Docker pull镜像一直在Waiting无法下载，根本解决方法

1、现象描述：

docker pull 拉去镜像一直在等待，无法下载，最后失败如下：

[root@localhost docker]# docker pull zookeeper
Using default tag: latest
latest: Pulling from library/zookeeper
2ec76a50fe7c: Retrying in 1 second
fab7f202453a: Retrying in 1 second
ee59ca42def8: Retrying in 1 second
2ce2282f972f: Waiting
d2a9e456ba82: Waiting
b59edc04016d: Waiting
1e52b217ebb4: Waiting
7a5027dbe828: Waiting
4f4fb700ef54: Waiting
8e018b2f6fcb: Waiting
error pulling image configuration: download failed after attempts=6: dial tcp 199.59.148.246:443: connect: connection refused

2、现象分析：

经排查分析：

• ** 原因1：服务器DNS无法解析**
• ** 原因2：docker 源有问题**

3、解决方法：

3.1、配置并更新DNS

以CentOS7为例，直接操作哦：

vi /etc/sysconfig/network-scripts/ifcfg-eth0
DNS1=223.5.5.5
DNS2=223.6.6.6

vi /etc/resolv.conf
nameserver 223.5.5.5
nameserver 223.6.6.6
nameserver 8.8.8.8

systemctl restart network

###测试一下 是否联通
ping  223.5.5.5

3.2、更新docker源，换成国内源

sudo mkdir -p /etc/docker
sudo tee /etc/docker/daemon.json <<-'EOF'
{
  "registry-mirrors": ["https://mirror.ccs.tencentyun.com/"]
}
EOF

sudo systemctl daemon-reload
sudo systemctl restart docker

3.3、同步时间

####需安装ntp， 自行搜

ntpdate ntp1.aliyun.com

4、结果如下，6得很：

[root@localhost docker]# docker pull zookeeper
Using default tag: latest
latest: Pulling from library/zookeeper
a2abf6c4d29d: Pull complete
2bbde5250315: Pull complete
202a34e7968e: Pull complete
4e4231e30efc: Pull complete
707593b95343: Pull complete
b070e6dedb4b: Pull complete
46e5380f3905: Pull complete
8b7e330117e6: Pull complete
Digest: sha256:2c8c5c2db6db22184e197afde13e33dad849af90004c330f20b17282bcd5afd7
Status: Downloaded newer image for zookeeper:latest
docker.io/library/zookeeper:latest