image.png
1. namespace
namespace随意，此处我将mysql集群部署在一个名为mysql的namespace下。namespace.yaml
#
apiVersion: v1
kind: Namespace
metadata:
name: mysql
labels:
app: mysql
2. configmap
在configmap里设置 MySQL 主服务器和从服务器的配置。configmap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: mysql
namespace: mysql
labels:
app: mysql
data:
master.cnf: |
# Apply this config only on the master.
[mysqld]
log-bin
slave.cnf: |
# Apply this config only on slaves.
[mysqld]
super-read-only
3. secret
将密码存入secret里，此处使用的是base64加密，可通过echo -n "PASSWORD" | base64来得到PASSWORD的base64值，此处以密码123456为例。secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: mysql-secret
namespace: mysql
labels:
app: mysql
type: Opaque
data:
password: MTIzNDU2 # echo -n "123456" | base64
4. services
Headless Service 给 StatefulSet 控制器为集合中每个 Pod 创建的 DNS 条目提供了一个宿主。因为 Headless Service 名为 mysql，所以可以通过在同一 Kubernetes 集群和 namespace 中的任何其他 Pod 内解析 <pod-name>.mysql 来访问 Pod。<br />客户端 Service 称为 mysql-read，是一种常规 Service，具有其自己的群集 IP，该群集 IP 在报告为就绪的所有MySQL Pod 中分配连接。可能端点的集合包括 MySQL 主节点和所有从节点。<br />请注意，只有读取查询才能使用负载平衡的客户端 Service。因为只有一个 MySQL 主服务器，所以客户端应直接连接到 MySQL 主服务器 Pod (通过其在 Headless Service 中的 DNS 条目)以执行写入操作。services.yaml
apiVersion: v1
kind: Service
metadata:
name: mysql
namespace: mysql
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
clusterIP: None
selector:
app: mysql
---
apiVersion: v1
kind: Service
metadata:
name: mysql-read
namespace: mysql
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
selector:
app: mysql
5. Statefulset
Statefulset.yaml
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: mysql
namespace: mysql
spec:
selector:
matchLabels:
app: mysql
serviceName: mysql
replicas: 3
template:
metadata:
labels:
app: mysql
spec:
initContainers:
- name: init-mysql
image: mysql:5.7
env:
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-secret
key: password
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 [[ $ordinal -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
volumeMounts:
- name: conf
mountPath: /mnt/conf.d
- name: config-map
mountPath: /mnt/config-map
- name: clone-mysql
image: gcr.io/google-samples/xtrabackup:1.0
env:
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-secret
key: password
command:
- bash
- "-c"
- |
set -ex
# Skip the clone if data already exists.
[[ -d /var/lib/mysql/mysql ]] && exit 0
# Skip the clone on master (ordinal index 0).
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1
ordinal=${BASH_REMATCH[1]}
[[ $ordinal -eq 0 ]] && exit 0
# Clone data from previous peer.
ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
# Prepare the backup.
xtrabackup --prepare --target-dir=/var/lib/mysql
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
containers:
- name: mysql
image: mysql:5.7
# env:
# - name: MYSQL_ALLOW_EMPTY_PASSWORD
# value: "1"
env:
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-secret
key: password
ports:
- name: mysql
containerPort: 3306
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 500m
memory: 1Gi
livenessProbe:
exec:
command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
# 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"]
command: ["mysqladmin", "ping", "-uroot", "-p${MYSQL_ROOT_PASSWORD}"]
initialDelaySeconds: 120
periodSeconds: 2
timeoutSeconds: 1
- name: xtrabackup
image: gcr.io/google-samples/xtrabackup:1.0
ports:
- name: xtrabackup
containerPort: 3307
env:
- name: MYSQL_ROOT_PASSWORD
valueFrom:
secretKeyRef:
name: mysql-secret
key: password
command:
- bash
- "-c"
