通过 TCP 连接在没有服务的同一集群中连接 Kubernetes Pods

Question

我一直在尝试寻找不同的方法来连接 kubernetes pods。我最初使用服务和 NodePort 连接连接了两个 pods。现在我正在尝试使用 tcp 套接字这样做。

kubectl get pod -o wide
NAME   READY   STATUS    RESTARTS   AGE     IP              NODE    NOMINATED NODE   READINESS GATES
f1     1/1     Running   4          2d18h   10.233.90.120   node1   <none>           <none>
f2     1/1     Running   4          2d18h   10.233.90.117   node1   <none>           <none>

我可以看到我尝试使用 tcp 套接字连接的这两个 Ips，将它们与 tcp 端口 8080 绑定。但是它显示它没有连接。

我想这不是使用 tcp 套接字连接它们的方法。有什么方法可以使用 tcp 套接字制作一个 pod 服务器和其他 pod 客户端并连接。

编辑：

我附上 server.c 和 client.c 这两个文件以供参考。我尝试使用集群名称 f1 和 f2 但是仍然面临的错误是

root@node1:~/socket# ./server
Socket successfully created..
socket bind failed...

我还附加了 f1.yaml 和 f2.yaml 文件。

f1.yaml

apiVersion: v1
kind: Pod
metadata:
  name: f1
  labels:
    role: f1
spec:
  containers:
    - name: web
      image: nginx
      ports:
        - name: web
          containerPort: 80
          protocol: TCP

f2.yaml

apiVersion: v1
kind: Pod
metadata:
  name: f2
  labels:
    role: f2
spec:
  containers:
    - name: f2
      image: "gcr.io/google-samples/hello-go-gke:1.0"
      ports:
        - name: web
          containerPort: 80
          protocol: TCP

server.c

  #include <stdio.h> 
#include <netdb.h> 
#include <netinet/in.h> 
#include <stdlib.h> 
#include <string.h> 
#include <sys/socket.h> 
#include <sys/types.h> 
#define MAX 80 
#define PORT 8080 
#define SA struct sockaddr 
  
// Function designed for chat between client and server. 
void func(int sockfd) 
{ 
    char buff[MAX]; 
    int n; 
    // infinite loop for chat 
    for (;;) { 
        bzero(buff, MAX); 
  
        // read the message from client and copy it in buffer 
        read(sockfd, buff, sizeof(buff)); 
        // print buffer which contains the client contents 
        printf("From client: %s\t To client : ", buff); 
        bzero(buff, MAX); 
        n = 0; 
        // copy server message in the buffer 
        while ((buff[n++] = getchar()) != '\n') 
            ; 
  
        // and send that buffer to client 
        write(sockfd, buff, sizeof(buff)); 
  
        // if msg contains "Exit" then server exit and chat ended. 
        if (strncmp("exit", buff, 4) == 0) { 
            printf("Server Exit...\n"); 
            break; 
        } 
    } 
} 
  
// Driver function 
int main() 
{ 
    int sockfd, connfd, len; 
    struct sockaddr_in servaddr, cli; 
  
    // socket create and verification 
    sockfd = socket(AF_INET, SOCK_STREAM, 0); 
    if (sockfd == -1) { 
        printf("socket creation failed...\n"); 
        exit(0); 
    } 
    else
        printf("Socket successfully created..\n"); 
    bzero(&servaddr, sizeof(servaddr)); 
  
    // assign IP, PORT 
    servaddr.sin_family = AF_INET; 
//    servaddr.sin_addr.s_addr = htonl(INADDR_ANY); 
    servaddr.sin_addr.s_addr = htonl("f1"); 
    servaddr.sin_port = htons(PORT); 
  
    // Binding newly created socket to given IP and verification 
    if ((bind(sockfd, (SA*)&servaddr, sizeof(servaddr))) != 0) { 
        printf("socket bind failed...\n"); 
        exit(0); 
    } 
    else
        printf("Socket successfully binded..\n"); 
  
    // Now server is ready to listen and verification 
    if ((listen(sockfd, 5)) != 0) { 
        printf("Listen failed...\n"); 
        exit(0); 
    } 
    else
        printf("Server listening..\n"); 
    len = sizeof(cli); 
  
    // Accept the data packet from client and verification 
    connfd = accept(sockfd, (SA*)&cli, &len); 
    if (connfd < 0) { 
        printf("server acccept failed...\n"); 
        exit(0); 
    } 
    else
        printf("server acccept the client...\n"); 
  
    // Function for chatting between client and server 
    func(connfd); 
  
    // After chatting close the socket 
    close(sockfd); 
}

client.c

#include <netdb.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <string.h> 
#include <sys/socket.h> 
#define MAX 80 
#define PORT 8080
#define SA struct sockaddr 
void func(int sockfd) 
{ 
    char buff[MAX]; 
    int n; 
    for (;;) { 
        bzero(buff, sizeof(buff)); 
        printf("Enter the string : "); 
        n = 0; 
        while ((buff[n++] = getchar()) != '\n') 
            ; 
        write(sockfd, buff, sizeof(buff)); 
        bzero(buff, sizeof(buff)); 
        read(sockfd, buff, sizeof(buff)); 
        printf("From Server : %s", buff); 
        if ((strncmp(buff, "exit", 4)) == 0) { 
            printf("Client Exit...\n"); 
            break; 
        } 
    } 
} 

int main() 
{ 
    int sockfd, connfd; 
    struct sockaddr_in servaddr, cli; 

    // socket create and varification 
    sockfd = socket(AF_INET, SOCK_STREAM, 0); 
    if (sockfd == -1) { 
        printf("socket creation failed...\n"); 
        exit(0); 
    } 
    else
        printf("Socket successfully created..\n"); 
    bzero(&servaddr, sizeof(servaddr)); 

    // assign IP, PORT 
    servaddr.sin_family = AF_INET; 
//  servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    servaddr.sin_addr.s_addr = inet_addr("f2"); 
    servaddr.sin_port = htons(PORT); 

    // connect the client socket to server socket 
    if (connect(sockfd, (SA*)&servaddr, sizeof(servaddr)) != 0) { 
        printf("connection with the server failed...\n"); 
        exit(0); 
    } 
    else
        printf("connected to the server..\n"); 

    // function for chat 
    func(sockfd); 

    // close the socket 
    close(sockfd); 
}

Answer 1

如果您想将一个 Pod 连接到另一个 Pod，您可以使用它们的内部 Pod IP（10.233.90.120、10.233.90.117）或它们的 Pod 名称 f1、f2 （应该自动将 DNS 解析为其内部 Pod IP）。你不应该有任何问题。而且您不需要为此提供任何服务。如果他们无法连接，请添加他们的日志和代码运行。

如果你想从 Kubernetes 集群外部连接到 Pods，那么你需要将它们公开：

NodePort/LoadBalancer 服务或
Kubectl 端口转发

您应该始终能够建立 TCP 套接字连接。

通过 TCP 连接在没有服务的同一集群中连接 Kubernetes Pods

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