k8s（七）—statefullset部署mysql主从集群
1 使用statefullset部署mysql主从集群
mysql-0是master
mysql-1和mysql-2是两个备份
当mysql写的时候，找headless service中的mysql-0.mysql；当mysql读的时候，找clusterip service中的mysql读，实现读写分离。
statefulset维护三个副本，一个主两个从
因为主从的配置不同所以通过configmap来解决主从配置不同的问题
部署mysql文档
1.1配置configmap(创建mysql配置）
[root@server2 statefulset]# mkdir mysql
[root@server2 statefulset]# cd mysql/
[root@server2 mysql]# \vi cm.yaml 将官网的例子复制过来
apiVersion: v1
kind: ConfigMap
metadata:
name: mysql
labels:
app: mysql
data:
master.cnf: |
[mysqld]
log-bin # 主mysql激活二进制日志
slave.cnf: |
[mysqld]
super-read-only # 从mysql上面设置为只读
[root@server2 mysql]# kubectl apply -f cm.yaml 运行
configmap/mysql created
[root@server2 mysql]# kubectl get cm
NAME DATA AGE
kube-root-ca.crt 1 7h40m
mysql 2 13m
1.2创建service服务
[root@server2 mysql]# \vi svc.yaml 将官网的例子复制过来，然后用vim打开
[root@server2 mysql]# vim svc.yaml 创建两个svc，主要用于读写分离
apiVersion: v1
kind: Service
metadata:
name: mysql
labels:
app: mysql
spec:
ports:
- name: mysql 负责写
port: 3306
clusterIP: None
selector:
app: mysql
---
apiVersion: v1
kind: Service
metadata:
name: mysql-read 只读
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
selector:
app: mysql
[root@server2 mysql]# kubectl apply -f svc.yaml 创建
service/mysql created
service/mysql-read created
[root@server2 mysql]# kubectl get svc 查看svc，创建成功
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 443/TCP 7h39m
mysql ClusterIP None 3306/TCP 28s
mysql-read ClusterIP 10.101.37.222 3306/TCP 28s
1.3 statefulset配置
[root@server1 ~]# docker pull mysql:5.7 拉取mysql ，注意版本必须是5.7
[root@foundation50 k8s]# scp mysql-xtrabackup.tar server1:
[root@server1 ~]# docker load -i mysql-xtrabackup.tar 导入镜像
[root@server1 harbor]# docker push reg.westos.org/library/mysql:5.7 上传镜像到仓库
[root@server1 harbor]# docker push reg.westos.org/library/xtrabackup:1.0 上传镜像到仓库
[root@server2 mysql]# vim deploy.yaml
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
command:
- bash
- "-c"
- |
set -ex
# Generate mysql server-id from pod ordinal index.
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1 过滤第一个pod名mysql，其中hostname表示容器内pod名字
ordinal=${BASH_REMATCH[1]} 表示拿取第一个数字0
echo [mysqld] > /mnt/conf.d/server-id.cnf 创建一个server-id.cnf 文件，往里面写mysqld表示这个文件里的配置针对server生效
# Add an offset to avoid reserved server-id=0 value.
echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf 往server-id.conf 追加一条server-id=100+上面取到的数字
# Copy appropriate conf.d files from config-map to emptyDir. 拷贝conf.d 文件到空卷
if [[ $ordinal -eq 0 ]]; then 如果取到的数字为0
cp /mnt/config-map/master.cnf /mnt/conf.d/ 拷贝master
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/ 否则拷贝slave
fi
volumeMounts:
- name: conf
mountPath: /mnt/conf.d
- name: config-map
mountPath: /mnt/config-map
containers:
- name: mysql
image: mysql:5.7
env:
- name: MYSQL_ALLOW_EMPTY_PASSWORD
value: "1"
ports:
- name: mysql
containerPort: 3306
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql 挂在点里创建一个子目录
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 500m
memory: 1Gi
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
volumes:
- name: conf
emptyDir: {}
- name: config-map
configMap:
name: mysql
volumeClaimTemplates:
- metadata:
