k8s中部署有状态应用等需要持久化数据的应用，必不可少得用存储，k8s支持很多中存储方案，我司目前使用的存储有glusterfs(分为容器化和裸机方式)、nfs供应用选用，本次就简单实战下glusterfs配合k8s做数据存储。
介绍
GlusterFS系统是一个可扩展的网络文件系统，相比其他分布式文件系统，GlusterFS具有高扩展性、高可用性、高性能、可横向扩展等特点，并且其没有元数据服务器的设计，让整个服务没有单点故障的隐患。
规划
192.168.209.130 master-01
192.168.209.131 master-02
192.168.209.132 master-03
以上三台作为主控并作为GlusterFS集群节点。
添加hosts
[root@master-01 gluster]# cat /etc/hosts
192.168.209.130 master-01
192.168.209.131 master-02
192.168.209.132 master-03
安装GlusterFS
GlusterFS默认配置文件在/etc/glusterfs/glusterd.vol
工作目录默认在/var/lib/glusterfsd
[root@master-01 ~]#yum install -y centos-release-gluster glusterfs glusterfs-server glusterfs-fuse
[root@master-01 ~]#systemctl start glusterd
[root@master-01 ~]# systemctl status glusterd
● glusterd.service - GlusterFS, a clustered file-system server
Loaded: loaded (/usr/lib/systemd/system/glusterd.service; disabled; vendor preset: disabled)
Active: active (running) since 日 2019-04-28 13:20:08 CST; 2min 57s ago
Docs: man:glusterd(8)
集群配置
[root@master-01 ~]# gluster peer probe master-01
peer probe: success. Probe on localhost not needed
[root@master-01 ~]# gluster peer probe master-02
peer probe: success.
[root@master-01 ~]# gluster peer probe master-03
peer probe: success.
创建卷并启动
[root@master-01 ~]# gluster volume create gv0 replica 3 master-01:/opt/data/gv0 master-02:/opt/data/gv0 master-03:/opt/data/gv0 force
volume create: gv0: success: please start the volume to access data
[root@master-01 ~]# gluster volume start gv0
volume start: gv0: success
默认不支持使用/分区作为存储路径，我这没有数据盘，所以使用force强制创建了。
/opt/data/gv0目录得先在三台机器上都创建。
查看节点和卷信息
[root@master-01 ~]# gluster peer status
Number of Peers: 2
Hostname: master-02
Uuid: 6f5a823c-4044-4dd9-95bc-129018b2eec0
State: Peer in Cluster (Connected)
Hostname: master-03
Uuid: dfeb6d81-c90b-4628-82f2-e379ed0ceded
State: Peer in Cluster (Connected)
[root@master-01 ~]# gluster volume info
Volume Name: gv0
Type: Replicate
Volume ID: 1891c9f8-8acb-48c2-94d9-29e2a625f9a0
Status: Started
Snapshot Count: 0
Number of Bricks: 1 x 3 = 3
Transport-type: tcp
Bricks:
Brick1: master-01:/opt/data/gv0
Brick2: master-02:/opt/data/gv0
Brick3: master-03:/opt/data/gv0
Options Reconfigured:
transport.address-family: inet
nfs.disable: on
performance.client-io-threads: off
查看端口监听
[root@master-01 ~]# netstat -tunlp|grep glusterd
tcp 0 0 0.0.0.0:24007 0.0.0.0:* LISTEN 19533/glusterd
测试挂载
想要正常的在kubernetes集群中使用或者挂载glusterfs，集群中的对应节点都需要安装 glusterfs-fuse
[root@harbor-01 harbor]# yum install -y centos-release-gluster glusterfs-fuse
[root@master-01 ~]# mount -t glusterfs master-01:/gv0 /mnt
[root@master-01 ~]# df -h
...
master-01:/gv0 38G 13G 25G 34% /mnt
常用命令
#删除卷
gluster volume stop gv0
gluster volume delete gv0
#将机器移出集群
gluster peer detach master-01
#只允许172.28.0.0的网络访问glusterfs
gluster volume set gv0 auth.allow 172.28.26.*
gluster volume set gv0 auth.allow 192.168.222.1,192.168.*.*
#加入新的机器并添加到卷里(由于副本数设置为2,至少要添加2（4、6、8..）台机器)
gluster peer probe master-02
gluster peer probe master-03
#新加卷
gluster volume add-brick gv0 repl 2 master-02:/data/gluster master-03:/data/gluster force
#删除卷
gluster volume remove-brick gv0 repl 2 master-02:/opt/data/gv0 master-03:/opt/data/gv0 start
gluster volume remove-brick gv0 repl 2 master-02:/opt/data/gv0 master-03:/opt/data/gv0 status
gluster volume remove-brick gv0 repl 2 master-02:/opt/data/gv0 master-03:/opt/data/gv0 commit
注意：扩展或收缩卷时，也要按照卷的类型，加入或减少的brick个数必须满足相应的要求。
#当对卷进行了扩展或收缩后，需要对卷的数据进行重新均衡。
gluster volume rebalance mamm-volume start|stop|status
###########################################################
迁移卷---主要完成数据在卷之间的在线迁移
#启动迁移过程
gluster volume replace-brick gv0 master-02:/opt/data/gv0 master-02:/opt/test start force
#查看迁移状态
gluster volume replace-brick gv0 master-02:/opt/data/gv0 master-02:/opt/test status
#迁移完成后提交完成
gluster volume replace-brick gv0 master-02:/opt/data/gv0 master-02:/opt/test commit
#机器出现故障,执行强制提交
gluster volume replace-brick gv0 master-02:/opt/data/gv0 master-02:/opt/test commit force
