbd-pv-claim-export.yaml
persistentvolume/pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee created
persistentvolumeclaim/rbd-pv-claim created
[root@iZwz9g5ec0q4fc8iuqawr0Z tmp]# kubectl get pv pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee 1Gi RWO Retain Released default/rbd-pv-claim ceph-rbd 20s
[root@iZwz9g5ec0q4fc8iuqawr0Z tmp]# kubectl get pvc rbd-pv-claim
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
rbd-pv-claim Lost pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee 0 ceph-rbd 28s
[root@iZwz9g5ec0q4fc8iuqawr0Z tmp]# 可以看到，pvc状态显示为Lost，这是因为在新的Kubernetes中导入pv和pvc后，它们会自动重新生成自己的resourceVersion和uid，因此在新导入的pv中的spec.claimRef信息为旧的：
为了解决新导入的pv中的spec.claimRef信息旧的变成新的，我们将这段信息删除，由provisioner自动重新绑定它们的关系：
这里我们做成一个脚本处理：
vim unbound.sh
pv=$*
function unbound() {
kubectl patch pv -p ‘{"spec":{"claimRef":{"apiVersion":"","kind":"","name":"","namespace":"","resourceVersion":"","uid":""}}}‘ $pv
kubectl get pv $pv -oyaml> /tmp/.pv.yaml
sed ‘/claimRef/d‘ -i /tmp/.pv.yaml
#kubectl apply -f /tmp/.pv.yaml
kubectl replace -f /tmp/.pv.yaml
}
unboundsh unbound.sh pvc-d1cb2de6-6a1c-11e9-8124-eeeeeeeeeeee脚本执行后，过个10秒左右，查看结果：
在新的Kubernetes中使用之前传的rbd-nginx-dy.yaml验证下，在此之前，因为使用ceph rbd，需要先解除旧Kubernetes上的pod占用该rbd：
旧Kubernetes：
[root@node5 tmp]# kubectl delete -f rbd-nginx-dy.yaml
deployment.extensions "nginx-rbd-dy" deleted新Kubernetes：
上面实验中，使用的是RWO的pvc，大家试想下，如果使用RWX，多个Kubernetes使用，这种使用场景可能有更大的作用。
Kubernetes使用过程中，pv、pvc和存储，它们的信息和绑定关系至关重要，所以可按需求当作日常备份，有了这些备份，即使Kubernetes etcd数据损坏，也可达到恢复和迁移Kubernetes持久化数据目的。
2个Kubernetes使用同一个Ceph存储达到Kubernetes间持久化数据迁移
标签：-- table retain apply uber nginx ges 动态 dup
原文地址：https://blog.51cto.com/ygqygq2/2386424