name: data
spec:
accessModes: ["ReadWriteOnce"]
resources:
requests:
storage: 10Gi
[root@server2 mysql]# kubectl apply -f deploy.yaml 创建
[root@server2 mysql]# kubectl get pod
NAME READY STATUS RESTARTS AGE
mysql-0 1/1 Running 0 71s
[root@server2 mysql]# kubectl get pv pv已经生成
NAME CAPACITY ACCESS MODES RECLAIM POLICY STATUS CLAIM STORAGECLASS REASON AGE
pvc-179b1b5e-3d25-4741-8458-a99b18f175de 1Gi RWX Delete Bound default/test-claim managed-nfs-storage 5h6m
pvc-4b2ad3b8-d156-429a-bc7a-f6616534e14f 10Gi RWO Delete Bound default/data-mysql-0 managed-nfs-storage 5h
[root@server2 mysql]# kubectl get pvc pvc已经生成
NAME STATUS VOLUME CAPACITY ACCESS MODES STORAGECLASS AGE
data-mysql-0 Bound pvc-4b2ad3b8-d156-429a-bc7a-f6616534e14f 10Gi RWO managed-nfs-storage 5h
test-claim Bound pvc-179b1b5e-3d25-4741-8458-a99b18f175de 1Gi RWX managed-nfs-storage 5h6m
[root@server1 ~]# cd /nfsdata/ 查看共享目录
[root@server1 nfsdata]# ls
default-data-mysql-0-pvc-4b2ad3b8-d156-429a-bc7a-f6616534e14f
[root@server1 nfsdata]# cd default-data-mysql-0-pvc-4b2ad3b8-d156-429a-bc7a-f6616534e14f/
[root@server1 default-data-mysql-0-pvc-4b2ad3b8-d156-429a-bc7a-f6616534e14f]# ls
mysql 创建的子目录
[root@server1 mysql]# ls
auto.cnf ibdata1 mysql-0-bin.000002 public_key.pem
ca-key.pem ib_logfile0 mysql-0-bin.000003 server-cert.pem
ca.pem ib_logfile1 mysql-0-bin.000004 server-key.pem
client-cert.pem ibtmp1 mysql-0-bin.index sys
client-key.pem mysql performance_schema
ib_buffer_pool mysql-0-bin.000001 private_key.pem
[root@server2 mysql]# kubectl logs mysql-0 -c init-mysql 查看初始化容器日志输出
++ hostname
+ [[ mysql-0 =~ -([0-9]+)$ ]]
+ ordinal=0
+ echo '[mysqld]'
+ echo server-id=100
+ [[ 0 -eq 0 ]]
+ cp /mnt/config-map/master.cnf /mnt/conf.d/
[root@server2 mysql]# kubectl exec mysql-0 -c mysql -- ls /etc/mysql/conf.d 查看容器挂载目录的内容，有两个文件
master.cnf
server-id.cnf
[root@server2 mysql]# kubectl exec mysql-0 -c mysql -- cat /etc/mysql/conf.d/master.cnf 查看文件具体内容
[mysqld]
log-bin
[root@server2 mysql]# kubectl exec mysql-0 -c mysql -- cat /etc/mysql/conf.d/server-id.cnf 查看文件具体内容
[mysqld]
server-id=100
上述master已经设置成功，该设置slave了
[root@server2 mysql]# kubectl apply -f deploy.yaml 创建，删除pod
statefulset.apps/mysql configured
[root@server2 mysql]# vim deploy.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: mysql
spec:
selector:
matchLabels:
app: mysql
serviceName: mysql
replicas: 1 1个副本数
template:
metadata:
labels:
app: mysql
spec:
initContainers:
- name: init-mysql
image: mysql:5.7
command:
- bash
- "-c"
- |
set -ex
# Generate mysql server-id from pod ordinal index.
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1
ordinal=${BASH_REMATCH[1]}
echo [mysqld] > /mnt/conf.d/server-id.cnf
# Add an offset to avoid reserved server-id=0 value.
echo server-id=$((100 + $ordinal)) >> /mnt/conf.d/server-id.cnf
# Copy appropriate conf.d files from config-map to emptyDir.
if [[ $ordinal -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
volumeMounts:
- name: conf
mountPath: /mnt/conf.d
- name: config-map
mountPath: /mnt/config-map
mountPath: /mnt/config-map
- name: clone-mysql 在科隆一个镜像xtrabackup，用于接收mysql-0的数据
image: xtrabackup:1.0
command:
- bash
- "-c"