###########################################################
触发副本自愈
gluster volume heal mamm-volume #只修复有问题的文件
gluster volume heal mamm-volume full #修复所有文件
gluster volume heal mamm-volume info #查看自愈详情
#####################################################
data-self-heal, metadata-self-heal and entry-self-heal
启用或禁用文件内容、文件元数据和目录项的自我修复功能，默认情况下三个全部是“on”。
#将其中的一个设置为off的范例：
gluster volume set gv0 entry-self-heal off
到这一步GlusterFS就部署完成了，接下来就在k8s使用它。
创建Endpoints
# ep 编排
[root@master-01 gluster]# cat gluster-ep.yaml
apiVersion: v1
kind: Endpoints
metadata:
name: glusterfs-cluster
subsets:
- addresses:
- ip: 192.168.209.130
- ip: 192.168.209.131
- ip: 192.168.209.132
ports:
- port: 1990
protocol: TCP
---
kind: Service
apiVersion: v1
metadata:
name: glusterfs-cluster
spec:
ports:
- port: 1990
# 开始创建
[root@master-01 gluster]# kubectl apply -f gluster-ep.yaml
endpoints/glusterfs-cluster created
service/glusterfs-cluster created
# 查看状态结果
[root@master-01 gluster]# kubectl get ep,svc|grep glusterfs
endpoints/glusterfs-cluster 192.168.209.130:1990,192.168.209.131:1990,192.168.209.132:1990 2m4s
service/glusterfs-cluster ClusterIP 10.254.120.33 <none> 1990/TCP 2m4s
创建Pv/Pvc
# 编排
[root@master-01 gluster]# cat gluster-pvc.yaml
---
apiVersion: v1
kind: PersistentVolume # pv
metadata:
name: test-pv
namespace: default
labels:
alicloud-pvname: test-pv
spec: # 定义pv属性
capacity: # 容量
storage: 2Gi # 存储容量
accessModes: # 访问模式,支持ReadWriteOnce、ReadOnlyMany和ReadWriteMany
- ReadWriteMany
glusterfs:
endpoints: 'glusterfs-cluster'
path: 'gv0'
readOnly: false
persistentVolumeReclaimPolicy: Recycle
---
kind: PersistentVolumeClaim # pvc
apiVersion: v1
metadata:
name: test-pvc
namespace: default
spec:
accessModes:
- ReadWriteMany
resources:
requests:
storage: 2Gi
selector:
matchLabels:
alicloud-pvname: test-pv
# 开始创建
[root@master-01 gluster]# kubectl apply -f gluster-pvc.yaml
persistentvolume/dt-pv created
persistentvolumeclaim/dt-pvc created
# 查看结果状态
[root@master-01 gluster]# kubectl get pv,pvc
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
persistentvolume/test-pv 2Gi RWX Recycle Bound default/test-pvc 50s
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
persistentvolumeclaim/test-pvc Bound test-pv 2Gi RWX 50s
创建pod
# 编排
[root@master-01 gluster]# cat ng-deploy.yaml
---
apiVersion: apps/v1beta1
kind: Deployment
metadata:
labels:
run: nginx01
name: nginx01
spec:
replicas: 1
selector:
matchLabels:
app: nginx-pod1
template:
metadata:
labels:
app: nginx-pod1
spec:
containers:
- name: nginx11
image: nginx
imagePullPolicy: Always
volumeMounts:
- mountPath: /usr/share/nginx/html # 挂载到容器的路径
name: glu
restartPolicy: Always
volumes:
- name: glu 定义卷
persistentVolumeClaim:
claimName: test-pvc 使用pvc
---
apiVersion: v1
kind: Service
metadata:
labels:
app: nginx1
name: nginx1
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
nodePort: 30003
selector:
app: nginx-pod1
type: NodePort
# 创建
[root@master-01 gluster]# kubectl apply -f ng-deploy.yaml
deployment.apps/nginx01 created
service/nginx1 created
查看状态
[root@master-01 gluster]# kubectl get pod,svc|grep nginx
pod/nginx01-7df547bf8c-cxvht 1/1 Running 0 10m
service/nginx1 NodePort 10.254.55.187 <none> 80:30003/TCP 79m
[root@master-01 gluster]# kubectl describe po nginx01-7df547bf8c-cxvht
Name: nginx01-7df547bf8c-cxvht
......
Volumes:
glu:
Type: PersistentVolumeClaim (a reference to a PersistentVolumeClaim in the same namespace)
ClaimName: test-pvc
ReadOnly: false
default-token-tb5bg:
Type: Secret (a volume populated by a Secret)
SecretName: default-token-tb5bg
测试
在glusterfs存储卷中创建index.html,并写入内容
[root@master-01 gluster]# vi /opt/data/gv0/index.html
[root@master-01 gluster]# kubectl exec -ti nginx01-7df547bf8c-cxvht bash
root@nginx01-7df547bf8c-cxvht:/# ls /usr/share/nginx/html/
index.html
root@nginx01-7df547bf8c-cxvht:/# cat /usr/share/nginx/html/index.html
<h1>hello glusterfs</h1>
浏览器访问测试
现在就算pod 挂了等情况，数据也不会丢的，需要注意的是，上GlusterFS 一定得有人技术兜底，不然出了问题很麻烦的。
