CentOS7下配置GlusterFS供Kubernetes使用

CentOS7下配置GlusterFS供Kubernetes使用

[TOC]

1. 环境说明

系统：CentOS7，/data为非系统分区挂载目录
docker：1.13.1
kubernetes：1.11.1
glusterfs：4.1.2

2. GlusterFS部署

2个节点，192.168.105.9七、192.168.105.98

使用yum安装

yum install centos-release-gluster
yum -y install glusterfs glusterfs-fuse glusterfs-server

CentOS-Gluster-4.1.repo

启动及设置开机启动

systemctl start glusterd 
systemctl enable glusterd

GlusterFS经过24007端口相互通讯。防火墙须要开放端口。

/etc/hosts

127.0.0.1   localhost localhost.localdomain localhost4 localhost4.localdomain4
::1         localhost localhost.localdomain localhost6 localhost6.localdomain6

# k8s 
192.168.105.92 lab1  # master1
192.168.105.93 lab2  # master2
192.168.105.94 lab3  # master3
192.168.105.95 lab4  # node4
192.168.105.96 lab5  # node5

# glusterfs
192.168.105.98 glu1  # glusterfs1
192.168.105.97 harbor1  # harbor1

在主机glu1上执行

#添加节点到集群执行操做的本机不须要probe本机
gluster peer probe harbor1

查看集群状态（节点间相互看到对方信息）

gluster peer status

Number of Peers: 1

Hostname: harbor1
Uuid: ebedc57b-7c71-4ecb-b92e-a7529b2fee31
State: Peer in Cluster (Connected)

GlusterFS 几种volume模式说明：
连接中比较直观：https://docs.gluster.org/en/latest/Administrator%20Guide/Setting%20Up%20Volumes/

1. 默认模式，既DHT, 也叫分布卷: 将文件已hash算法随机分布到 一台服务器节点中存储。
   命令格式：gluster volume create test-volume server1:/exp1 server2:/exp2
2. 复制模式，既AFR, 建立volume 时带 replica x 数量: 将文件复制到 replica x 个节点中，如今已经推荐3节点仲裁者复制模式，由于2节点可能产生脑裂。
   命令格式：gluster volume create test-volume replica 2 transport tcp server1:/exp1 server2:/exp2
gluster volume create test-volume replica 3 arbiter 1 transport tcp server1:/exp1 server2:/exp2 server3:/exp3
3. 分布式复制模式，至少4节点。
   命令格式：gluster volume create test-volume replica 2 transport tcp server1:/exp1 server2:/exp2 server3:/exp3 server4:/exp4
4. 分散模式，最少须要3节点
   命令格式：gluster volume create test-volume disperse 3 server{1..3}:/bricks/test-volume
5. 分布式分散模式，建立一个分布式分散体积,分散关键字和<数量>是强制性的，指定的砖块在命令行中的数量必须是分散数的倍数
   命令格式：gluster volume create <volname> disperse 3 server1:/brick{1..6}

gluster volume create k8s_volume 192.168.105.98:/data/glusterfs/dev/k8s_volume
gluster volume start k8s_volume
gluster volume status
gluster volume info

列一些Glusterfs调优：

# 开启 指定 volume 的配额
gluster volume quota k8s-volume enable
# 限制 指定 volume 的配额
gluster volume quota k8s-volume limit-usage / 1TB
# 设置 cache 大小, 默认32MB
gluster volume set k8s-volume performance.cache-size 4GB
# 设置 io 线程, 太大会致使进程崩溃
gluster volume set k8s-volume performance.io-thread-count 16
# 设置 网络检测时间, 默认42s
gluster volume set k8s-volume network.ping-timeout 10
# 设置 写缓冲区的大小, 默认1M
gluster volume set k8s-volume performance.write-behind-window-size 1024MB

3. 客户端使用GlusterFS

###3.1 物理机上使用GlusterFS的volume

yum install -y centos-release-gluster
yum install -y glusterfs glusterfs-fuse fuse fuse-libs openib libibverbs
mkdir -p /tmp/test
mount -t glusterfs 192.168.105.98:k8s_volume/tmp/test  # 和NFS挂载用法相似

3.2 Kubernetes使用GlusterFS

如下操做在kubernetes master节点操做

3.2.1 建立GlusterFS端点定义

vim /etc/kubernetes/glusterfs/glusterfs-endpoints.json

{
  "kind": "Endpoints",
  "apiVersion": "v1",
  "metadata": {
    "name": "glusterfs-cluster"
  },
  "subsets": [
    {
      "addresses": [
        {
          "ip": "192.168.105.98"
        }
      ],
      "ports": [
        {
          "port": 1
        }
      ]
    },
    {
      "addresses": [
        {
          "ip": "192.168.105.97"
        }
      ],
      "ports": [
        {
          "port": 1
        }
      ]
    }
  ]
}

