13.kubernetes之pv，pvc，configmap（带补充实例）

管理存储是管理计算的一个明显问题。该PersistentVolume子系统为用户和管理员提供了一个API，用于抽象如何根据消费方式提供存储的详细信息。为此，我们引入了两个新的API资源：PersistentVolume和PersistentVolumeClaim。

A PersistentVolume（PV）是群集中由管理员配置的一块存储。它是集群中的资源，就像节点是集群资源一样。PV是容量插件，如Volumes，但其生命周期独立于使用PV的任何单个pod。此API对象捕获存储实现的详细信息，包括NFS，iSCSI或特定于云提供程序的存储系统。

注意 pv 不是一个namespace资源  pv是跨namespace的共享对象，pvc是有namespace特征的

甲PersistentVolumeClaim（PVC）是由用户进行存储的请求。它类似于一个吊舱。Pod消耗节点资源，PVC消耗PV资源。Pod可以请求特定级别的资源（CPU和内存）。声明可以请求特定的大小和访问模式（例如，可以mounted once read/write or many times read-only）。

虽然PersistentVolumeClaims允许用户使用抽象存储资源，但是PersistentVolumes对于不同的问题，用户通常需要具有不同属性（例如性能）。群集管理员需要能够提供各种PersistentVolumes不同的方式，而不仅仅是大小和访问模式，而不会让用户了解这些卷的实现方式。对于这些需求，有StorageClass 资源。

创建PV（使用nfs方式或者local）这里使用nfs方式 手动供给方式很low

安装配置nfs服务器
[root@nlp-node1 3]# yum install nfs-utils rpcbind -y
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * extras: mirrors.huaweicloud.com
 * updates: mirrors.huaweicloud.com
软件包 1:nfs-utils-1.3.0-0.61.el7.x86_64 已安装并且是最新版本
软件包 rpcbind-0.2.0-47.el7.x86_64 已安装并且是最新版本
无须任何处理
---------------------------------------------------
[root@nlp-node1 3]# vim /etc/exports
[root@nlp-node1 3]# cat /etc/exports
/kube_pv *(rw,sync,all_squash)
[root@nlp-node1 3]# systemctl start nfs.service  rpcbind.service
[root@nlp-node1 3]# mkdir -pv /kube_pv
mkdir: 已创建目录 "/kube_pv"
[root@nlp-node1 3]# chown nfsnobody /kube_pv -R 

创建pv

[root@master pvc]# cat pv.ymal 
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv-test
namespace: default
spec:
capacity:
storage: 5Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: slow
nfs:
path: /kube_pv
server: 10.24.2.125

[root@master pvc]# kubectl create -f pv.ymal

[root@master pvc]# kubectl describe pv 
Name: pv-test
Labels: <none>
Annotations: <none>
Finalizers: [kubernetes.io/pv-protection]
StorageClass: slow
Status: Available
Claim: 
Reclaim Policy: Recycle
Access Modes: RWO
VolumeMode: Filesystem
Capacity: 5Gi
Node Affinity: <none>
Message: 
Source:
Type: NFS (an NFS mount that lasts the lifetime of a pod)
Server: 10.24.2.125
Path: /kube_pv
ReadOnly: false
Events: <none>
[root@master pvc]# cat pv.ymal 
apiVersion: v1
kind: PersistentVolume
metadata:
name: pv-test
namespace: default
spec:
capacity:
storage: 5Gi
volumeMode: Filesystem
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Recycle
storageClassName: slow
nfs:
path: /kube_pv
server: 10.24.2.125

创建pvc

[root@master pvc]# cat pvc.ymal 
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
name: myclaim
labels:
song: lele
spec:
accessModes:
- ReadWriteOnce
volumeMode: Filesystem
volumeName: pv-test
resources:
limits:
storage: 2Gi
requests:
storage: 2Gi
storageClassName: slow
selector:
matchLabels:
release: "stable"
matchExpressions:
- {key: environment, operator: In, values: [dev]}

configMap 一个特殊的数据卷，用来管理你的pod

命令行创建一个configMap
[root@master song]# kubectl create configmap nginx-config --from-literal=nginx_port= --from-literal=server_name=www.slele.com
configmap/nginx-config created
[root@master song]# kubectl get  configmaps -o yaml
apiVersion: v1
items:
- apiVersion: v1
  data:
    nginx_port: ""
    server_name: www.slele.com
  kind: ConfigMap
  metadata:
    creationTimestamp: "2019-03-09T05:12:39Z"
    name: nginx-config
    namespace: default
    resourceVersion: ""
    selfLink: /api/v1/namespaces/default/configmaps/nginx-config
    uid: f5832bc1--11e9-bc53-52540062b2ca
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""

[root@master song]# kubectl describe configmaps nginx-config
Name: nginx-config
Namespace: default
Labels: <none>
Annotations: <none>

Data
====
nginx_port:
----
80
server_name:
----
www.slele.com
Events: <none>

将文件整体作为一个键值创建一个configmap

[root@master song]# kubectl create configmap nginx-file --from-file=/etc/nginx/nginx.conf
configmap/nginx-file created
[root@master song]# kubectl describe configmaps nginx-file
Name:         nginx-file
Namespace:    default
Labels:       <none>
Annotations:  <none>

Data
====
nginx.conf:
----
# For more information on configuration, see:
#   * Official English Documentation: http://nginx.org/en/docs/
#   * Official Russian Documentation: http://nginx.org/ru/docs/

user nginx;
worker_processes auto;
error_log /var/log/nginx/error.log;
pid /run/nginx.pid;

# Load dynamic modules. See /usr/share/nginx/README.dynamic.
include /usr/share/nginx/modules/*.conf;

events {
    worker_connections 1024;
}

http {
    log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
                      '$status $body_bytes_sent "$http_referer" '
                      '"$http_user_agent" "$http_x_forwarded_for"';

    access_log  /var/log/nginx/access.log  main;

    sendfile            on;
    tcp_nopush          on;
    tcp_nodelay         on;
    keepalive_timeout   65;
    types_hash_max_size 2048;

    include             /etc/nginx/mime.types;
    default_type        application/octet-stream;

    # Load modular configuration files from the /etc/nginx/conf.d directory.
    # See http://nginx.org/en/docs/ngx_core_module.html#include
    # for more information.
    include /etc/nginx/conf.d/*.conf;

    server {
        listen       80 default_server;
        listen       [::]:80 default_server;
        server_name  _;
        root         /usr/share/nginx/html;

        # Load configuration files for the default server block.
        include /etc/nginx/default.d/*.conf;

        location / {
        }

        error_page 404 /404.html;
            location = /40x.html {
        }

        error_page 500 502 503 504 /50x.html;
            location = /50x.html {
        }
    }

# Settings for a TLS enabled server.
#
#    server {
#        listen       443 ssl http2 default_server;
#        listen       [::]:443 ssl http2 default_server;
#        server_name  _;
#        root         /usr/share/nginx/html;
#
#        ssl_certificate "/etc/pki/nginx/server.crt";
#        ssl_certificate_key "/etc/pki/nginx/private/server.key";
#        ssl_session_cache shared:SSL:1m;
#        ssl_session_timeout  10m;
#        ssl_ciphers HIGH:!aNULL:!MD5;
#        ssl_prefer_server_ciphers on;
#
#        # Load configuration files for the default server block.
#        include /etc/nginx/default.d/*.conf;
#
#        location / {
#        }
#
#        error_page 404 /404.html;
#            location = /40x.html {
#        }
#
#        error_page 500 502 503 504 /50x.html;
#            location = /50x.html {
#        }
#    }

}

Events:  <none>