k8s mysql主从数据同步_【深入分析】K8s部署Mysql主从复制+读写分离

apiVersion: apps/v1

kind: StatefulSet

metadata:

name: mysql

spec:

selector:

matchLabels:

app: mysql

serviceName: mysql

replicas: 3

template:

metadata:

labels:

app: mysql

spec:

initContainers:

- name: init-mysql

image: mysql:5.7

imagePullPolicy: IfNotPresent

command:

- bash

- "-c"

- |set -ex

# 从hostname中获取索引，比如(mysql-1)会获取(1)

[[ `hostname` =~ -([0-9]+)$ ]] || exit 1

ordinal=${BASH_REMATCH[1]}

echo [mysqld] > /mnt/conf.d/server-id.cnf

# 为了不让server-id=0而增加偏移量

echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf

# 拷贝对应的文件到/mnt/conf.d/文件夹中

if [[ $ordinal -eq 0 ]]; then

cp /mnt/config-map/master.cnf /mnt/conf.d/

else

cp /mnt/config-map/slave.cnf /mnt/conf.d/

fi

volumeMounts:

- name: conf

mountPath: /mnt/conf.d

- name: config-map

mountPath: /mnt/config-map

- name: clone-mysql

image: twoeo/gcr.io-google-samples-xtrabackup:latest

imagePullPolicy: IfNotPresent

command:

- bash

- "-c"

- |set -ex

# 整体意思:

# 1.如果是主mysql中的xtrabackup,就不需要克隆自己了,直接退出

# 2.如果是从mysql中的xtrabackup,先判断是否是第一次创建，因为第二次重启本地就有数据库，无需克隆。若是第一次创建(通过/var/lib/mysql/mysql文件是否存在判断),就需要克隆数据库到本地。

# 如果有数据不必克隆数据，直接退出()

[[ -d /var/lib/mysql/mysql ]] && exit 0

# 如果是master数据也不必克隆

[[ `hostname` =~ -([0-9]+)$ ]] || exit 1

ordinal=${BASH_REMATCH[1]}

[[ $ordinal -eq 0 ]] && exit 0

# 从序列号比自己小一的数据库克隆数据，比如mysql-2会从mysql-1处克隆数据

ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql

# 比较数据

xtrabackup --prepare --target-dir=/var/lib/mysql

volumeMounts:

- name: data

mountPath: /var/lib/mysql

subPath: mysql

- name: conf

mountPath: /etc/mysql/conf.d

containers:

- name: mysql

image: mysql:5.7

imagePullPolicy: IfNotPresent

env:

- name: MYSQL_ALLOW_EMPTY_PASSWORD

value: "1"

ports:

- name: mysql

containerPort: 3306

volumeMounts:

- name: data

mountPath: /var/lib/mysql

subPath: mysql

- name: conf

mountPath: /etc/mysql/conf.d

resources:

requests:

cpu: 50m

memory: 50Mi

livenessProbe:

exec:

command: ["mysqladmin", "ping"]

initialDelaySeconds: 30

periodSeconds: 10

timeoutSeconds: 5

readinessProbe:

exec:

# Check we can execute queries over TCP (skip-networking is off).

command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]

initialDelaySeconds: 5

periodSeconds: 2

timeoutSeconds: 1

- name: xtrabackup

image: twoeo/gcr.io-google-samples-xtrabackup:latest

imagePullPolicy: IfNotPresent

ports:

- name: xtrabackup

containerPort: 3307

command:

- bash

- "-c"

- |set -ex

cd /var/lib/mysql

# 确定binlog 克隆数据位置(如果binlog存在的话).

if [[ -f xtrabackup_slave_info ]]; then

# 如果存在该文件，则该xrabackup是从现有的从节点克隆出来的。

mv xtrabackup_slave_info change_master_to.sql.in

# 在这种情况下，忽略xtrabackup_binlog_info(它是无用的)。

rm -f xtrabackup_binlog_info

elif [[ -f xtrabackup_binlog_info ]]; then

# 我们直接从主人那里克隆。分析binlog位置。

[[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1

rm xtrabackup_binlog_info

echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',

MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in

fi

# 检查是否需要通过启动复制来完成克隆.

if [[ -f change_master_to.sql.in ]]; then

echo "Waiting for mysqld to be ready (accepting connections)"

until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done

echo "Initializing replication from clone position"

# 如果容器重新启动，最多尝试一次。

mv change_master_to.sql.in change_master_to.sql.orig

mysql -h 127.0.0.1

- name: data

mountPath: /var/lib/mysql

subPath: mysql

- name: conf

mountPath: /etc/mysql/conf.d

resources:

requests:

cpu: 10m

memory: 10Mi

volumes:

- name: conf

emptyDir: {}

- name: config-map

configMap:

name: mysql

volumeClaimTemplates:

- metadata:

name: data

spec:

accessModes: ["ReadWriteOnce"]

resources:

requests:

storage: 0.1Gi