K8S实现数据持久化存储

创建ConfigMap的方式key/value：命令行、yaml文件、指定文件创建、通过指定文件创建、作为卷挂载到pod
1、通过命令行参数创建
kubectl create configmap test1 --from-literal=hostname=10.244.255.254 --from-literal=port=80
kubectl get configmap
kubectl get configmap test1 -o yaml
生成测试的POD
vim nginx-deploy-cmd.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-cmd-test
labels:
app: nginx-cmd-test
spec:
replicas: 1
selector:
matchLabels:
app: nginx-cmd-test
template:
metadata:
labels:
app: nginx-cmd-test
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
env:
- name: nginx_port
valueFrom:
configMapKeyRef:
name: test1
key: port
- name: nginx_hostname
valueFrom:
configMapKeyRef:
name: test1
key: hostname

kubectl create -f nginx-deploy-cmd.yaml

2、编写yaml文件创建
vim configmap-test2.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: test2
data:
mysql_host: “10.244.255.253”
mysql_port: “3306”
mysql_user: “root”

kubectl create -f configmap-test2.yaml
kubectl get configmap
kubectl get configmap test2 -o yaml
3、通过指定文件创建
vim /etc/mongodb.conf
bind_ip=0.0.0.0
dbpath=/data/mongodb/db
logpath=/data/mongodb/log/mongodb.log
port=27017
logappend=true
fork=true
noauth=true

kubectl create configmap test3 --from-file=/etc/mongodb.conf
kubectl get configmap
kubectl get configmap test3 -o yaml

可通过如下命令修改key的值
kubectl create configmap --from-file==

4、通过指定目录创建
mkdir configfile
cd configfile
vim a.conf
name = zhangsan
age = 18
cellphone = 18100001111

vim b.conf
name = lisi
age = 25
cellphone = 18922221111

kubectl create configmap test4 --from-file=configfile
kubectl get configmap
kubectl get configmap test4 -o yaml

二、创建好configMap之后，使用configmap
1、通过环境变量传递
vim appvar.yaml //定义 ConfigMap 文件
apiVersion: v1
kind: ConfigMap
metadata:
name: appvar
data:
loglevel: warning
logdir: /var/log/nginx

vim app-test.yaml //定义 Pod 文件
apiVersion: v1
kind: Pod
metadata:
name: app-test
spec:
containers:

• name: app-test
  image: nginx:latest
  env:
  • name: APPLOG
    valueFrom:
    configMapKeyRef:
    name: appvar
    key: loglevel
  • name: APPDIR
    valueFrom:
    configMapKeyRef:
    name: appvar
    key: logdir

kubectl create -f appvar.yaml
kubectl create -f app-test.yaml
kubectl get pods
kubectl exec -it app-test – bash
echo $APPLOG
echo $APPDIR

新字段envFrom
vim app-test-1.yaml
apiVersion: v1
kind: Pod
metadata:
name: app-test-1
spec:
containers:

• name: app-test-1
  image: nginx:latest
  envFrom:
  • configMapRef:
    name: appvar

kubectl create -f app-test-1.yaml
kubectl get pods
kubectl exec -it app-test-1 – bash
echo $loglevel
echo $logdir

2、作为卷挂载到Pod
vim app-config-files.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: config-conf-files
data:
aconf:
“name = zhangsan\n
age = 18\n
cellphone = 18100001111\n”
bconf:
“name = lisi\n
age = 25\n
cellphone = 18922221111\n”

vim app-config-pod.yaml
apiVersion: v1
kind: Pod
metadata:
name: app-config-pod
spec:
containers:

• name: app-config-pod
  image: nginx:latest
  volumeMounts:
  • name: abconf //引用卷的名称
    mountPath: /data //挂载到 Pod 上的目录
    volumes:
• name: abconf //定义卷的名称
  configMap:
  name: config-conf-files //引用 ConfigMap
  items:
  • key: aconf
    path: a.conf //将 a.conf 文件名进行挂载
  • key: bconf
    path: b.conf //将 b.conf 文件名进行挂载

kubectl create -f app-config-files.yaml
kubectl create -f app-config-pod.yaml
kubectl exec -it app-config-pod – bash
cd /data
cat a.conf
cat b.conf

