configMap.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: 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
headless-svc.yaml
apiVersion: v1
kind: Service
metadata:
name: mysql
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
clusterIP: None
selector:
app: mysql
statefulSet.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
imagePullPolicy: IfNotPresent
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 [[ $ordinal -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
volumeMounts:
- name: conf
mountPath: /mnt/conf.d
- name: config-map
mountPath: /mnt/config-map
- name: clone-mysql
image: twoeo/gcr.io-google-samples-xtrabackup:latest
imagePullPolicy: IfNotPresent
command:
- bash
- "-c"
- |
set -ex
# Skip the clone if data already exists.
[[ -d /var/lib/mysql/mysql ]] && exit 0
# Skip the clone on master (ordinal index 0).
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1
ordinal=${BASH_REMATCH[1]}
[[ $ordinal -eq 0 ]] && exit 0
# Clone data from previous peer.
ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
# Prepare the backup.
xtrabackup --prepare --target-dir=/var/lib/mysql
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
containers:
- name: mysql
image: mysql:5.7
imagePullPolicy: IfNotPresent
env:
- name: MYSQL_ALLOW_EMPTY_PASSWORD
value: "1"
ports:
- name: mysql
containerPort: 3306
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 50m
memory: 50Mi
livenessProbe:
exec:
command: ["mysqladmin", "ping"]
initialDelaySeconds: 30
periodSeconds: 10
timeoutSeconds: 5
readinessProbe:
exec:
# Check we can execute queries over TCP (skip-networking is off).
command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
initialDelaySeconds: 5
periodSeconds: 2
timeoutSeconds: 1
- name: xtrabackup
image: twoeo/gcr.io-google-samples-xtrabackup:latest
imagePullPolicy: IfNotPresent
ports:
- name: xtrabackup
containerPort: 3307
command:
- bash
- "-c"
- |
set -ex
cd /var/lib/mysql
# Determine binlog position of cloned data, if any.
if [[ -f xtrabackup_slave_info ]]; then
# XtraBackup already generated a partial "CHANGE MASTER TO" query
# because we're cloning from an existing slave.
mv xtrabackup_slave_info change_master_to.sql.in
# Ignore xtrabackup_binlog_info in this case (it's useless).
rm -f xtrabackup_binlog_info
elif [[ -f xtrabackup_binlog_info ]]; then
# We're cloning directly from master. Parse binlog position.
[[ `cat xtrabackup_binlog_info` =~ ^(.*?)[[:space:]]+(.*?)$ ]] || exit 1
rm 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
# 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"
# In case of container restart, attempt this at-most-once.
mv change_master_to.sql.in change_master_to.sql.orig
mysql -h 127.0.0.1 <<EOF
$(<change_master_to.sql.orig),
MASTER_HOST='mysql-0.mysql',
MASTER_USER='root',
MASTER_PASSWORD='',
MASTER_CONNECT_RETRY=10;
START SLAVE;
EOF
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"
volumeMounts:
- 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
annotations:
volume.beta.kubernetes.io/storage-class: "managed-nfs-storage"
spec:
accessModes: ["ReadWriteOnce"]
resources:
requests:
storage: 0.1Gi
查看
[root@K8S-M1 xtrabackup]# kubectl get all | grep mysql
pod/mysql-0 2/2 Running 5 10h
pod/mysql-1 2/2 Running 3 10h
pod/mysql-2 2/2 Running 5 9h
service/mysql ClusterIP None <none> 3306/TCP 6h31m
statefulset.apps/mysql 3 3 10h
测试
(master: mysql-0)
[root@K8S-M1 xtrabackup]# kubectl exec -it mysql-0 bash
root@mysql-0:/# mysql
mysql> show databases;
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| xtrabackup_backupfiles |
+------------------------+
5 rows in set (0.12 sec)
(salve:mysql-1)
[root@K8S-M1 xtrabackup]# kubectl exec -it mysql-1 bash
root@mysql-0:/# mysql
mysql> show databases;
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| xtrabackup_backupfiles |
+------------------------+
5 rows in set (0.12 sec)
(salve:mysql-2)
[root@K8S-M1 xtrabackup]# kubectl exec -it mysql-2 bash
root@mysql-0:/# mysql
mysql> show databases;
+------------------------+
| Database |
+------------------------+
| information_schema |
| mysql |
| performance_schema |
| sys |
| xtrabackup_backupfiles |
+------------------------+
5 rows in set (0.12 sec)
只有master(mysql-0)才有一切操作（读写删....）权限，而salve（mysql-1,mysql-2）只有读的权限
在salve(mysql-1或mysql-2)上操作
mysql> CREATE DATABASE demo;
ERROR 1290 (HY000): The MySQL server is running with the --super-read-only option so it cannot execute this statement
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
同步操作测试
在master(mysql-0)上操作(创建database,表，插值)
mysql> CREATE DATABASE demo;
Query OK, 1 row affected (0.04 sec)
mysql> CREATE TABLE demo.messages (message VARCHAR(250));
Query OK, 0 rows affected (0.05 sec)
mysql> INSERT INTO demo.messages VALUES ('hello');
Query OK, 1 row affected (0.01 sec)
在salve(mysql-1,mysql-2上操作)
mysql> show databases;
+------------------------+
| Database |
+------------------------+
| information_schema |
| demo |
| mysql |
| performance_schema |
| sys |
| xtrabackup_backupfiles |
+------------------------+
6 rows in set (0.15 sec)
mysql> use demo;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
Database changed
mysql> select * from messages;
+---------+
| message |
+---------+
| hello |
+---------+
1 row in set (0.00 sec)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
ok,可以发现同步实现成功。
再创建一个svc来提供对外服务
svc.yaml
# Client service for connecting to any MySQL instance for reads.
# For writes, you must instead connect to the master: mysql-0.mysql.
apiVersion: v1
kind: Service
metadata:
name: mysql-read
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
selector:
app: mysql
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