Table of contents
Distributed traffic protection_Sentinel console environment installation based on Linux
Distributed traffic protection_Sentinel console environment installation based on Docker
Distributed traffic protection_connecting applications to Sentinel
Distributed Traffic Protection_Traffic Control Overview
Distributed traffic protection_direct mode of flow control mode
Distributed traffic protection_Association mode of flow control mode
Distributed traffic protection_ link mode of flow control mode
Distributed traffic protection_Sentinel console environment installation based on Linux
Get Sentinel Console
Download https://github.com/alibaba/Sentinel/releases
Start Sentinel Console
linux mode
java -Dserver.port=8878 \
-
Dcsp.sentinel.dashboard.server=192.168.66.100:8878 \
-Dproject.name=sentinel-dashboard \
-jar ./sentinel-dashboard.jarRunning in background: nohup java -server -Xms64m -Xmx256m - Dserver.port=8878 - Dcsp.sentinel.dashboard.server=192.168.66.100:8878- Dproject.name=sentinel-dashboard -jar sentineldashboard-1.8.3.jar >> /opt/sentinel.log 2>& 1 &
windows mode
java -jar ./sentinel-dashboard.jar \
--server.port=8858 \
--
csp.sentinel.dashboard.server=192.168.66.101:8858 \
--project.name=sentinel-dashboardNote: It is strongly recommended to use JRE8 to start the Sentinel console. There may be unknown bugs in higher versions of JDK.
test access
访问http://192.168.66.101:8858 即可，登录用户名密码都是 sentinel。
Distributed traffic protection_Sentinel console environment installation based on Docker
pull image
docker pull docker.io/bladex/sentinel-dashboardCreate a boot container
docker run --name sentinel --restart=always -d -p 8888:8858 docker.io/bladex/sentinel-dashboard
view container
docker ps
test access
访问http://192.168.66.101:8858即可，登录用户名密码都是 sentinel。
Distributed traffic protection_connecting applications to Sentinel
Create project cloud-sentinel-payment8001
POM introduces dependencies
<dependencies>
<!-- Nacos 依赖-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloudstarter-alibaba-nacos-discovery</artifactId>
</dependency>
<!-- sentinel依赖-->
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloudstarter-alibaba-sentinel</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--借用监控开放端口-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
</dependencies>
Write the main startup class
@SpringBootApplication
@Slf4j
public class PaymentSentinelMain8001 {
public static void main(String[] args) {
SpringApplication.run(PaymentSentinelMain8001.class,args);
log.info("************PaymentSentinelMain8001 启动成功 **********");
}
}Write a YML configuration file
server:
port: 8001
spring:
application:
#应用名字
name: cloud-sentinel-payment
cloud:
nacos:
discovery:
# Nacos地址
server-addr: 192.168.66.101:8848
sentinel:
transport:
# Sentinel 控制台地址
dashboard: 192.168.66.101:8858
# sentinel api端⼝，默认8719
port: 8719Write a test controller
@RestController
public class FlowLimitController {
@GetMapping("testA")
public String testA(){
return "------------testA";
}
}View Sentinel control layer
send request
Send http://192.168.66.101:8858
Distributed Traffic Protection_Traffic Control Overview
Monitor the QPS or the number of concurrent threads of the application traffic, and control the traffic when the specified threshold is reached, so as to avoid being overwhelmed by the instantaneous traffic peak, thereby ensuring the high availability of the application.
Flow Control Design Concept
Flow control has the following angles:
Resource invocation relationship: such as resource invocation link, relationship between resources and resources;
Operating indicators: such as QPS, thread pool, system load, etc.;
The effect of control: such as direct current limiting, cold start, queuing, etc.
flow control rules
parameter:
1. Resource name
In fact, it is the resource path we requested
2. For the source
This is the flow control rule corresponding to those microservices for flow control management. Generally, fill in the name of the microservice of the caller, and use "," to separate multiple
3. Threshold type
Generally, there are 2 types, QPS (the maximum number of requests per second 2) and the number of threads (the number of concurrent threads)
4. Stand-alone threshold
The maximum limit value in stand-alone state
5. Whether to cluster
Choose according to the actual situation
flow control mode
Flow control effect
parameter:
1. Fail fast
The default flow control method, when the QPS exceeds the threshold of any rule, the new request will be rejected immediately, and the rejection method is to throw FlowException.
