kubernetes nginx 上游服务器作为服务未找到

Question

这些是here (kubernetes.io/docs)引用的我的yaml文件

deployment gists

我使用命令kubectl apply -f backend-deployment.yaml -f frontend-configmap.yaml -f frontend-deployment.yaml

后端启动成功，但前端出现错误。

[emerg] 1#1: host not found in upstream "backend-service" in /etc/nginx/conf.d/nginx.conf:2
#nginx: [emerg] host not found in upstream "backend-service" in /etc/nginx/conf.d/nginx.conf:2

即使声明了'backend-service'，nginx也无法识别它。

命令nslookup backend-service 结果是：

Server:         127.0.0.53
Address:        127.0.0.53#53

** server can't find backend-service: SERVFAIL

我错过了什么？

Answer 1

我已经更接近问题/解决方案了。

首先，如果您提供的答案中的图像是正确的，那么您在后端部署中运行 nginx，在前端部署中运行 node-js 服务器。这是一个错误。

更改图像后，前端正在运行（如预期的那样）但后端 pod 正在崩溃。

但是，后端 pod 已成功将 mysql-service 解析为其内部 clusterIp，而我的身份验证设置似乎有误。

`> server@1.0.0 start /usr/src/app
 > node backend.js
 
 (node:18) Warning: Accessing non-existent property 'count' of module exports inside circular dependency
 (Use `node --trace-warnings ...` to show where the warning was created)
 (node:18) Warning: Accessing non-existent property 'findOne' of module exports inside circular dependency
 (node:18) Warning: Accessing non-existent property 'remove' of module exports inside circular dependency
 (node:18) Warning: Accessing non-existent property 'updateOne' of module exports inside circular dependency
 listening on 3000
 events.js:292
       throw er; // Unhandled 'error' event
       ^
 
 Error: connect ECONNREFUSED 10.100.77.32:3306
     at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1142:16)
     --------------------
     at Protocol._enqueue (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:144:48)
     at Protocol.handshake (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:51:23)
     at Connection.connect (/usr/src/app/node_modules/mysql/lib/Connection.js:116:18)
     at Object.<anonymous> (/usr/src/app/backend.js:58:12)
     at Module._compile (internal/modules/cjs/loader.js:1185:30)
     at Object.Module._extensions..js (internal/modules/cjs/loader.js:1205:10)
     at Module.load (internal/modules/cjs/loader.js:1034:32)
     at Function.Module._load (internal/modules/cjs/loader.js:923:14)
     at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)
     at internal/main/run_main_module.js:17:47
 Emitted 'error' event on Connection instance at:
     at Connection._handleProtocolError (/usr/src/app/node_modules/mysql/lib/Connection.js:423:8)
     at Protocol.emit (events.js:315:20)
     at Protocol._delegateError (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:398:10)
     at Handshake.<anonymous> (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:153:12)
     at Handshake.emit (events.js:315:20)
     at Handshake.Sequence.end (/usr/src/app/node_modules/mysql/lib/protocol/sequences/Sequence.js:78:12)
     at Protocol.handleNetworkError (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:369:14)
     at Connection._handleNetworkError (/usr/src/app/node_modules/mysql/lib/Connection.js:418:18)
     at Socket.emit (events.js:315:20)
     at emitErrorNT (internal/streams/destroy.js:96:8)
     at emitErrorCloseNT (internal/streams/destroy.js:68:3)
     at processTicksAndRejections (internal/process/task_queues.js:84:21) {
   errno: -111,
   code: 'ECONNREFUSED',
   syscall: 'connect',
   address: '10.100.77.32',
   port: 3306,
 > node backend.js
   fatal: true
 }
 npm ERR! code ELIFECYCLE
 npm ERR! errno 1
 npm ERR! server@1.0.0 start: `node backend.js`
 npm ERR! Exit status 1
 npm ERR! 
 npm ERR! Failed at the server@1.0.0 start script.
 npm ERR! This is probably not a problem with npm. There is likely additional logging output above.
 
 npm ERR! A complete log of this run can be found in:
 npm ERR!     /root/.npm/_logs/2021-07-21T08_46_32_833Z-debug.log`

如果您查看日志。它说它试图连接到 10.100.77.32:3306 并且 kubectl get svc 的输出如下mysql-service ClusterIP 10.100.77.32 <none> 3306/TCP 17m