- |
set -ex
cd /var/lib/mysql
# Determine binlog position of cloned data, if any.
if [[ -f xtrabackup_slave_info && "x$(<xtrabackup_slave_info)" != "x" ]]; then
# XtraBackup already generated a partial "CHANGE MASTER TO" query
# because we're cloning from an existing slave. (Need to remove the tailing semicolon!)
cat xtrabackup_slave_info | sed -E 's/;$//g' > change_master_to.sql.in
# Ignore xtrabackup_binlog_info in this case (it's useless).
rm -f xtrabackup_slave_info xtrabackup_binlog_info
elif [[ -f xtrabackup_binlog_info ]]; then
# We're cloning directly from master. Parse binlog position.
[[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || 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 -uroot -p${MYSQL_ROOT_PASSWORD} -e "SELECT 1"; do sleep 1; done
# until mysql -h 127.0.0.1 -e "SELECT 1"; do sleep 1; done
echo "Initializing replication from clone position"
mysql -h 127.0.0.1 -uroot -p${MYSQL_ROOT_PASSWORD} \
-e "$(<change_master_to.sql.in), \
MASTER_HOST='mysql-0.mysql.mysql', \
MASTER_USER='root', \
MASTER_PASSWORD='${MYSQL_ROOT_PASSWORD}', \
MASTER_CONNECT_RETRY=10; \
START SLAVE;" || exit 1
# In case of container restart, attempt this at-most-once.
mv change_master_to.sql.in change_master_to.sql.orig
fi
# Start a server to send backups when requested by peers.
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 --password=${MYSQL_ROOT_PASSWORD}"
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 100m
memory: 100Mi
volumes:
- name: conf
emptyDir: {}
- name: config-map
configMap:
name: mysql
volumeClaimTemplates:
- metadata:
name: data
namespace: mysql
annotations:
volume.beta.kubernetes.io/storage-class: "nfs"
spec:
accessModes: ["ReadWriteOnce"]
storageClassName: "nfs"
resources:
requests:
storage: 10Gi
volumeClaimTemplates我使用的nfs的存储，可换成其他任意存储。关于nfs-external-storage可参考我的文章：https://www.jianshu.com/p/1b9dbdc3d451。
6. 验证
6.1 show mysql-read server_id
kubectl exec -it mysql-0 -c mysql -n mysql /bin/bash #进入mysql的容器
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'SELECT @@server_id,NOW()'
mysql: [Warning] Using a password on the command line interface can be insecure.
+-------------+---------------------+
| @@server_id | NOW() |
+-------------+---------------------+
| 101 | 2020-08-11 08:07:09 |
+-------------+---------------------+
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'SELECT @@server_id,NOW()'
mysql: [Warning] Using a password on the command line interface can be insecure.
+-------------+---------------------+
| @@server_id | NOW() |
+-------------+---------------------+
| 100 | 2020-08-11 08:07:10 |
+-------------+---------------------+
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'SELECT @@server_id,NOW()'
mysql: [Warning] Using a password on the command line interface can be insecure.
6.2 show slave status
kubectl -n mysql exec mysql-1 -c mysql -- bash -c "mysql -uroot -p123456 -e 'show slave status \G'"
mysql: [Warning] Using a password on the command line interface can be insecure.
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: mysql-0.mysql.mysql
Master_User: root
Master_Port: 3306
Connect_Retry: 10
Master_Log_File: mysql-0-bin.000003
Read_Master_Log_Pos: 463
Relay_Log_File: mysql-1-relay-bin.000002
Relay_Log_Pos: 631
Relay_Master_Log_File: mysql-0-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 463
Relay_Log_Space: 840
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 100
Master_UUID: c8441cf0-daf3-11ea-bc2b-125ce95eb5da
Master_Info_File: /var/lib/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
6.3 test
在mysql创建一个test数据库，并在mysql-read中查看。
root@mysql-0:/# mysql -h mysql-0.mysql -uroot -p123456 -e 'create database test'
mysql: [Warning] Using a password on the command line interface can be insecure.
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'show databases'
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| xtrabackup_backupfiles |
+------------------------+
root@mysql-0:/# mysql -h mysql-0.mysql -uroot -p123456 -e 'show databases'
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| xtrabackup_backupfiles |
+------------------------+
root@mysql-0:/# mysql -h mysql-1.mysql -uroot -p123456 -e 'show databases'
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| xtrabackup_backupfiles |
+------------------------+
root@mysql-0:/# mysql -h mysql-2.mysql -uroot -p123456 -e 'show databases'
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| xtrabackup_backupfiles |
+------------------------+
在mysql-read端不能删除test数据库
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'drop database test'
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1290 (HY000) at line 1: The MySQL server is running with the --super-read-only option so it cannot execute this statement
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'show databases'
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| test |
| xtrabackup_backupfiles |
+------------------------+
在mysql端删除数据库成功
root@mysql-0:/# mysql -h mysql -uroot -p123456 -e 'drop database test'
mysql: [Warning] Using a password on the command line interface can be insecure.
root@mysql-0:/# mysql -h mysql-read -uroot -p123456 -e 'show databases'
mysql: [Warning] Using a password on the command line interface can be insecure.
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| xtrabackup_backupfiles |
+------------------------+
7. 参考
https://kubernetes.io/zh/docs/tasks/run-application/run-replicated-stateful-application/
https://lihaoquan.me/2020/3/6/mysql-master-slave-statefulset.html
网友评论