K8S/Kubernetes

1.storageclass(存储类)概念

storageclass是一个存储类，k8s集群管理员通过创建storageclass可以动态生成一个存储卷供k8s用户使用。

2.storageclass资源定义

每个StorageClass都包含字段provisioner，parameters和reclaimPolicy，当需要动态配置属于该类的PersistentVolume时使用这些字段。

StorageClass对象的名称很重要，是用户可以请求特定类的方式。管理员在首次创建StorageClass对象时设置类的名称和其他参数，并且在创建对象后无法更新这些对象。

管理员可以为不请求任何特定类绑定的PVC指定默认的StorageClass

(1)yaml文件示例说明：

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: standard
provisioner: kubernetes.io/aws-ebs
parameters:
  type: gp2
reclaimPolicy: Retain
mountOptions:
  - debug
volumeBindingMode: Immediate

(2)Provisioner

storageclass需要有一个供应者，用来确定我们使用什么样的存储来创建pv

常见的provisioner供应者如下：

provisioner既可以是内部供应程序，也可以由外部供应商提供，如果是外部供应商可以参考https://github.com/kubernetes-incubator/external-storage/下提供的方法创建storageclass的provisioner，例如，NFS不提供内部配置程序，但可以使用外部配置程序。一些外部供应商列在存储库https://github.com/kubernetes-incubator/external-storage下。

nfs的provisioner：

https://github.com/kubernetes-incubator/external-storage/tree/master/nfs/deploy/kubernetes

Reclaim Policy

由存储类动态创建持久化存储卷(pv)时可以指定reclaimPolicy字段，这个字段中指定的回收策略可以是Delete或Retain。如果在创建StorageClass对象时未指定reclaimPolicy，则默认为Delete。

Mount Options(挂载选项)

如果Volume Plugin不支持这个挂载选项，但是指定了，就会使provisioner创建失败

Volume Binding Mode

这个字段用来说明什么时候进行卷绑定和动态配置；

默认情况下，立即模式表示一旦创建了PersistentVolumeClaim，就会发生卷绑定和动态配置。对于受拓扑约束且无法从群集中的所有节点全局访问的存储后端，将在不知道Pod的调度要求的情况下绑定或配置PersistentVolumes。这可能导致不可调度的Pod。

集群管理员可以通过指定WaitForFirstConsumer模式来解决此问题，该模式将延迟绑定和配置PersistentVolume，直到创建使用PersistentVolumeClaim的Pod。将根据Pod的调度约束指定的拓扑选择或配置PersistentVolumes。这些包括但不限于资源需求，节点选择器，pod亲和力和反亲和力，以及污点和容忍度。

通过nfs实现存储类的动态供给

1.安装nfs服务

选择自己的任意一台机器，我选择k8s的master1节点，对应的机器ip是192.168.0.6，在192.168.0.6上执行如下步骤，大家在自己环境找一台k8s节点的机器安装就可以了~

(1)yum安装nfs

yum install nfs-utils -y
systemctl start nfs
chkconfig nfs on

(2)在master1上创建一个nfs共享目录

mkdir  /data/nfs_pro   -p

#修改/etc/exports文件，把刚才生成的共享目录添加到这个文件里

cat  /etc/exports

 /data/nfs_pro    192.168.0.0/24(rw,no_root_squash)

让刚才配置文件生效

exportfs -arv  

systemctl restart nfs

(3)k8s的各个node节点也需要安装nfs

yum install nfs-utils -y
systemctl start nfs
chkconfig nfs on

2.创建运行nfs-provisioner的sa账号

cat  serviceaccount.yaml

apiVersion: v1
kind: ServiceAccount
metadata:
  name: nfs-provisioner

 通过kubectl更新yaml文件

kubectl apply -f serviceaccount.yaml

3.对sa账号做rbac授权

cat service-rbac.yaml

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: nfs-provisioner-runner
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", "endpoints"]
    verbs: ["get"]
  - apiGroups: ["extensions"]
    resources: ["podsecuritypolicies"]
    resourceNames: ["nfs-provisioner"]
    verbs: ["use"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: run-nfs-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-provisioner
    namespace: default
roleRef:
  kind: ClusterRole
  name: nfs-provisioner-runner
  apiGroup: rbac.authorization.k8s.io
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-provisioner
rules:
  - apiGroups: [""]
    resources: ["endpoints"]
    verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: leader-locking-nfs-provisioner
subjects:
  - kind: ServiceAccount
    name: nfs-provisioner
    namespace: default
roleRef:
  kind: Role
  name: leader-locking-nfs-provisioner
  apiGroup: rbac.authorization.k8s.io

