关于OpenResty+doujiang24/lua-resty-kafka写入kafka故障转移模拟测试

PS：文章中用到的ip和代码已脱敏

1. 环境

请查看这篇文章https://editor.csdn.net/md/?articleId=122735525

2. 配置

kafka地址：

kafka_broker_list={{host="193.168.1.2",port=9092},{host="193.168.1.3",port=9092},{host="193.168.1.1",port=9092}
}

发送脚本：

local kafka_broker_list={{host="193.168.1.2",port=9092},{host="193.168.1.3",port=9092},{host="193.168.1.1",port=9092}
}
local kafka_topic_app = "topic_app"
local p = producer:new(kafka_broker_list, {producer_type = "sync",refresh_interval=10000})
local offset, err = p:send(kafka_topic_app, nil, body)

将我的服务打包成docker image，使用的基础镜像是debian10
测试是在某个服务器上安装的docker中进行的

3. 过程

3.1 服务器上启动容器脚本

docker run -d -it -p 0.0.0.0:9000:8080 --name nginx-kafka --privileged=true nginx-kafka:0.0.1 /bin/bash

说明：

• -p 0.0.0.0:9000:8080 开放ECS（10.199.138.33）的9000端口访问，流量会转发到容器的8080端口
• --privileged=true 开放特权，否则root账户不可操作iptables

3.2 启动容器后安装iptables

apt-get install iptables -y

3.3 测试与kafka连通性

telnet 192.168.1.1 9092

telnet 192.168.1.2 9092

telnet 192.168.1.3 9092

可以看到容器到3个ip地址和端口都是通的

3.4 postman调用测试

可以看到报送请求可以被正确发送到kafka

3.5 封禁容器对 192.168.1.1 的访问

iptables -A OUTPUT -d 192.168.1.1 -j DROP

一直在尝试连接

此时nginx的error.log无任何输出。

使用postman调用报送接口：

可以看到发送kafka消息超时了。

3.6 封禁容器对 192.168.1.1，192.168.1.2 的访问

iptables -A OUTPUT -d 192.168.1.2 -j DROP

封禁后测试连通性：

发现已经连接不上了。

此时使用postman测试报送，结果和章节3.5一致。

3.7 封禁容器对 192.168.1.1，192.168.1.2，192.168.1.3 的访问

iptables -A OUTPUT -d 192.168.1.3 -j DROP

封禁后测试连通性：

发现已经连接不上了。

日志中出现了连接192.168.1.1:9092,192.168.1.2:9092，192.168.1.3:9092的报错，也有fetch_metadata的报错

2023/03/22 14:57:56 [error] 51#0: *1450 lua tcp socket connect timed out, when connecting to 192.168.1.1:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:57:56 [error] 51#0: *1450 [lua] client.lua:151: _fetch_metadata(): all brokers failed in fetch topic metadata, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:57:56 [error] 51#0: *1452 lua tcp socket connect timed out, when connecting to 192.168.1.1:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:57:56 [error] 51#0: *1452 [lua] client.lua:151: _fetch_metadata(): all brokers failed in fetch topic metadata, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:57:58 [error] 51#0: *1466 lua tcp socket connect timed out, when connecting to 192.168.1.2:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:58:00 [error] 51#0: *1469 lua tcp socket connect timed out, when connecting to 192.168.1.2:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:58:01 [error] 51#0: *1466 lua tcp socket connect timed out, when connecting to 192.168.1.3:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:58:03 [error] 51#0: *1469 lua tcp socket connect timed out, when connecting to 192.168.1.3:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:58:04 [error] 51#0: *1466 lua tcp socket connect timed out, when connecting to 192.168.1.1:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 14:58:04 [error] 51#0: *1466 [lua] client.lua:151: _fetch_metadata(): all brokers failed in fetch topic metadata, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080

此时使用postman测试报送，结果和章节3.5一致。

3.8 删除封禁 192.168.1.1

iptables -t filter -D OUTPUT -d 192.168.1.1 -j DROP

测试连通性：

发现可以联通了，此时日志输出：

2023/03/22 15:02:22 [error] 51#0: *1912 lua tcp socket connect timed out, when connecting to 192.168.1.2:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 15:02:23 [error] 51#0: *1915 lua tcp socket connect timed out, when connecting to 192.168.1.2:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 15:02:23 [error] 51#0: *1917 lua tcp socket connect timed out, when connecting to 192.168.1.2:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 15:02:25 [error] 51#0: *1912 lua tcp socket connect timed out, when connecting to 192.168.1.3:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 15:02:26 [error] 51#0: *1915 lua tcp socket connect timed out, when connecting to 192.168.1.3:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080
2023/03/22 15:02:26 [error] 51#0: *1917 lua tcp socket connect timed out, when connecting to 192.168.1.3:9092, context: ngx.timer, client: 192.168.1.4, server: 0.0.0.0:8080

使用postman测试：

奇迹般的可以访问了。

结论

1. 封禁192.168.1.1，开发其它两个ip访问时埋点报送无法发送至kafka，没能故障转移

2. 解除192.168.1.1封禁时可以正确的将埋点发送到kafka，可以认为当此ip恢复访问时，kafka可以正确的恢复。

以上结论可以类推某个ip如果一直无法访问就没法将请求消息正确发送到kafka，此ip恢复时即可正确发送到kafka