一、概述

MySQL是一个关系型数据库管理系统，由瑞典MySQL AB 公司开发，属于 Oracle 旗下产品。MySQL 是最流行的关系型数据库管理系统之一，在 WEB 应用方面，MySQL是最好的 RDBMS (Relational Database Management System，关系数据库管理系统) 应用软件之一。这里主要讲mysql部署在k8s上，mysql部署在k8s上的优势主要有以下几点：

• 资源隔离
• 动态弹性扩缩容
• 环境一致性
• 运维方便

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二、开始部署（一主两从）

image.png

1）添加源

helm repo add bitnami https://charts.bitnami.com/bitnami
helm pull bitnami/mysql
tar -xf mysql-9.3.3.tgz

2）修改配置

• 修改mysql/values.yaml

...

image:
  registry: myharbor.com
  repository: bigdata/mysql
  tag: 8.0.30-debian-11-r15

...

architecture: replication

...

primary:
  persistence:
    enabled: true
    size: 10Gi
    storageClass: "mysql-local-storage"
    # 目录需要提前在宿主机上创建
    local:
    - name: mysql-0
      host: "local-168-182-110"
      path: "/opt/bigdata/servers/mysql/data/data1"
  service:
    type: NodePort
    nodePorts:
      mysql: "30306"

secondary:
  replicaCount: 2
  persistence:
    enabled: true
    size: 10Gi
    storageClass: "mysql-local-storage"
    # 目录需要提前在宿主机上创建
    local:
    - name: mysql-1
      host: "local-168-182-111"
      path: "/opt/bigdata/servers/mysql/data/data1"
    - name: mysql-2
      host: "local-168-182-112"
      path: "/opt/bigdata/servers/mysql/data/data1"
  service:
    type: NodePort
    nodePorts:
      mysql: "30307"

...

metrics:
  ## @param metrics.enabled Start a side-car prometheus exporter
  ##
  enabled: true
  image:
    registry: myharbor.com
    repository: bigdata/mysqld-exporter
    tag: 0.14.0-debian-11-r33

• 添加mysql/templates/pv.yaml

{{- range .Values.primary.persistence.local }}
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: {{ .name }}
  labels:
    name: {{ .name }}
spec:
  storageClassName: {{ $.Values.primary.persistence.storageClass }}
  capacity:
    storage: {{ $.Values.primary.persistence.size }}
  accessModes:
    - ReadWriteOnce
  local:
    path: {{ .path }}
  nodeAffinity:
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:
                - {{ .host }}
---
{{- end }}

{{- range .Values.secondary.persistence.local }}
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: {{ .name }}
  labels:
    name: {{ .name }}
spec:
  storageClassName: {{ $.Values.secondary.persistence.storageClass }}
  capacity:
    storage: {{ $.Values.secondary.persistence.size }}
  accessModes:
    - ReadWriteOnce
  local:
    path: {{ .path }}
  nodeAffinity:
    required:
      nodeSelectorTerms:
        - matchExpressions:
            - key: kubernetes.io/hostname
              operator: In
              values:
                - {{ .host }}
---
{{- end }}

• 添加mysql/templates/storage-class.yaml

kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: {{ .Values.primary.persistence.storageClass }}
provisioner: kubernetes.io/no-provisioner

3）开始安装

# 创建持久化目录
mkdir -p /opt/bigdata/servers/mysql/data/data1

# 先准备好镜像
docker pull docker.io/bitnami/mysql:8.0.30-debian-11-r15
docker tag docker.io/bitnami/mysql:8.0.30-debian-11-r15 myharbor.com/bigdata/mysql:8.0.30-debian-11-r15
docker push myharbor.com/bigdata/mysql:8.0.30-debian-11-r15

# mysqld-exporter
docker pull docker.io/bitnami/mysqld-exporter:0.14.0-debian-11-r33
docker tag docker.io/bitnami/mysqld-exporter:0.14.0-debian-11-r33 myharbor.com/bigdata/mysqld-exporter:0.14.0-debian-11-r33
docker push myharbor.com/bigdata/mysqld-exporter:0.14.0-debian-11-r33

# 开始安装
helm install mysql ./mysql -n mysql --create-namespace

NOTES

NAME: mysql
LAST DEPLOYED: Mon Sep 19 23:57:18 2022
NAMESPACE: mysql
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
CHART NAME: mysql
CHART VERSION: 9.3.3
APP VERSION: 8.0.30

** Please be patient while the chart is being deployed **

Tip:

  Watch the deployment status using the command: kubectl get pods -w --namespace mysql

Services:

  echo Primary: mysql-primary.mysql.svc.cluster.local:3306
  echo Secondary: mysql-secondary.mysql.svc.cluster.local:3306

Execute the following to get the administrator credentials:

  echo Username: root
  MYSQL_ROOT_PASSWORD=$(kubectl get secret --namespace mysql mysql -o jsonpath="{.data.mysql-root-password}" | base64 -d)

To connect to your database:

  1. Run a pod that you can use as a client:

      kubectl run mysql-client --rm --tty -i --restart='Never' --image  myharbor.com/bigdata/mysql:8.0.30-debian-11-r15 --namespace mysql --env MYSQL_ROOT_PASSWORD=$MYSQL_ROOT_PASSWORD --command -- bash

  2. To connect to primary service (read/write):

      mysql -h mysql-primary.mysql.svc.cluster.local -uroot -p"$MYSQL_ROOT_PASSWORD"

  3. To connect to secondary service (read-only):

      mysql -h mysql-secondary.mysql.svc.cluster.local -uroot -p"$MYSQL_ROOT_PASSWORD"



To access the MySQL Prometheus metrics from outside the cluster execute the following commands:

    kubectl port-forward --namespace mysql svc/mysql-metrics 9104:9104 &
    curl http://127.0.0.1:9104/metrics

image.png

查看pod状态

kubectl get pods,svc -n mysql -owide

image.png

4）测试验证

【温馨提示】从库（slave）是只读的。就是简单的读写测试，还有就是pod挂了，能否正常拉起等等。这个测试验证比较简单。这里就不一步步的演示了。

5）Prometheus监控

Prometheus：https://prometheus.k8s.local/targets?search=mysql

image.png

可以通过命令查看采集数据

kubectl get --raw http://10.244.0.74:9104/metrics
kubectl get --raw http://10.244.1.125:9104/metrics
kubectl get --raw http://10.244.2.178:9104/metrics

Grafana：https://grafana.k8s.local/
账号：admin，密码通过下面命令获取

kubectl get secret --namespace grafana grafana -o jsonpath="{.data.admin-password}" | base64 --decode ; echo

导入grafana模板，集群资源监控：7362
官方模块下载地址：https://grafana.com/grafana/dashboards/

image.png

6）卸载

helm uninstall mysql -n mysql 

kubectl delete pod -n mysql `kubectl get pod -n mysql |awk 'NR>1{print $1}'` --force
kubectl patch ns mysql -p '{"metadata":{"finalizers":null}}'
kubectl delete ns mysql --force

这里只是实现了mysql 的主从，没有实现高可用，官方目前没有出mysql ok k8s高可用的实现方案，虽然网上也有高可用的实现方案，但是我们公司没真正去落地使用，所以不予评价网上的高可用的方案，有兴趣的小伙伴可以去试试，其实mysql在大数据领域一般只是作为元数据存储，主挂了，影响不是很大。目前也在研究mysql on k8s 的高可用实现方案，如果后期有mysql on k8s高可用真正落地到生产环境中使用，到时候再来分享一下。MySQL on k8s 环境部署就先这里了，有疑问的小伙伴欢迎给我留言~