Ceph+K8s 中间件实战 | 第 4 天：K8s 部署 MySQL 高可用集群（Ceph RBD 持久化 + 架构设计 + 登录巡检）

应用 Pod → ClusterIP Service → MySQL Primary（写）

↓ Binlog Replication

MySQL Secondary-0（读）

MySQL Secondary-1（读）

Primary PVC ←→ Ceph RBD Image ←→ Ceph OSD Pool

Secondary PVC ←→ Ceph RBD Image ←→ Ceph OSD Pool

# 添加 Bitnami 官方 Chart 仓库

helm repo add bitnami https://charts.bitnami.com/bitnami

# 更新本地 Chart 索引

helm repo update

# 搜索 mysql chart 确认可用

helm search repo bitnami/mysql

# 查看 chart 版本信息

helm show chart bitnami/mysql

# mysql-values.yaml — Ceph RBD 持久化 MySQL 集群配置

architecture: replication # 主从复制模式

primary:

persistence:

enabled: true

storageClass: "ceph-rbd-sc" # 对接 Day 2 创建的 Ceph RBD StorageClass

accessModes:

– ReadWriteOnce

size: 20Gi

resources:

requests:

cpu: "500m"

memory: "512Mi"

limits:

cpu: "2000m"

memory: "2Gi"

mysqlUser: "appuser"

mysqlDatabase: "appdb"

secondary:

replicaCount: 2 # 2 个从节点

persistence:

enabled: true

storageClass: "ceph-rbd-sc"

accessModes:

– ReadWriteOnce

size: 20Gi

resources:

requests:

cpu: "500m"

memory: "512Mi"

limits:

cpu: "2000m"

memory: "2Gi"

auth:

rootPassword: "Ceph@K8s#2026" # 生产环境建议使用 Secret 注入

replicationPassword: "Repl#Pass2026"

metrics:

enabled: true # 开启 Prometheus 指标暴露

serviceMonitor:

enabled: false # 如已安装 Prometheus Operator 可开启

# 创建独立命名空间

kubectl create namespace middleware

# 部署 MySQL 集群

helm install mysql bitnami/mysql

–namespace middleware

-f mysql-values.yaml

–version 11.x.x

# 查看 Helm Release 状态

helm list -n middleware

# 等待 Pod 就绪（通常需要 1-3 分钟）

kubectl wait –for=condition=Ready pods -n middleware -l app.kubernetes.io/instance=mysql –timeout=300s

# 查看 Pod 运行状态，确认 primary 和 secondary 全部 Running

kubectl get pods -n middleware -l app.kubernetes.io/instance=mysql -o wide

# 查看 Service 列表

kubectl get svc -n middleware -l app.kubernetes.io/instance=mysql

# 查看 PVC 绑定情况，确认 STORAGECLASS 为 ceph-rbd-sc

kubectl get pvc -n middleware -l app.kubernetes.io/instance=mysql

NAME READY STATUS RESTARTS AGE

mysql-primary-0 1/1 Running 0 3m

mysql-secondary-0 1/1 Running 0 2m

mysql-secondary-1 1/1 Running 0 2m

NAME TYPE CLUSTER-IP PORT(S) AGE

mysql-primary ClusterIP 10.96.23.45 3306/TCP 3m

mysql-secondary ClusterIP 10.96.23.67 3306/TCP 3m

mysql-primary-hl ClusterIP None 3306/TCP 3m

mysql-secondary-hl ClusterIP None 3306/TCP 3m

NAME STATUS VOLUME CAPACITY STORAGECLASS AGE

data-mysql-primary-0 Bound pvc-xxxx 20Gi ceph-rbd-sc 3m

data-mysql-secondary-0 Bound pvc-yyyy 20Gi ceph-rbd-sc 2m

data-mysql-secondary-1 Bound pvc-zzzz 20Gi ceph-rbd-sc 2m

# 获取 root 密码

ROOT_PASSWORD=$(kubectl get secret –namespace middleware mysql -o jsonpath="{.data.mysql-root-password}" | base64 -d)

