Docker基础知识--namespace cgroup

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记录一下docker基础知识

namespace是环境隔离，cgroup是资源隔离，加起来就是docker的基础

namespace

  1. CLONE_NEWPID
  2. CLONE_NEWUTS
  3. CLONE_NEWNS
  4. CLONE_NEWIPC
  5. CLONE_NEWNET
  6. CLONE_NEWUSER

不带namespace

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#define _GNU_SOURCE
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/wait.h>
#include <unistd.h>

//子进程堆栈空间大小
#define STACK_SIZE (1024 * 1024)

static char child_stack[STACK_SIZE];

char* const child_cmd[] = {
    "/bin/bash",
    NULL
};

int child()
{
    printf("Child start!\n");
    printf("Child pid in child process: %5d\n", getpid());
    //使用bash替换掉原进程便于观察
    execv(child_cmd[0], child_cmd);
    printf("Child stop!\n");
    return 0;
}

int main()
{
    printf("Parent start!\n");
    printf("Parent pid: %5d\n", getpid());
    int child_pid = clone(child, child_stack+STACK_SIZE, SIGCHLD, NULL);
    printf("Child pid in parent process: %5d\n", child_pid);
    waitpid(child_pid, NULL, 0);
    printf("Parent stop!\n");
    return 0;
}

结果

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i3@i3:~/code/namespace$ ./base
Parent start!
Parent pid:  7816
Child pid in parent process:  7817
Child start!
Child pid in child process:  7817

UTS

cgroup

参考

https://yq.aliyun.com/articles/57743
http://coolshell.cn/articles/17049.html

本博客欢迎转发,但请保留原作者信息
github:codejuan
博客地址:http://blog.decbug.com/