k8s搭建mysql集群實現主從復制的方法步驟
環境介紹
| 名稱 | 版本 | 操作系統 | IP | 備註 |
|---|---|---|---|---|
| K8S集群 | 1.20.15 | Centos7.9 | 192.168.11.21 192.168.11.22 192.168.11.23 | 21為k8s-master 22為k8s-node01 23為k8s-node02 |
| MySql | 5.7 | Centos7.9 | 一主兩從 | |
| nfs服務器 | Centos7.9 | 192.168.11.24 | 共享目錄為/nfs |
一、部署NFS服務器
11.24：
1.創建NFS共享目錄
mkdir -p /nfs
2.安裝NFS服務
yum -y install nfs-utils rpcbind
3.編輯NFS配置
echo "/nfs *(rw,async,no_root_squash)" >>/etc/exports
4.啟動服務
systemctl enable --now nfs-server systemctl enable --now rpcbind
5.驗證
showmount -e ##看是否能看到/nfs *字段；如果沒有該命令yum -y install showmount
11.21/22/23（所有K8S節點）：
1.安裝NFS
yum -y install nfs-utils
2.測試是否能檢測到NFS共享目錄
showmount -e 192.168.11.24 ##看是否能看到/nfs *
二、創建PV
11.21：
1、創建存放MySQL的yaml清單目錄
mkdir -p /webapp cd /webapp
2、創建NFS的YAML文件
vim nfs-client.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nfs-client-provisioner
labels:
app: nfs-client-provisioner
# replace with namespace where provisioner is deployed
namespace: default
spec:
replicas: 1
strategy:
type: Recreate
selector:
matchLabels:
app: nfs-client-provisioner
template:
metadata:
labels:
app: nfs-client-provisioner
spec:
serviceAccountName: nfs-client-provisioner
containers:
- name: nfs-client-provisioner
image: registry.cn-beijing.aliyuncs.com/xngczl/nfs-subdir-external-provisione:v4.0.0
volumeMounts:
- name: nfs-client-root
mountPath: /persistentvolumes
env:
- name: PROVISIONER_NAME
value: fuseim.pri/ifs #註意這個值，可以自定義
- name: NFS_SERVER
value: 192.168.11.24 ##IP不同修改此處
- name: NFS_PATH
value: /nfs ##nfs共享目錄
volumes:
- name: nfs-client-root
nfs:
server: 192.168.11.24 ##IP不同修改此處
path: /nfs ##nfs共享目錄
創建rbac
vim nfs-client-rbac.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
name: nfs-client-provisioner
# replace with namespace where provisioner is deployed
namespace: default
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: nfs-client-provisioner-runner
rules:
- apiGroups: [""]
resources: ["nodes"]
verbs: ["get", "list", "watch"]
- apiGroups: [""]
resources: ["persistentvolumes"]
verbs: ["get", "list", "watch", "create", "delete"]
- apiGroups: [""]
resources: ["persistentvolumeclaims"]
verbs: ["get", "list", "watch", "update"]
- apiGroups: ["storage.k8s.io"]
resources: ["storageclasses"]
verbs: ["get", "list", "watch"]
- apiGroups: [""]
resources: ["events"]
verbs: ["create", "update", "patch"]
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: run-nfs-client-provisioner
subjects:
- kind: ServiceAccount
name: nfs-client-provisioner
# replace with namespace where provisioner is deployed
namespace: default
roleRef:
kind: ClusterRole
name: nfs-client-provisioner-runner
apiGroup: rbac.authorization.k8s.io
---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: leader-locking-nfs-client-provisioner
# replace with namespace where provisioner is deployed
namespace: default
rules:
- apiGroups: [""]
resources: ["endpoints"]
verbs: ["get", "list", "watch", "create", "update", "patch"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: leader-locking-nfs-client-provisioner
# replace with namespace where provisioner is deployed
namespace: default
subjects:
- kind: ServiceAccount
name: nfs-client-provisioner
# replace with namespace where provisioner is deployed
namespace: default
roleRef:
kind: Role
name: leader-locking-nfs-client-provisioner
apiGroup: rbac.authorization.k8s.io
創建sc
vim nfs-client-class.yaml
apiVersion: storage.k8s.io/v1 kind: StorageClass metadata: name: course-nfs-storage
啟動：
kubectl apply -f nfs-client.yaml kubectl apply -f nfs-client-rbac.yaml kubectl apply -f nfs-client-class.yaml kubectl get po,sc NAME READY STATUS RESTARTS AGE pod/nfs-client-provisioner-8579c9d69b-m6vp4 1/1 Running 0 13m NAME PROVISIONER RECLAIMPOLICY VOLUMEBINDINGMODE ALLOWVOLUMEEXPANSION AGE storageclass.storage.k8s.io/course-nfs-storage fuseim.pri/ifs Delete Immediate false 13m
三、編寫MySQL的yaml文件
11.21：
mkdir -p /weapp/mysql cd /weapp/mysql
創建CM
“`bash
vim mysql-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
此文件定義瞭兩個MySQL的配置文件
1.是master.cnf，開啟瞭log-bin。開啟二進制日志文件後才能進行主從復制
2.slave.cnf，開啟瞭super-read-only，表示從節點隻能讀，不能進行其他操作。
兩個文件以配置文件形式掛載到mysql容器中`
創建MySQL的Service
vim mysql-services.yaml
apiVersion: v1
kind: Service
metadata:
name: 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
labels:
app: mysql
spec:
ports:
- name: mysql
port: 3306
selector:
app: mysql
創MySQL的StatefulSet
vim 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
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 [[ $ordinal -eq 0 ]]; then
cp /mnt/config-map/master.cnf /mnt/conf.d/
else
cp /mnt/config-map/slave.cnf /mnt/conf.d/
fi
volumeMounts:
- name: conf
mountPath: /mnt/conf.d
- name: config-map
mountPath: /mnt/config-map
- name: clone-mysql
image: fxkjnj/xtrabackup:1.0
command:
- bash
- "-c"