2、Warm Up
That is, warm-up/cold start mode. When the system has been at a low water level for a long time, when the flow rate suddenly increases, directly pulling the system to a high water level may overwhelm the system instantly. Through "cold start", let the passing flow increase slowly, gradually increase to the upper threshold within a certain period of time, give the cold system a warm-up time, and avoid the cold system from being pressurized.
3. Waiting in line
The uniform speed queuing method will strictly control the interval time for requests to pass through, that is, let the requests pass through at a uniform speed, corresponding to the leaky bucket algorithm. This method is mainly used to deal with intermittent burst traffic.
Real-time effect feedback
1. Sentienl's default flow control mode is _____.
A directly
B association
C link
All of the above are wrong
2. The default flow control effect of Sentienl is ____.
A fail fast
B cold start
C waiting in line
D above are all wrong
Distributed traffic protection_direct mode of flow control mode
When the QPS exceeds a certain threshold, measures are taken for flow control.
Note: If you use a flow control effect other than direct deny, the call relationship flow limit strategy (strategy) will be ignored.
Configure QPS flow control rules
Note: It means that if you query once within 1 second, it will be ok. If you query more than once, it will fail quickly and report a default error.
Test Flow Control QPS
Send request http://localhost:8001/testA
send request quickly
Distributed traffic protection_Association mode of flow control mode
what is association
When the associated resource reaches the threshold, it will limit its own flow, and when the resource B associated with A reaches the threshold, it will limit its own flow.
Configure association rules
expected result
Since the current limit control of /testA adopts QPS association, direct access will not be limited, and it will be found that there will be no current limit when refreshing /testB, as shown in the figure:
However, if you access /testA and set the QPS direct policy to limit the flow, then frequent access to /testB will show a flow limit prompt:
Real-time effect feedback
1. The following description of the Sentienl flow control mode association mode is correct _____.
A I take the blame on myself
B You take the blame yourself
C I will carry your blame
All of the above are wrong
Distributed traffic protection_ link mode of flow control mode
The link flow control mode means that when the resources coming from a certain interface meet the flow limit condition, the flow limit is enabled. Its function is somewhat similar to the configuration item for the source, the difference is that the source is for the upper-level microservice, and the link flow control is for the upper-level interface, that is to say, its granularity is finer.
Configuration example:
For example, there are two request links:
/test1 --> /common
/test2 --> /common
If you only want to count requests from /test2 to /common, you can configure it like this:
Practical case
Requirements: There are order query and order creation services, both of which need to query commodities. For the statistics of requests from querying orders to querying products, and setting a current limit.
accomplish
Add query product method
In the payment service, add a queryGoods method to the PaymentService class:
public void queryGoods(){
System.err.println("查询商品");
}
When inquiring about an order, inquire about the product
@GetMapping("/query")
public String queryOrder() {
// 查询商品
orderService.queryGoods();
// 查询订单
System.out.println("查询订单");
return "查询订单成功";
}
new order
In the PaymentController of the payment service, modify the /order/save endpoint to simulate a new order:
@GetMapping("/save")
public String saveOrder() {
// 查询商品
orderService.queryGoods();
// 查询订单
System.err.println("新增订单");
return "新增订单成功";
}Add a resource tag to the query product
By default, the methods in OrderService are not monitored by Sentinel, and we need to mark the methods to be monitored through annotations. Add the @SentinelResource annotation to the queryGoods method of OrderService:
@SentinelResource("goods")
public void queryGoods(){
System.err.println("查询商品");
}
cluster link
In link mode, two links from different sources are monitored. However, sentinel will set the same root resource for all requests entering SpringMVC by default, which will cause the link mode to fail. We need to turn off this resource aggregation for SpringMVC and modify the application.yml file.
spring:
application:
name: payment-provider-sentinel
cloud:
nacos:
discovery:
# Nacos服务地址
server-addr: 192.168.66.100:8848
sentinel:
transport:
# Sentinel控制台地址
dashboard: 192.168.66.100:8888
# sentnel api端口号 默认 8719
port: 8719
# 关闭context整合
web-context-unify: falseRestart the service, access query and save, and you can see that new resources have appeared in sentinel's cluster point link rules.
Add flow control rules
Click the flow control button behind the goods resource, and fill in the following information in the pop-up form
Real-time effect feedback
1. The following description of the link mode of Sentienl flow control mode is _____.
A for source configuration items
B fail fast
C I will carry your blame
All of the above are wrong