更新
vim appvar01.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: app-test
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:

• name: app-test
  image: nginx:latest
  env:
  • name: APPLOG
    valueFrom:
    configMapKeyRef:
    name: appvar
    key: loglevel
  • name: APPDIR
    valueFrom:
    configMapKeyRef:
    name: appvar
    key: logdir

vim appvar.yaml //定义 ConfigMap 文件
apiVersion: v1
kind: ConfigMap
metadata:
name: appvar
data:
loglevel: warning
logdir: /var/log/nginx

kubectl create -f appvar01.yaml

三、数据持久化
1、emptydir
最基础的卷类型就是emptyDir，顾名思义，一个emptyDir 卷是宿主机上的一个空目录，它是在Pod 分配到Node 时创建的，无需指定宿主机上对应的目录文件，并且是自动分配的。emptyDir 的生命周期跟Pod 相同，当Pod 从Node 节点上移除时，emptyDir卷中的数据也将被永久删除。

2、hostPath
hostPath 存储卷通常用于在Pod 上挂载宿主机上的文件或目录。在使用hostPath类型的存储卷时，也可以设置type 字段，类型有多种，包括：文件、目录、Socket 等。实际上hostPath 的功能就是docker 中的目录映射，只不过在K8S 中，Pod 会漂移，当Pod 漂移到其他node 节点上时，Pod 不会跨节点去读取原来的目录，此时它的数据就无法保证了。

3、其他类型卷
1）GcePersistentDisk：使用谷歌公有云提供的永久磁盘（Persistent Disk,简称PD）来存放卷中的数据。PD 上的内容会被永久保存，当Pod 被删除时，PD只是被卸载，需要先创建一个PD，才能使用gcePersistentDisk。
2）AwsElasticBlockStore：与GCE 类似，该类型的卷使用亚马逊公有云提供的EBS Volume 存储数据， 需要先创建EBS Volume ， 才能使用awsElasticBlockStore。
3）NFS 卷：使用NFS 网络文件系统提供的共享目录存储数据。
4）Iscsi：使用iSCSI 存储设备上的目录挂载到Pod 中。
5）Glusterfs：使用开源的GlusterFS 网络文件系统的目录挂载到Pod 中。

四、部署NFS：
1)基于NFS
K8S-master节点执行
yum -y install nfs-utils rpcbind
mkdir /nfsdata
vim /etc/exports
/nfsdata *(rw,sync,no_root_squash)
systemctl start rpcbind && systemctl enable rpcbind
systemctl start nfs-server && systemctl enable nfs-server
showmount -e

K8s-node1/k8s-node2节点执行
yum -y install nfs-utils rpcbind
showmount -e 192.168.180.210

创建PV（k8s-master/nfs服务器节点）
mkdir /nfsdata/pv
创建PV的yaml文件
vim pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv1
spec:
capacity:
storage: 1Gi
accessModes:

• ReadWriteOnce
  persistentVolumeReclaimPolicy: Recycle
  storageClassName: nfs
  nfs:
  path: /nfsdata/pv
  server: 192.168.180.210

kubectl create -f pv.yaml
kubectl get pv

创建PVC
vim pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: pvc1
spec:
accessModes:

• ReadWriteOnce
  resources:
  requests:
  storage: 200Mi
  storageClassName: nfs

kubectl create -f pvc.yaml
kubectl get pvc -o wide
kubectl get pv,pvc

vim pod.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: pod1
labels:
app: pod1
spec:
replicas: 1
selector:
matchLabels:
app: pod1
template:
metadata:
labels:
app: pod1
spec:
containers:

• name: pod1
  image: nginx:latest
  volumeMounts:
  • name: mydata
    mountPath: /usr/share/nginx/html
    volumes:

- name: mydata
  persistentVolumeClaim:
   claimName: pvc1

---

apiVersion: v1
kind: Service
metadata:
name: svc-pod1
labels:
app: svc-pod1
spec:
type: NodePort
ports:

