问题描述：
在centos7系统上使用命令yum -y install docker安装的docker，在下载镜像的时候速度非常慢，最后镜像下载失败，报“net/http: TLS handshake timeout”的错误：
[root@localhost ~]# docker run -d --restart=unless-stopped -p 8080:8080 -p 9345:9345 rancher/server:stable --db-host 10.0.0.101 --db-port 3306 --db-user rancher --db-pass rancher --db-name rancher --advertise-address 10.0.0.103
Unable to find image 'rancher/server:stable' locally
Trying to pull repository docker.io/rancher/server ...
stable: Pulling from docker.io/rancher/server
bae382666908: Pulling fs layer
29ede3c02ff2: Pulling fs layer
da4e69f33106: Pulling fs layer
8d43e5f5d27f: Waiting
b0de1abb17d6: Waiting
422f47db4517: Waiting
79d37de643ce: Waiting
69d13e08a4fe: Waiting
2ddfd3c6a2b7: Waiting
bc433fed3823: Waiting
b82e188df556: Waiting
dae2802428a4: Waiting
a6247572ea3c: Waiting
884c916ebae4: Waiting
85517c9c5365: Waiting
02dded9fe690: Waiting
fd9f433c3bc6: Waiting
44d91b3fea45: Waiting
0d463387dfeb: Waiting
60753c4d26f0: Waiting
a003892966fe: Waiting
/usr/bin/docker-current: error pulling image configuration: Get https://dseasb33srnrn.cloudfront.net/registry-v2/docker/registry/v2/blobs/sha256/d6/d63b9b4bd2059242e826eaf0cbc879d5728a82cb6ddcd9dcd844bb9257f3fd0a/data?Expires=1521809033&Signature=JBuzPXx14~-I6-mnzBMR5d4At3sU~0TszPc8dhNI45ORRxk8DLXzK-aU3AZk~J-pHdXJ3q6w7w9Y6-WFU8M36FRxFDZC8xwWZE-KVZtZg8mcjC~vAbPiq8RQaSXuk9IieIkTfYoC4mUt2N~lWM34dGuOoyGyuEEIVWISVxu8Uus_&Key-Pair-Id=APKAJECH5M7VWIS5YZ6Q: net/http: TLS handshake timeout.
See '/usr/bin/docker-current run --help'.
[root@localhost ~]# 原因分析：
docker默认镜像拉取地址为国外仓库下载速度较慢，则会报错“net/http: TLS handshake timeout”。
此时，只需要将拉取地址改为国内镜像仓库即可。
解决过程：
在docker配置文件/etc/sysconfig/docke的OPTIONS中添加“--registry-mirror=https://fzhifedh.mirror.aliyuncs.com”
[root@localhost ~]# vim /etc/sysconfig/docker
# /etc/sysconfig/docker
# Modify these options if you want to change the way the docker daemon runs
#OPTIONS='--selinux-enabled --log-driver=journald --signature-verification=false'
OPTIONS='--selinux-enabled --log-driver=journald --signature-verification=false --registry-mirror=https://fzhifedh.mirror.aliyuncs.com ' #换默认源地址
#DOCKER_OPTS="$DOCKER_OPTS --registry-mirror=http://f2d6cb40.m.daocloud.io"
if [ -z "${DOCKER_CERT_PATH}" ]; then
DOCKER_CERT_PATH=/etc/docker
fi
# Do not add registries in this file anymore. Use /etc/containers/registries.conf
# from the atomic-registries package.
#然后重新下载镜像，速度很快，而且正常了：
[root@localhost ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6e3e55edcc21 rancher/server:stable "/usr/bin/entry --..." 9 minutes ago Up 9 minutes 3306/tcp, 0.0.0.0:9345->9345/tcp, 0.0.0.0:8080->8080/tcp flamboyant_haibt
[root@localhost ~]#