- |
set -ex
# Skip the clone if data already exists.
[[ -d /var/lib/mysql/mysql ]] && exit 0
# Skip the clone on master (ordinal index 0).
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1
ordinal=${BASH_REMATCH[1]}
[[ $ordinal -eq 0 ]] && exit 0
# Clone data from previous peer.
ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql 接收数据
# Prepare the backup.
xtrabackup --prepare --target-dir=/var/lib/mysql
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
containers:
- name: mysql
image: mysql:5.7
env:
- name: MYSQL_ALLOW_EMPTY_PASSWORD
value: "1"
ports:
- name: mysql
containerPort: 3306
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 500m
memory: 1Gi
livenessProbe:
exec:
command: ["mysqladmin", "ping"]
initialDelaySeconds: 30
periodSeconds: 10
timeoutSeconds: 5
readinessProbe:
exec:
# Check we can execute queries over TCP (skip-networking is off).
command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
initialDelaySeconds: 5
periodSeconds: 2
timeoutSeconds: 1
- name: xtrabackup
image: xtrabackup:1.0
ports:
- name: xtrabackup
containerPort: 3307
command:
- bash
- "-c"
- |
set -ex
cd /var/lib/mysql
# Determine binlog position of cloned data, if any.
if [[ -f xtrabackup_slave_info && "x$( change_master_to.sql.in
# Ignore xtrabackup_binlog_info in this case (it's useless).
rm -f xtrabackup_slave_info xtrabackup_binlog_info
elif [[ -f xtrabackup_binlog_info ]]; then
# We're cloning directly from master. Parse binlog position.
[[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
rm -f xtrabackup_binlog_info xtrabackup_slave_info
echo "CHANGE MASTER TO MASTER_LOG_FILE='${BASH_REMATCH[1]}',\
MASTER_LOG_POS=${BASH_REMATCH[2]}" > change_master_to.sql.in
fi
# Check if we need to complete a clone by starting replication.
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"
mysql -h 127.0.0.1 \
-e "$( 
[root@server2 mysql]# kubectl logs mysql-1 -c init-mysql 查看初始化日志输出
++ hostname
+ [[ mysql-1 =~ -([0-9]+)$ ]]
+ ordinal=1 数字取1
+ echo '[mysqld]'
+ echo server-id=101 server-id 就是100+1
+ [[ 1 -eq 0 ]] id不等0则拷贝slave.cnf
+ cp /mnt/config-map/slave.cnf /mnt/conf.d/
[root@server2 mysql]# kubectl logs mysql-1 clone-mysql 查看clone日志输出
+ [[ -d /var/lib/mysql/mysql ]]
++ hostname
+ [[ mysql-1 =~ -([0-9]+)$ ]]
+ ordinal=1
+ [[ 1 -eq 0 ]]
+ ncat --recv-only mysql-0.mysql 3307 开启一个3307端口，接收mysql-0数据
+ xbstream -x -C /var/lib/mysql
+ xtrabackup --prepare --target-dir=/var/lib/mysql
查看克隆日志输出
[root@server2 mysql]# vim deploy.yaml
[root@server2 mysql]# kubectl apply -f deploy.yaml 创建
[root@server2 mysql]# kubectl get pod 创建成功
NAME READY STATUS RESTARTS AGE
mysql-0 2/2 Terminating 0 37m
mysql-1 2/2 Running 0 101s
mysql-2 2/2 Running 1 (22s ago) 89s
[root@server2 mysql]# kubectl logs mysql-2 clone-mysql
+ [[ -d /var/lib/mysql/mysql ]]
++ hostname
+ [[ mysql-2 =~ -([0-9]+)$ ]]
+ ordinal=2
+ [[ 2 -eq 0 ]]
+ ncat --recv-only mysql-1.mysql 3307 第2个slave是从第一个slave拿数据
+ xbstream -x -C /var/lib/mysql
+ xtrabackup --prepare --target-dir=/var/lib/mysql
[root@server2 mysql]# kubectl logs mysql-2 xtrabackup
+ cd /var/lib/mysql
+ [[ -f xtrabackup_slave_info ]] 直接获取上一个slave标志，这里面已经有之前的sql语句
+ [[ xCHANGE MASTER TO MASTER_LOG_FILE='mysql-0-bin.000005', MASTER_LOG_POS=154 != \x ]]
+ cat xtrabackup_slave_info
+ sed -E 's/;$//g'
+ rm -f xtrabackup_slave_info xtrabackup_binlog_info
+ [[ -f change_master_to.sql.in ]]
Initializing replication from clone position
+ mysql -h 127.0.0.1 -e 'CHANGE MASTER TO MASTER_LOG_FILE='\''mysql-0-bin.000005'\'', MASTER_LOG_POS=154, MASTER_HOST='\''mysql-0.mysql'\'', MASTER_USER='\''root'\'', MASTER_PASSWORD='\'''\'', MASTER_CONNECT_RETRY=10; START SLAVE;'
+ mv change_master_to.sql.in change_master_to.sql.orig
+ exec ncat --listen --keep-open --send-only --max-conns=1 3307 -c 'xtrabackup --backup --slave-info --stream=xbstream --host=127.0.0.1 --user=root'
测试：
