k3s

Question

尽管为它们设置了 clusterIP 服务，但我仍在为 pods 之间的这种交叉通信而苦苦挣扎。所有 pods 都在同一个主节点上，并且在同一个命名空间中。总结：

$ kubectl get pods -o wide
NAME                         READY   STATUS    RESTARTS   AGE    IP           NODE          NOMINATED NODE   READINESS GATES
nginx-744f4df6df-rxhph       1/1     Running   0          136m   10.42.0.31   raspberrypi   <none>           <none>
nginx-2-867f4f8859-csn48     1/1     Running   0          134m   10.42.0.32   raspberrypi   <none>           <none>

$ kubectl get svc -o wide
NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)                      AGE    SELECTOR
nginx-service    ClusterIP   10.43.155.201   <none>        80/TCP                       136m   app=nginx
nginx-service2   ClusterIP   10.43.182.138   <none>        85/TCP                       134m   app=nginx-2

我无法从 nginx 容器中 curl http://nginx-service2:85 ，反之亦然...虽然我从我的 docker 桌面安装：

# docker desktop
root@nginx-7dc45fbd74-7prml:/# curl http://nginx-service2:85
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

# k3s
root@nginx-744f4df6df-rxhph:/# curl http://nginx-service2.pwk3spi-vraptor:85
curl: (6) Could not resolve host: nginx-service2.pwk3spi-vraptor

在谷歌搜索问题后（如果我错了请纠正我）这似乎是一个 coredns 问题，因为查看日志并看到错误超时：

$ kubectl get pods -n kube-system
NAME                                     READY   STATUS      RESTARTS   AGE
helm-install-traefik-qr2bd               0/1     Completed   0          153d
metrics-server-7566d596c8-nnzg2          1/1     Running     59         148d
svclb-traefik-kjbbr                      2/2     Running     60         153d
traefik-758cd5fc85-wzjrn                 1/1     Running     20         62d
local-path-provisioner-6d59f47c7-4hvf2   1/1     Running     72         148d
coredns-7944c66d8d-gkdp4                 1/1     Running     0          3m47s

$ kubectl logs coredns-7944c66d8d-gkdp4 -n kube-system
.:53
[INFO] plugin/reload: Running configuration MD5 = 1c648f07b77ab1530deca4234afe0d03
CoreDNS-1.6.9
linux/arm, go1.14.1, 1766568
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:50482->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:34160->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:53485->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:46642->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:55329->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:44471->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:49182->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:54082->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:48151->192.168.8.109:53: i/o timeout
[ERROR] plugin/errors: 2 1898797220.1916943194. HINFO: read udp 10.42.0.38:48599->192.168.8.109:53: i/o timeout

人们推荐的地方

更改 coredns 配置映射以转发到您的主节点 IP

... other CoreFile stuff

forward . host server IP

... other CoreFile stuff

或将您的 coredns clusterip IP 作为名称服务器添加到 /etc/resolve.conf

search default.svc.cluster.local svc.cluster.local cluster.local

nameserver 10.42.0.38

nameserver 192.168.8.1

nameserver fe80::266:19ff:fea7:85e7%wlan0

，但是没有发现这些解决方案有效。

详情供参考：

$ kubectl get nodes -o wide
NAME          STATUS   ROLES    AGE    VERSION        INTERNAL-IP     EXTERNAL-IP   OS-IMAGE                         KERNEL-VERSION   CONTAINER-RUNTIME
raspberrypi   Ready    master   153d   v1.18.9+k3s1   192.168.8.109   <none>        Raspbian GNU/Linux 10 (buster)   5.10.9-v7l+      containerd://1.3.3-k3s2

$ kubectl get svc -n kube-system -o wide
NAME                 TYPE           CLUSTER-IP      EXTERNAL-IP     PORT(S)                      AGE    SELECTOR
kube-dns             ClusterIP      10.43.0.10      <none>          53/UDP,53/TCP,9153/TCP       153d   k8s-app=kube-dns
metrics-server       ClusterIP      10.43.205.8     <none>          443/TCP                      153d   k8s-app=metrics-server
traefik-prometheus   ClusterIP      10.43.222.138   <none>          9100/TCP                     153d   app=traefik,release=traefik
traefik              LoadBalancer   10.43.249.133   192.168.8.109   80:31222/TCP,443:32509/TCP   153d   app=traefik,release=traefik

$ kubectl get ep kube-dns -n kube-system
NAME       ENDPOINTS                                     AGE
kube-dns   10.42.0.38:53,10.42.0.38:9153,10.42.0.38:53   153d

不知道我哪里出错了，或者我是否专注于错误的事情，或者如何继续。如有任何帮助，我们将不胜感激。

Answer 1

您尝试卷曲此地址是否有原因：

curl http://nginx-service2.pwk3spi-vraptor:85

这不应该只是：

curl http://nginx-service2:85

Answer 2

当所有其他方法都失败时......返回手册。我试图在所有错误的地方找到 'issue'，而我只需要按照 Rancher 的 k3s 安装文档（叹气）。

Rancher's documentation 非常好（你只需要真正遵循它），他们说在 Raspbian Buster 环境 [= 上安装 k3s 时16=]

check version:

$ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 10 (buster)
Release:        10
Codename:       buster

您需要更改为 legacy iptables，声明为运行 (link):

sudo iptables -F
sudo update-alternatives --set iptables /usr/sbin/iptables-legacy
sudo update-alternatives --set ip6tables /usr/sbin/ip6tables-legacy
sudo reboot

note that when setting the iptables, do it directly on the pi, not via ssh. You will be kicked out

这样做之后，我所有的服务都很满意，并且可以通过它们定义的 clusterIP 服务名称等从容器内相互 curl。

Answer 3

对于那些不想像我一样在 centos 上使用 k3s 浪费 3 个小时的人，你需要禁用防火墙才能让这些服务相互调用

https://rancher.com/docs/k3s/latest/en/advanced/#additional-preparation-for-red-hat-centos-enterprise-linux

建议关闭firewalld:

systemctl disable firewalld --now

如果启用，需要禁用nm-cloud-setup并重启节点：

systemctl disable nm-cloud-setup.service nm-cloud-setup.timer
reboot

在我禁用它之后，服务能够通过我的配置中的 dns 名称相互调用

仍在寻找禁用防火墙的更好方法，但这取决于 k3s 项目的开发人员

k3s - pods 之间的网络不工作

k3s - networking between pods not working

kubernetes

coredns