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Docker 热迁移探索,基于CRIU实现运行状态迁移

December 23, 2020 • Read: 503 • 编程开发

本文首发于: https://blog.frytea.com

版本限制

  • Docker: 17.06.0-ce
  • criu: 3.12
  • kernal: 3.10.0-957.el7.x86_64 || 5.10.2-1.el7.elrepo.x86_64 (Optional)
  • os: CentOS Linux release 7.9.2009 (Core) (Optional)

实测在该环境下,容器热迁移可用,热迁移成功与否与 dockercriu 版本强相关。

环境部署


# Docker 安装
$ sudo yum install -y yum-utils
$ sudo yum-config-manager \
    --add-repo \
    https://download.docker.com/linux/centos/docker-ce.repo
$ sudo yum list docker-ce --showduplicates | sort -r
$ sudo yum install docker-ce-17.06.0.ce
$ sudo systemctl start docker

# 启动Docker实验特征
vim **/etc/docker/daemon.json
+ { "experimental": true }**

# criu 安装
$ sudo yum install criu -y

# Go安装(可选)
wget https://golang.org/dl/go1.15.6.linux-amd64.tar.gz
tar -C /usr/local -xzf go1.15.6.linux-amd64.tar.gz
vim /etc/profile
+ export PATH=$PATH:/usr/local/go/bin
source /etc/profile

热迁移示例

# On the host
$ docker run -d --name looper2 --security-opt seccomp:unconfined busybox \
         /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'

# wait a few seconds to give the container an opportunity to print a few lines, then
$ docker checkpoint create looper2 checkpoint2

# check your container & print log file
$ docker logs looper2

# On the client
$ docker create --name looper-clone --security-opt seccomp:unconfined busybox \
         /bin/sh -c 'i=0; while true; do echo $i; i=$(expr $i + 1); sleep 1; done'

$ docker start --checkpoint=checkpoint2 looper-clone

# check your container
$ docekr ps
$ docker logs looper-clone

以上步骤将容器 looper2 的状态迁移到 looper-clone ,可实现当前容器、跨容器的状态迁移,甚至可以实现跨主机的迁移,只需将该目录 /var/lib/docker/{docker id}/checnkpoints/ 下面与检查点同名的文件夹迁移即可。

附件

附件一:C测试程序

/*************************************************************************
    > File Name : fork_test.c
    > Author : TL Song
    > EMail : songtianlun@frytea.com
    > Created Time : Wed 23 Dec 2020 08:46:47 AM CST
 ************************************************************************/

#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <sys/types.h>
 
int main(int arg,char* argv[]) {
 
    int i = 0;
    time_t t;
    struct tm *timeinfo;
    // int 被 typedef为 pid_t
    pid_t pid=fork();
 
    // 当pid==0时,是子进程代码运行区域。其他则是父进程运行区域。
    if(pid<0) {
        printf("Create child process failure ...\n");
    }else if(pid==0) {
        //子进程执行体
        printf("Hi i am child process ,my processId is %i \n",getpid());
        i = 0;
        while (1) {
            sleep(1);
            time(&t);
            timeinfo = localtime(&t);
            printf("Child: %d %s\n", i++, asctime(timeinfo));
            fflush(stdout);
            if(i>100)
                break;
        }
    }
    else{
        //父进程执行体
        printf("parent process is run ,myid is %i \n",getpid());
        i = 0;
        while (1) {
            sleep(1);
            time(&t);
            timeinfo = localtime(&t);
            printf("Main : %d %s\n", i++, asctime(timeinfo));
            fflush(stdout);
            if(i>100)
                break;
        }
    }
    // 执行体结束标志
    if(pid==0) {
        printf("pid=%i child process end ... \n",getpid());
    }
    else {
        // 睡眠5s,等待子先进程结束
        sleep(5);
        printf("pid=%i Parent process End ... \n",getpid());
    }
 
    return 0;
}

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