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本文来自 Apache Seata官方文档,欢迎访问官网,查看更多深度文章。
Apache Seata 高可用部署实践
Seata 高可用部署实践
使用配置中心和数据库来实现 Seata 的高可用,以 Nacos 和 MySQL 为例,将cloud-seata-nacos应用部署到 Kubernetes 集群中
该应用使用 Nacos 作为配置和注册中心,总共有三个服务: order-service, pay-service, storage-service, 其中 order-service 对外提供下单接口,当余额和库存充足时,下单成功,会提交事务,当不足时会抛出异常,下单失败,回滚事务
准备工作
需要准备可用的注册中心、配置中心 Nacos 和 MySQL,通常情况下,注册中心、配置中心和数据库都是已有的,不需要特别配置,在这个实践中,为了简单,只部署单机的注册中心、配置中心和数据库,假设他们是可靠的
- 部署 Nacos
在服务器部署 Nacos,开放 8848 端口,用于 seata-server 注册,服务器地址为 192.168.199.2
docker run --name nacos -p 8848:8848 -e MODE=standalone nacos/nacos-server
- 部署 MySQL
部署一台MySQL 数据库,用于保存事务数据,服务器地址为 192.168.199.2
docker run --name mysql -p 30060:3306-e MYSQL_ROOT_PASSWORD=123456 -d mysql:5.7.17
部署 seata-server
- 创建seata-server需要的表
具体的 SQL 参考 script/server/db,这里使用的是 MySQL 的脚本,数据库名称为 seata
同时,也需要创建 undo_log 表, 可以参考 script/client/at/db/
- 修改seata-server配置
将以下配置添加到 Nacos 配置中心,具体添加方法可以参考 script/config-center
service.vgroupMapping.my_test_tx_group=default
store.mode=db
store.db.datasource=druid
store.db.dbType=mysql
store.db.driverClassName=com.mysql.jdbc.Driver
store.db.url=jdbc:mysql://192.168.199.2:30060/seata?useUnicode=true
store.db.user=root
store.db.password=123456
部署 seata-server 到 Kubernetes
- seata-server.yaml
需要将 ConfigMap 的注册中心和配置中心地址改成相应的地址
apiVersion: v1
kind: Service
metadata:
name: seata-ha-server
namespace: default
labels:
app.kubernetes.io/name: seata-ha-server
spec:
type: ClusterIP
ports:
- port: 8091
protocol: TCP
name: http
selector:
app.kubernetes.io/name: seata-ha-server
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
name: seata-ha-server
namespace: default
labels:
app.kubernetes.io/name: seata-ha-server
spec:
serviceName: seata-ha-server
replicas: 3
selector:
matchLabels:
app.kubernetes.io/name: seata-ha-server
template:
metadata:
labels:
app.kubernetes.io/name: seata-ha-server
spec:
containers:
- name: seata-ha-server
image: docker.io/seataio/seata-server:latest
imagePullPolicy: IfNotPresent
env:
- name: SEATA_CONFIG_NAME
value: file:/root/seata-config/registry
ports:
- name: http
containerPort: 8091
protocol: TCP
volumeMounts:
- name: seata-config
mountPath: /root/seata-config
volumes:
- name: seata-config
configMap:
name: seata-ha-server-config
---
apiVersion: v1
kind: ConfigMap
metadata:
name: seata-ha-server-config
data:
registry.conf: |
registry {
type = "nacos"
nacos {
application = "seata-server"
serverAddr = "192.168.199.2"
}
}
config {
type = "nacos"
nacos {
serverAddr = "192.168.199.2"
group = "SEATA_GROUP"
}
}
- 部署
kubectl apply -f seata-server.yaml
部署完成后,会有三个 pod
kubectl get pod | grep seata-ha-server
seata-ha-server-645844b8b6-9qh5j 1/1 Running 0 3m14s
seata-ha-server-645844b8b6-pzczs 1/1 Running 0 3m14s
seata-ha-server-645844b8b6-wkpw8 1/1 Running 0 3m14s
待启动完成后,可以在 Nacos 的服务列表中发现三个 seata-server 的实例,至此,已经完成 seata-server 的高可用部署
- 查看服务日志
kubelet logs -f seata-ha-server-645844b8b6-9qh5j
[0.012s][info ][gc] Using Serial
2020-04-15 00:55:09.880 INFO [main]io.seata.server.ParameterParser.init:90 -The server is running in container.