与我的服务的匹配 ip。

kubectl get endpoints 表明 mysql-service 确实找到了一个端点：

mysql-service      ClusterIP   10.100.77.32     <none>        3306/TCP       17m

这里是额外的日志信息，显示您的 nodejs 应用程序的身份验证机制似乎不适用于 mysql pod。

  Error: ER_NOT_SUPPORTED_AUTH_MODE: Client does not support authentication protocol requested by server; consider upgrading MySQL client
    at Handshake.Sequence._packetToError (/usr/src/app/node_modules/mysql/lib/protocol/sequences/Sequence.js:47:14)
    at Handshake.ErrorPacket (/usr/src/app/node_modules/mysql/lib/protocol/sequences/Handshake.js:123:18)
    at Protocol._parsePacket (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:291:23)
    at Parser._parsePacket (/usr/src/app/node_modules/mysql/lib/protocol/Parser.js:433:10)
    at Parser.write (/usr/src/app/node_modules/mysql/lib/protocol/Parser.js:43:10)
    at Protocol.write (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:38:16)
    at Socket.<anonymous> (/usr/src/app/node_modules/mysql/lib/Connection.js:88:28)
    at Socket.<anonymous> (/usr/src/app/node_modules/mysql/lib/Connection.js:526:10)
    at Socket.emit (events.js:315:20)
    at addChunk (_stream_readable.js:296:12)
    at readableAddChunk (_stream_readable.js:272:9)
    at Socket.Readable.push (_stream_readable.js:213:10)
    at TCP.onStreamRead (internal/stream_base_commons.js:186:23)
    --------------------
    at Protocol._enqueue (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:144:48)
    at Protocol.handshake (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:51:23)
    at Connection.connect (/usr/src/app/node_modules/mysql/lib/Connection.js:116:18)
    at Object.<anonymous> (/usr/src/app/backend.js:58:12)
    at Module._compile (internal/modules/cjs/loader.js:1185:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1205:10)
    at Module.load (internal/modules/cjs/loader.js:1034:32)
    at Function.Module._load (internal/modules/cjs/loader.js:923:14)
    at Function.executeUserEntryPoint [as runMain] (internal/modules/run_main.js:71:12)
    at internal/main/run_main_module.js:17:47
Emitted 'error' event on Connection instance at:
    at Connection._handleProtocolError (/usr/src/app/node_modules/mysql/lib/Connection.js:423:8)
    at Protocol.emit (events.js:315:20)
    at Protocol._delegateError (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:398:10)
    at Handshake.<anonymous> (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:153:12)
    at Handshake.emit (events.js:315:20)
    at Handshake.Sequence.end (/usr/src/app/node_modules/mysql/lib/protocol/sequences/Sequence.js:78:12)
    at Handshake.ErrorPacket (/usr/src/app/node_modules/mysql/lib/protocol/sequences/Handshake.js:125:8)
    at Protocol._parsePacket (/usr/src/app/node_modules/mysql/lib/protocol/Protocol.js:291:23)
    [... lines matching original stack trace ...]
    at readableAddChunk (_stream_readable.js:272:9) {
  code: 'ER_NOT_SUPPORTED_AUTH_MODE',
  errno: 1251,
  sqlMessage: 'Client does not support authentication protocol requested by server; consider upgrading MySQL client',
  sqlState: '08004',
  fatal: true
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! server@1.0.0 start: `node backend.js`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the server@1.0.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2021-07-21T08_55_22_133Z-debug.log

但是，随着答案开头所建议的更改，应该解决有关解析服务名称和在 kubernetes 内部通信的问题。

Answer 2

后端部署镜像：bateaux/test-nginx

前端部署映像：bataux/test-node-server

在部署 backend-deployment 时，移除 [livenessProbe, readinessProbe]。

因为node.js express server使用@cloudnative/health-connect来做readinessProbe，所以调用PingCheck(worker node ip)。

Answer 3

哇....我找到了getaddrinfo EAI_AGAIN mysql-service 的解决方案。

我认为如果网络找不到服务，则 dns 有错误。

kubectl logs --namespace=kube-system -l k8s-app=kube-dns

命令的结果是gist。

所以...我终于找到了这个关于 kubernetes coredns 的link。

根据belphegor的回答，它可以重新启动coredns。

虽然有新错误Client does not support authentication protocol requested by server; consider upgrading MySQL client，但我认为解决它比 dns 错误更容易。哈哈哈哈哈哈哈哈哈