解决docker镜像仓库下载慢或**Error response from daemon: Get "https://registry-1.docker.io/v2/": net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)**
解决方法
编写配置文件

将可用的镜像仓库地址写入到 daemon.json 配置文件中

 vim /etc/docker/daemon.json
 more /etc/docker/daemon.json

{
    "registry-mirrors": [
    "https://2a6bf1988cb6428c877f723ec7530dbc.mirror.swr.myhuaweicloud.com",
    "https://docker.m.daocloud.io",
    "https://hub-mirror.c.163.com",
    "https://mirror.baidubce.com",
    "https://your_preferred_mirror",
    "https://dockerhub.icu",
    "https://docker.registry.cyou",
    "https://docker-cf.registry.cyou",
    "https://dockercf.jsdelivr.fyi",
    "https://docker.jsdelivr.fyi",
    "https://dockertest.jsdelivr.fyi",
    "https://mirror.aliyuncs.com",
    "https://dockerproxy.com",
    "https://mirror.baidubce.com",
    "https://docker.m.daocloud.io",
    "https://docker.nju.edu.cn",
    "https://docker.mirrors.sjtug.sjtu.edu.cn",
    "https://docker.mirrors.ustc.edu.cn",
    "https://mirror.iscas.ac.cn",
    "https://docker.rainbond.cc"
    ]
}

重新加载一下docker的配置文件

systemctl daemon-reload

重启一下docker服务

systemctl restart docker.service

** 修改DNS服务配置**
1.如果DNS服务器出现问题，也可能导致拉取镜像报错。可以通过查看/etc/resolv.conf文件来检查DNS服务器设置：

cat /etc/resolv.conf

    2.如果显示nameserver后面没有IP地址，或者显示的IP地址有问题，可以尝试修改该文件。例如，可以将nameserver 192.168.100.2注释掉，新增nameserver 114.114.114.114和nameserver 8.8.8.8：

#nameserver 192.168.100.2
nameserver 114.114.114.114
nameserver 8.8.8.8