2020-04-15 00:55:10.013 INFO [main]io.seata.config.FileConfiguration.<init>:110 -The configuration file used is file:/root/seata-config/registry.conf
2020-04-15 00:55:12.426 INFO [main]com.alibaba.druid.pool.DruidDataSource.init:947 -{dataSource-1} inited
2020-04-15 00:55:13.127 INFO [main]io.seata.core.rpc.netty.RpcServerBootstrap.start:155 -Server started
其中{dataSource-1}
说明使用了数据库,并正常初始化完成
- 查看注册中心,此时seata-serve 这个服务会有三个实例
部署业务服务
- 创建业务表并初始化数据
具体的业务表可以参考 cloud-seata-nacos/README.md
- 添加 Nacos 配置
在 public 的命名空间下,分别创建 data-id 为 order-service.properties
, pay-service.properties
, storage-service.properties
的配置,内容相同,需要修改数据库的地址、用户名和密码
# MySQL
spring.datasource.url=jdbc:mysql://192.168.199.2:30060/seata?useUnicode=true&characterEncoding=utf8&allowMultiQueries=true&useSSL=false
spring.datasource.username=root
spring.datasource.password=123456
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# Seata
spring.cloud.alibaba.seata.tx-service-group=my_test_tx_group
- 部署服务
通过 application.yaml 配置文件部署服务,需要注意的是修改 ConfigMap 的 NACOS_ADDR
为自己的 Nacos 地址
apiVersion: v1
kind: Service
metadata:
namespace: default
name: seata-ha-service
labels:
app.kubernetes.io/name: seata-ha-service
spec:
type: NodePort
ports:
- port: 8081
nodePort: 30081
protocol: TCP
name: http
selector:
app.kubernetes.io/name: seata-ha-service
---
apiVersion: v1
kind: ConfigMap
metadata:
name: seata-ha-service-config
data:
NACOS_ADDR: 192.168.199.2:8848
---
apiVersion: v1
kind: ServiceAccount
metadata:
name: seata-ha-account
namespace: default
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: seata-ha-account
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
name: seata-ha-account
namespace: default
---
apiVersion: apps/v1
kind: Deployment
metadata:
namespace: default
name: seata-ha-service
labels:
app.kubernetes.io/name: seata-ha-service
spec:
replicas: 1
selector:
matchLabels:
app.kubernetes.io/name: seata-ha-service
template:
metadata:
labels:
app.kubernetes.io/name: seata-ha-service
spec:
serviceAccountName: seata-ha-account
containers:
- name: seata-ha-order-service
image: "registry.cn-qingdao.aliyuncs.com/hellowoodes/seata-ha-order-service:1.1"
imagePullPolicy: IfNotPresent
env:
- name: NACOS_ADDR
valueFrom:
configMapKeyRef:
key: NACOS_ADDR
name: seata-ha-service-config
ports:
- name: http
containerPort: 8081
protocol: TCP
- name: seata-ha-pay-service
image: "registry.cn-qingdao.aliyuncs.com/hellowoodes/seata-ha-pay-service:1.1"
imagePullPolicy: IfNotPresent
env:
- name: NACOS_ADDR
valueFrom:
configMapKeyRef:
key: NACOS_ADDR
name: seata-ha-service-config
ports:
- name: http
containerPort: 8082
protocol: TCP
- name: seata-ha-storage-service
image: "registry.cn-qingdao.aliyuncs.com/hellowoodes/seata-ha-storage-service:1.1"
imagePullPolicy: IfNotPresent
env:
- name: NACOS_ADDR
valueFrom:
configMapKeyRef:
key: NACOS_ADDR
name: seata-ha-service-config
ports:
- name: http
containerPort: 8083
protocol: TCP
通过以下命令,将应用部署到集群中
kubectl apply -f application.yaml
然后查看创建的 pod,seata-ha-service 这个服务下有三个 pod
kubectl get pod | grep seata-ha-service
seata-ha-service-7dbdc6894b-5r8q4 3/3 Running 0 12m
待应用启动后,在 Nacos 的服务列表中,会有相应的服务
此时查看服务的日志,会看到服务向每一个 TC 都注册了
kubectl logs -f seata-ha-service-7dbdc6894b-5r8q4 seata-ha-order-service
查看任意的 TC 日志,会发现每一个服务都向 TC 注册了
kubelet logs -f seata-ha-server-645844b8b6-9qh5j
测试
测试成功场景
调用下单接口,将 price 设置为 1,因为初始化的余额为 10,可以下单成功
curl -X POST \
http://192.168.199.2:30081/order/placeOrder \
-H 'Content-Type: application/json' \
-d '{
"userId": 1,
"productId": 1,
"price": 1
}'
此时返回结果为:
{"success":true,"message":null,"data":null}
查看TC 的日志,事务成功提交:
查看 order-service 服务日志
测试失败场景
设置 price 为 100,此时余额不足,会下单失败抛出异常,事务会回滚
curl -X POST \
http://192.168.199.2:30081/order/placeOrder \
-H 'Content-Type: application/json' \
-d '{
"userId": 1,
"productId": 1,
"price": 100
}'
查看 TC 的日志:
查看服务的日志 :
多次调用查看服务日志,发现会随机的向其中某台TC发起事务注册,当扩容或缩容后,有相应的 TC 参与或退出,证明高可用部署生效