 通过kubectl更新yaml文件

kubectl apply -f service-rbac.yaml

4.通过deployment创建pod用来运行nfs-provisioner

cat  deployment.yaml

kind: Deployment
apiVersion: apps/v1
metadata:
  name: nfs-provisioner
spec:
  selector:
    matchLabels:
      app: nfs-provisioner
  replicas: 1
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: nfs-provisioner
    spec:
      serviceAccount: nfs-provisioner
      containers:
        - name: nfs-provisioner
          image: registry.cn-hangzhou.aliyuncs.com/open-ali/nfs-client-provisioner:latest
          volumeMounts:
            - name: nfs-client-root
              mountPath: /persistentvolumes
          env:
            - name: PROVISIONER_NAME
              value: example.com/nfs
            - name: NFS_SERVER
              value: 192.168.0.6
            - name: NFS_PATH
              value: /data/storage
      volumes:
        - name: nfs-client-root
          nfs:
            server: 192.168.0.6
            path: /data/storage

 通过kubectl更新yaml文件

kubectl apply -f deployment.yaml

查看nfs provisioner的pod是否创建成功

kubectl get pods

显示如下，说明创建成功

NAME                               READY   STATUS    RESTARTS   AGE
nfs-provisioner-7d6859cc59-pzr7n   1/1     Running   0          72s

 创建storageclass

cat  class.yaml

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: nfs-storage
provisioner: example.com/nfs

通过kubectl更新yaml文件

kubectl apply -f class.yaml

查看storageclass是否创建成功

kubectl get storageclass

显示如下，说明创建成功

NAME          PROVISIONER       RECLAIMPOLICY   VOLUMEBINDINGMODE   ALLOWVOLUMEEXPANSION   AGE
nfs-storage   example.com/nfs   Delete          Immediate           false                  11h

 通过helm部署gitlab

1、解压gitlab-ce.tar.gz

tar zxvf gitlab-ce.tar.gz

2、进入到解压路径，通过helm安装gitlab、postgresql、redis

cd gitlab-ce

通过helm安装部署helm install .

查看是否部署成功

kubectl get pods

显示如下，看到STATUS都是running状态，说明部署成功

NAME                                             READY   STATUS    RESTARTS   AGE
alliterating-quail-gitlab-ce-756ddcb6d5-rwnzj    1/1     Running   0          3m56s
alliterating-quail-postgresql-68bc89cd7f-slt6g   1/1     Running   0          3m56s
alliterating-quail-redis-7954fbbfbc-5jqfx        1/1     Running   0          3m56s

 查看gitlab在宿主机暴露的端口

kubectl get svc | grep gitlab

alliterating-quail-gitlab-ce    NodePort    10.105.171.114   <none>        22:32503/TCP,80:31572/TCP,443:32

通过上面可以看到容器里的80端口在宿主机映射的端口是31572，所以浏览器访问k8s的master1节点ip:31572即可，我在浏览器访问如下地址：

192.168.0.6:31572

默认的用户名和密码分别是：

root

gitlab0920

输入用户名和密码之后即可登陆到gitlab的web界面

gitlab-ce.tar.gz里涉及的Chart文件说明讲解

 1.上面的压缩包解压之后，在gitlab-ce目录下，有个values.yaml文件，内容及解释如下

## GitLab CE image
## ref: https://hub.docker.com/r/gitlab/gitlab-ce/tags/
##
image: gitlab/gitlab-ce:10.6.2-ce.0
#gitlab使用的镜像，我们安装的是10版本

## Specify a imagePullPolicy
## 'Always' if imageTag is 'latest', else set to 'IfNotPresent'
## ref: http://kubernetes.io/docs/user-guide/images/#pre-pulling-images
##
# imagePullPolicy:
imagePullPolicy: IfNotPresent
#镜像拉取策略，IfNotPresent表示本地不存在，就从官方拉取