# 进入 Primary Pod 执行 MySQL 客户端

kubectl exec -it -n middleware mysql-primary-0 —

mysql -uroot -p"$ROOT_PASSWORD"

# 在 MySQL 命令行中验证主从复制状态

— 在 Primary 节点执行，查看 Binlog 位置

SHOW MASTER STATUS;

— 查看从节点连接信息

SELECT host, user, port FROM mysql.user WHERE user='monitor' OR user='replicator';

— 在 Secondary 节点执行，查看复制状态

SHOW REPLICA STATUSG

— 关键指标确认：

— Slave_IO_Running: Yes

— Slave_SQL_Running: Yes

— Seconds_Behind_Master: 0

— 创建测试数据库验证数据同步

CREATE DATABASE IF NOT EXISTS test_ha;

USE test_ha;

CREATE TABLE t1 (id INT PRIMARY KEY, msg VARCHAR(100));

INSERT INTO t1 VALUES (1, 'Ceph RBD MySQL HA Test');

— 切换到 Secondary Pod 验证数据已同步

— kubectl exec -it -n middleware mysql-secondary-0 — mysql -uroot -p"$ROOT_PASSWORD" -e "SELECT * FROM test_ha.t1;"

# 端口转发到本地验证（临时调试）

kubectl port-forward -n middleware svc/mysql-primary 3306:3306 &

# 使用本地 MySQL 客户端连接

mysql -h 127.0.0.1 -P 3306 -uroot -p"$ROOT_PASSWORD" -e "SELECT @@hostname, @@version;"

— 确认连接到 Primary 节点，版本号正确

# 检查所有 Pod 状态及运行时间

kubectl get pods -n middleware -l app.kubernetes.io/instance=mysql

# 检查 Pod 详细事件（排查启动失败）

kubectl describe pod -n middleware mysql-primary-0

# 检查 PVC 绑定状态与容量

kubectl get pvc -n middleware -l app.kubernetes.io/instance=mysql

# 检查 Ceph RBD Image 是否在 Ceph 端正常创建

# 在 Ceph 容器或节点上执行

rbd ls -p k8s-rbd-pool | grep mysql

# 查看 Primary 节点 MySQL 日志（错误日志）

kubectl logs -n middleware mysql-primary-0 –tail=100

# 查看 Secondary 节点日志

kubectl logs -n middleware mysql-secondary-0 –tail=100

# 实时跟踪日志输出

kubectl logs -n middleware mysql-primary-0 -f

# 查看 Helm Release 部署历史

helm history mysql -n middleware

# 进入 MySQL 查看连接数与运行线程

kubectl exec -it -n middleware mysql-primary-0 —

mysql -uroot -p"$ROOT_PASSWORD" -e "

SHOW STATUS LIKE 'Threads_connected';

SHOW STATUS LIKE 'Slow_queries';

SHOW STATUS LIKE 'Innodb_buffer_pool_wait_free';

SHOW VARIABLES LIKE 'max_connections';

"

# 查看 MySQL 复制延迟

kubectl exec -it -n middleware mysql-secondary-0 —

mysql -uroot -p"$ROOT_PASSWORD" -e "SHOW REPLICA STATUSG" |

grep -E "Seconds_Behind_Master|Slave_IO_Running|Slave_SQL_Running"

# 查看 PVC 实际使用量（需要 metrics-server）

kubectl get pvc -n middleware -l app.kubernetes.io/instance=mysql

-o custom-columns=NAME:.metadata.name,STATUS:.status.phase,CAPACITY:.status.capacity.storage

# 在 MySQL 内查看数据库大小

kubectl exec -it -n middleware mysql-primary-0 —

mysql -uroot -p"$ROOT_PASSWORD" -e "

SELECT table_schema AS 'Database',

ROUND(SUM(data_length+index_length)/1024/1024, 2) AS 'Size (MB)'

FROM information_schema.tables

GROUP BY table_schema;

"

# 在 Ceph 端查看 Pool 容量使用

# ceph df | grep k8s-rbd-pool