k8s中service自动为pod增加环境引起的bug

起因

今天为一个测试服务增加实例,发现启动不起来了,但原来的有的实例正常运行,把正常的pod删除后,所有pod都异常了。具体如图:

排查

查看pod日志:

1kubectl logs -f whoami-85f458667c-f5nw9
22023/06/02 02:24:31 listen tcp: address :tcp://10.101.156.195:8080: too many colons in address

发现是端口不对导致

查看部署文件:

1kubectl get deploy whoami -oyaml

发现并没有对env进行设置,查看whoami源码,发现port是受环境变量WHOAMI_PORT控制

https://github.com/freemesh/whoami/blob/main/main.go

查看问题pod的环境变量

进入问题pod所在机器,查看容器的详细信息,发现ENV下有很多环境变量,其中就包括WHOAMI_PORT

 1docker inspect 0c842287ada4
 2
 3"Env": [
 4    "NGINX_SERVICE_PORT=8080",
 5    "NGINX_PORT_8080_TCP_PROTO=tcp",
 6    "NGINX_PORT_8080_TCP_PORT=8080",
 7    "MY_INGRESS_SERVICE_HOST=10.101.163.141",
 8    "KUBERNETES_SERVICE_PORT=443",
 9    "NGINX_PORT_8080_TCP_ADDR=10.105.237.147",
10    "MY_INGRESS_PORT_8080_TCP_PROTO=tcp",
11    "ENVTEST_SERVICE_PORT=8080",
12    "ENVTEST_PORT_8080_TCP_PORT=8080",
13    "KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443",
14    "KUBERNETES_PORT_443_TCP_PORT=443",
15    "WHOAMI_SERVICE_PORT=8080",
16    "WHOAMI_PORT_8080_TCP_ADDR=10.101.156.195",
17    "WHOAMI_PORT_8080_TCP=tcp://10.101.156.195:8080",
18    "WHOAMI_PORT_8080_TCP_PROTO=tcp",
19    "NGINX_SERVICE_HOST=10.105.237.147",
20    "MY_INGRESS_PORT=tcp://10.101.163.141:8080",
21    "MY_INGRESS_PORT_8080_TCP_ADDR=10.101.163.141",
22    "ENVTEST_PORT_8080_TCP_PROTO=tcp",
23    "KUBERNETES_SERVICE_PORT_HTTPS=443",
24    "WHOAMI_PORT=tcp://10.101.156.195:8080",  #这个就是程序里用到的环境变量
25    "MY_INGRESS_SERVICE_PORT=8080",
26    "MY_INGRESS_PORT_8080_TCP=tcp://10.101.163.141:8080",
27    "MY_INGRESS_PORT_8080_TCP_PORT=8080",
28    "ENVTEST_PORT=tcp://10.101.53.28:8080",
29    "KUBERNETES_SERVICE_HOST=10.96.0.1",
30    "KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1",
31    "NGINX_PORT=tcp://10.105.237.147:8080",
32    "ENVTEST_SERVICE_HOST=10.101.53.28",
33    "ENVTEST_PORT_8080_TCP=tcp://10.101.53.28:8080",
34    "WHOAMI_SERVICE_HOST=10.101.156.195",
35    "WHOAMI_PORT_8080_TCP_PORT=8080",
36    "NGINX_PORT_8080_TCP=tcp://10.105.237.147:8080",
37    "ENVTEST_PORT_8080_TCP_ADDR=10.101.53.28",
38    "KUBERNETES_PORT=tcp://10.96.0.1:443",
39    "KUBERNETES_PORT_443_TCP_PROTO=tcp",
40    "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
41],

原因

原来,我们创建servicer的时候,k8s会自动为pod增加svc的环境变量,我们可以在pod.spec增加 enableServiceLinks:false 来关闭这项特性。

参考 https://kubernetes.io/docs/tutorials/services/connect-applications-service/#accessing-the-service

pod配置详解见: k8s的pod.yaml文件配置详解

解决

1kubectl edit deploy whoami

spec.template.spec下增加enableServiceLinks:false发现pod可以正常运行了。

PS

什么样的服务有会向pod添加env

对于无头服务clusterIP: None的service不会添加env

全局关闭

询问chatGPT,是否可以全局关闭:

修改apiservers配置

1vi /etc/kubernetes/manifests/kube-apiserver.yaml

按这个方法,apiserver启动报错:

1docker logs -f c5b494249fe3
2Error: unknown flag: --enable-service-links

查看kube-apiserver也没这个参数,gpt也会忽悠,估计是不能全局关闭了。

https://kubernetes.io/zh-cn/docs/reference/command-line-tools-reference/kube-apiserver/

发布日期:2023-06-01 19:31 字数:146 用时 1分钟
tags:k8s