## The URL (with protocol) that your users will use to reach the install.
## ref: https://docs.gitlab.com/omnibus/settings/configuration.html#configuring-the-external-url-for-gitlab
##
externalUrl: http://gitlab.lucky.com/
#可访问的域名，这里我随便写了有一个，暂时用不到
## Change the initial default admin password if set. If not set, you'll be
## able to set it when you first visit your install.
##
gitlabRootPassword: "gitlab0920"
#登陆gitlab web界面的密码，可以随便写，符合密码复杂度即可
#登陆gitlab web界面的默认用户是root

## For minikube, set this to NodePort, elsewhere use LoadBalancer
## ref: http://kubernetes.io/docs/user-guide/services/#publishing-services---service-types
##
serviceType: NodePort
#service的类型，NodePort表示暴露出来的服务可以在k8s集群外部访问

## Ingress configuration options
##
ingress:
  annotations:
      # kubernetes.io/ingress.class: nginx
      # kubernetes.io/tls-acme: "true"
  enabled: false
  tls:
      # - secretName: gitlab.cluster.local
      #   hosts:
      #     - gitlab.cluster.local
  url: gitlab.cluster.local

#上面是ingress相关的，暂时我们用不到

## Configure external service ports
## ref: http://kubernetes.io/docs/user-guide/services/
sshPort: 22
#容器里暴露的22端口
httpPort: 80
#容器里暴露的80端口
httpsPort: 443
#容器里暴露的443端口
## livenessPort Port of liveness probe endpoint
livenessPort: http
## readinessPort Port of readiness probe endpoint
readinessPort: http

## Configure resource requests and limits
## ref: http://kubernetes.io/docs/user-guide/compute-resources/
##
resources:
  ## GitLab requires a good deal of resources. We have split out Postgres and
  ## redis, which helps some. Refer to the guidelines for larger installs.
  ## ref: https://docs.gitlab.com/ce/install/requirements.html#hardware-requirements
  requests:
    memory: 1Gi
    cpu: 500m
  limits:
    memory: 2Gi
    cpu: 1

## Enable persistence using Persistent Volume Claims
## ref: http://kubernetes.io/docs/user-guide/persistent-volumes/
## ref: https://docs.gitlab.com/ce/install/requirements.html#storage
##
persistence:
#下面配置的是跟持久化存储相关的内容
  ## This volume persists generated configuration files, keys, and certs.
  ##
  gitlabEtc:
    enabled: true
    size: 1Gi
    ## If defined, volume.beta.kubernetes.io/storage-class: <storageClass>
    ## Default: volume.alpha.kubernetes.io/storage-class: default
    ##
    storageClass: "nfs-storage"
#开启了storageclass，这里的storageclass是nfs-storage，
#就是我们上面创建的那个nfs-storage
    accessMode: ReadWriteOnce
#访问模式，单路独写
  ## This volume is used to store git data and other project files.
  ## ref: https://docs.gitlab.com/omnibus/settings/configuration.html#storing-git-data-in-an-alternative-directory
  ##
  gitlabData:
    enabled: true
    size: 10Gi
    ## If defined, volume.beta.kubernetes.io/storage-class: <storageClass>
    ## Default: volume.alpha.kubernetes.io/storage-class: default
    ##
    storageClass: "nfs-storage"
#开启了storageclass，这里的storageclass是nfs-storage，
#就是我们上面创建的那个nfs-storage
    accessMode: ReadWriteOnce
#访问模式，单路独写
## Configuration values for the postgresql dependency.
## ref: https://github.com/kubernetes/charts/blob/master/stable/postgresql/README.md
##
postgresql:
  # 9.6 is the newest supported version for the GitLab container
  imageTag: "9.6.5"
  cpu: 1000m
  memory: 1Gi

  postgresUser: gitlab
  postgresPassword: gitlab
  postgresDatabase: gitlab

  persistence:
    size: 10Gi
    storageClass: "nfs-storage"
## Configuration values for the redis dependency.
## ref: https://github.com/kubernetes/charts/blob/master/stable/redis/README.md
##
redis:
  redisPassword: "gitlab"

  resources:
    requests:
      memory: 1Gi

  persistence:
    size: 10Gi
    storageClass: "nfs-storage"
#开启了storageclass，这里的storageclass是nfs-storage，
#就是我们上面创建的那个nfs-storage

 原文：https://mp.weixin.qq.com/s/vOI1o7iH6gz4-aqwzZQyGQ