MySQL集群：关于k8s环境部署mysql主从的问题

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

# Headless service for stable DNS entries of StatefulSet members.
apiVersion: v1
kind: Service
metadata:
name: mysql
namespace: mysql
labels:
app: mysql
spec:
ports:
– name: mysql
port: 3306
clusterIP: None
selector:
app: mysql
—
# 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
namespace: mysql
labels:
app: mysql
spec:
ports:
– name: mysql
port: 3306
selector:
app: mysql

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:
tolerations:
– effect: NoSchedule
operator: Exists
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms: # 调度指定标签节点
– matchExpressions:
– key: node-role.kubernetes.io/compute
operator: In
values:
– dedicated-middleware
initContainers:
– name: init-mysql
image: mysql:5.7.35
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 [[ $ordinal -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
volumeMounts:
– name: conf
mountPath: /mnt/conf.d
– name: config-map
mountPath: /mnt/config-map
– name: clone-mysql
image: registry.cn-shanghai.aliyuncs.com/soulchild/xtrabackup:2.4
command:
– bash
– “-c”
– |
set -ex
# Skip the clone if data already exists.
[[ -d /var/lib/mysql/mysql ]] && exit 0
# Skip the clone on master (ordinal index 0).
[[ `hostname` =~ -([0-9]+)$ ]] || 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:5.7.35
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: registry.cn-shanghai.aliyuncs.com/soulchild/xtrabackup:2.4
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$(<xtrabackup_slave_info)” != “x” ]]; then
# XtraBackup already generated a partial “CHANGE MASTER TO” query
# because we’re cloning from an existing slave. (Need to remove the tailing semicolon!)
cat xtrabackup_slave_info | sed -E ‘s/;$//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 -e “SELECT 1”; do sleep 1; done

echo “Initializing replication from clone position”
mysql -h 127.0.0.1 \
-e “$(<change_master_to.sql.in), \
MASTER_HOST=’mysql-0.mysql’, \
MASTER_USER=’root’, \
MASTER_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”
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
spec:
accessModes:
– ReadWriteOnce
resources:
requests:
storage: 30Gi