注意：
该subsets字段应填充GlusterFS集群中节点的地址。能够在port字段中提供任何有效值（从1到65535）。

kubectl apply -f /etc/kubernetes/glusterfs/glusterfs-endpoints.json
kubectl get endpoints

NAME                ENDPOINTS                                                     AGE
glusterfs-cluster   192.168.105.97:1,192.168.105.98:1

3.2.2 配置 service

咱们还须要为这些端点建立服务，以便它们可以持久存在。咱们将在没有选择器的状况下添加此服务，以告知Kubernetes咱们想要手动添加其端点

vim glusterfs-service.json

{
  "kind": "Service",
  "apiVersion": "v1",
  "metadata": {
    "name": "glusterfs-cluster"
  },
  "spec": {
    "ports": [
      {"port": 1}
    ]
  }
}

kubectl apply -f glusterfs-service.json

3.3.3 配置PersistentVolume

建立glusterfs-pv.yaml文件，指定storage容量和读写属性

vim glusterfs-pv.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv001
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  glusterfs:
    endpoints: "glusterfs-cluster"
    path: "k8s_volume"
    readOnly: false

kubectl apply -f glusterfs-pv.yaml 
kubectl get pv

NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM     STORAGECLASS   REASON    AGE
pv001     10Gi       RWX            Retain           Available                                      21s

3.3.4 配置PersistentVolumeClaim

建立glusterfs-pvc.yaml文件，指定请求资源大小

vim glusterfs-pvc.yaml

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv001
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  glusterfs:
    endpoints: "glusterfs-cluster"
    path: "k8s_volume"
    readOnly: false

kubectl apply -f glusterfs-pvc.yaml
kubectl get pvc

NAME      STATUS    VOLUME    CAPACITY   ACCESS MODES   STORAGECLASS   AGE
pvc001    Bound     zk001     10Gi       RWX                           44s

3.3.5 部署应用挂载pvc

以建立nginx，把pvc挂载到容器内的/usr/share/nginx/html文件夹为例：

vim glusterfs-nginx-deployment.yaml

apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
  name: nginx-dm
  namespace: default
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 2 # tells deployment to run 2 pods matching the template
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
          - containerPort: 80
        volumeMounts:
          - name: storage001
            mountPath: "/usr/share/nginx/html"
      volumes:
        - name: storage001
          persistentVolumeClaim:
            claimName: pvc001

kubectl create -f nginx_deployment.yaml
# 查看部署是否成功
kubectl get pod|grep nginx-dm

nginx-dm-c8c895d96-hfdsz            1/1       Running   0          36s
nginx-dm-c8c895d96-jrfbx            1/1       Running   0          36s

验证结果：

# 查看挂载
[root@lab1 glusterfs]# kubectl exec -it nginx-dm-c8c895d96-5h649 -- df -h|grep nginx
192.168.105.97:k8s_volume 1000G   11G  990G   2% /usr/share/nginx/html
[root@lab1 glusterfs]# kubectl exec -it nginx-dm-c8c895d96-zf6ch -- df -h|grep nginx
192.168.105.97:k8s_volume 1000G   11G  990G   2% /usr/share/nginx/html
[root@lab1 glusterfs]# kubectl exec -it nginx-dm-c8c895d96-5h649 -- touch /usr/share/nginx/html/ygqygq2      
[root@lab1 glusterfs]# kubectl exec -it nginx-dm-c8c895d96-5h649 -- ls -lt /usr/share/nginx/html/
total 1
-rw-r--r--. 1 root root 4 Aug 13 09:43 ygqygq2
-rw-r--r--. 1 root root 5 Aug 13 09:34 ygqygq2.txt
[root@lab1 glusterfs]# kubectl exec -it nginx-dm-c8c895d96-zf6ch -- ls -lt /usr/share/nginx/html/
total 1
-rw-r--r--. 1 root root 4 Aug 13 09:43 ygqygq2
-rw-r--r--. 1 root root 5 Aug 13 09:34 ygqygq2.txt

至此部署完成。

4. 小结

此文GlusterFS是安装在物理系统下，而非kubernetes中，全部须要手工维护，下次介绍在kubernetes中安装使用gluster。GlusterFS的volume模式根据业务灵活应用。须要注意的是，若是使用分布卷，pod中的挂载目录文件可能存在卷的任一节点中，可能并不是直接df -h看到的那个节点中。

参数资料：
[1] https://kubernetes.io/docs/concepts/storage/persistent-volumes/
[2] https://kubernetes.io/docs/tasks/configure-pod-container/configure-persistent-volume-storage/
[3] https://www.kubernetes.org.cn/4069.html
[4] https://www.gluster.org/
[5] http://www.javashuo.com/article/p-dsnctvhn-sw.html
[6] https://docs.gluster.org/en/latest/Administrator%20Guide/Setting%20Up%20Volumes/
[7] https://docs.gluster.org/en/latest/Administrator%20Guide/Setting%20Up%20Clients/
[8] https://github.com/kubernetes/examples/blob/master/staging/volumes/glusterfs/README.md