• name: http
  protocol: TCP
  port: 80
  targetPort: 80
  nodePort: 30080
  selector:
  app: pod1

kubectl create -f pod.yaml
kubectl get pods,svc

cd /nfsdata/pv
ls
vim index.html

kubectl get pods
kubectl exec -it pod/pod1-97d8949d8-58n6p – bash
cat /usr/share/nginx/html/index.html

卷
2)emptyDir
vim emptydir.yaml
apiVersion: v1
kind: Pod
metadata:
name: test-pod-emptydir
spec:
containers:

• image: nginx
  name: emptydir-container
  volumeMounts:
  • mountPath: /usr/share/nginx/html
    name: htdocs-volume
    volumes:
• name: htdocs-volume
  emptyDir: {}

kubectl create -f emptydir.yaml
查看Pod分配在那个节点上
kubectl get pod -o wide
查看Pod上的容器ID
kubectl describe pod test-pod-emptydir
到对应的节点查看emptydir的挂载目录
docker inspect 6dc61858aa5f
省略部分内容…
“Mounts”: [
{
“Type”: “bind”,
“Source”: “/var/lib/kubelet/pods/fca55719-e8ab-4a45-b7c7-7a58947780d3/volumes/kubernetes.io~empty-dir/htdocs-volume”,
“Destination”: “/usr/share/nginx/html”,
“Mode”: “”,
“RW”: true,
“Propagation”: “rprivate”
},

3)hostPath
vim hostpath.yaml
apiVersion: v1
kind: Pod
metadata:
name: test-pod-hostpath
spec:
containers:

• image: nginx
  name: hostpath-container
  volumeMounts:
  • mountPath: /usr/share/nginx/html
    name: htdocs-volume
    volumes:
• name: htdocs-volume
  hostPath:
  path: /data

kubectl create -f hostpath.yaml
查看Pod分配到那个节点
kubectl get pods -o wide
查看当前的情况
curl 10.244.169.134
在相对应的节点执行
kubectl exec -it test-pod-hostpath – bash
echo "test page " > /usr/share/nginx/html/index.html
curl 10.244.169.134

基于PV 和 PVC 部署MySQL服务
1、创建PV及PVC
cd /nfsdata
mkdir mysql-pv

mkdir /mysql
cd /mysql
vim mysql-pv.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
name: mysql-pv
spec:
capacity:
storage: 1Gi
accessModes:

• ReadWriteOnce
  persistentVolumeReclaimPolicy: Retain
  storageClassName: nfs
  nfs:
  path: /nfsdata/mysql-pv
  server: 192.168.180.210

kubectl create -f mysql-pv.yaml
kubectl get pv

vim mysql-pvc.yaml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
name: mysql-pvc
spec:
accessModes:

• ReadWriteOnce
  resources:
  requests:
  storage: 1Gi
  storageClassName: nfs

kubectl create -f mysql-pvc.yaml
kubectl get pvc,pv

vim mysql.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: mysql
spec:
replicas: 1
selector:
matchLabels:
app: mysql
template:
metadata:
labels:
app: mysql
spec:
containers:

• name: mysql
  image: mysql:5.7
  env:
  • name: MYSQL_ROOT_PASSWORD
    value: 123456.com
    volumeMounts:
  • name: mysql-storage
    mountPath: /var/lib/mysql
    volumes:
• name: mysql-storage
  persistentVolumeClaim:
  claimName: mysql-pvc

---

apiVersion: v1
kind: Service
metadata:
name: mysql
spec:
type: NodePort
ports:

• name: http
  protocol: TCP
  port: 3306
  targetPort: 31306
  selector:
  app: mysql

kubectl create -f mysql.yaml
kubectl get pods,svc -o wide

kubectl exec -it pod/mysql-88558bbdf-hltxh – bash
mysql -uroot -p123456.com
show databases;
create database test;
use test;
create table my_id(id int(4));
insert my_id value(99);
select * from my_id;

模拟MYSQL故障
kubectl get pods -o wide
关闭对应节点，使POD在另一个节点服务器上重新生成