- |
set -ex
# Skip the clone if data already exists.
[[ -d /var/lib/mysql/mysql ]] && exit 0
# Skip the clone on master (ordinal index 0).
[[ `hostname` =~ -([0-9]+)$ ]] || exit 1
ordinal=${BASH_REMATCH[1]}
[[ $ordinal -eq 0 ]] && exit 0
# Clone data from previous peer.
ncat --recv-only mysql-$(($ordinal-1)).mysql 3307 | xbstream -x -C /var/lib/mysql
# Prepare the backup.
xtrabackup --prepare --target-dir=/var/lib/mysql
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
containers:
- name: mysql
image: mysql:5.7
env:
- name: MYSQL_ALLOW_EMPTY_PASSWORD
value: "1"
ports:
- name: mysql
containerPort: 3306
volumeMounts:
- name: data
mountPath: /var/lib/mysql
subPath: mysql
- name: conf
mountPath: /etc/mysql/conf.d
resources:
requests:
cpu: 500m
memory: 1Gi
livenessProbe:
exec:
command: ["mysqladmin", "ping"]
initialDelaySeconds: 30
periodSeconds: 10
timeoutSeconds: 5
readinessProbe:
exec:
# Check we can execute queries over TCP (skip-networking is off).
command: ["mysql", "-h", "127.0.0.1", "-e", "SELECT 1"]
initialDelaySeconds: 5
periodSeconds: 2
timeoutSeconds: 1
- name: xtrabackup
image: fxkjnj/xtrabackup:1.0
ports:
- name: xtrabackup
containerPort: 3307
command:
- bash
- "-c"
- |
set -ex
cd /var/lib/mysql
# Determine binlog position of cloned data, if any.
if [[ -f xtrabackup_slave_info && "x$(<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:
storageClassName: "course-nfs-storage"
accessModes: ["ReadWriteOnce"]
resources:
requests:
storage: 0.5Gi
- 使用xtrbackup工具進行初始化數據的備份
- 使用linux自帶的ncat工具進行容器初始化數據拷貝
- 使用mysql的bin-log實現主從復制
- 使用mysqladmin的ping作為健康檢查方式
- 利用pod的主機名的序號來判定當前節點為主還是從，再根據節點拷貝不同的配置文件到指定目錄
四、啟動MySQL
11.21
kubectl apply -f mysql-configmap.yaml kubectl apply -f mysql-services.yaml kubectl apply -f mysql-statefulset.yaml kubectl get po NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES mysql-0 2/2 Running 0 3h12m 10.244.0.5 k8s-master1 <none> <none> mysql-1 2/2 Running 0 3h11m 10.244.1.6 k8s-node02 <none> <none> mysql-2 2/2 Running 0 3h10m 10.244.1.5 k8s-node01 <none> <none>
五、驗證MySQL主從復制
11.21：
kubectl exec -it mysql-0 -- bash ##進入mysqk-0pod
mysql -h mysql-0.mysql ##進入數據庫
CREATE DATABASE test; ##創建庫表。
CREATE TABLE test.messages (message VARCHAR(250));
INSERT INTO test.messages VALUES ('hello');
\q
exit
kubectl exec -it mysql-1 -- bash ##進入mysql-1pod
mysql -h mysql-1.mysql ##進入數據庫
SELECT * FROM test.messages; ##看是否看得到創建的test庫
獲得以下輸出
Waiting for pod default/mysql-client to be running, status is Pending, pod ready: false
+———+
| message |
+———+
| hello |
+———+
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