昨天在使用docker 时，将 image 文件从仓库抓取到本地一直报错，经过尝试，终于得以解决。
错误信息如下：
[root@archlinux ~]# docker image pull library/hello-world
Using default tag: latest
Error response from daemon: Get https://registry-1.docker.io/v2/library/hello-world/manifests/latest: dial tcp 52.20.146.203:443: i/o timeout
或者：
[root@archlinux quanxj]# docker image pull library/hello-world
Using default tag: latest
latest: Pulling from library/hello-world
ca4f61b1923c: Pull complete
error pulling image configuration: Get https://registry-1.docker.io/v2/library/hello-world/blobs/sha256:f2a91732366c0332ccd7afd2a5c4ff2b9af81f549370f7a19acd460f87686bc7: dial tcp 35.169.231.249:443: i/o timeout
解决方法如下：
**第一步：**通过dig @114.114.114.114 registry-1.docker.io找到可用IP
[root@archlinux ~]# dig @114.114.114.114 registry-1.docker.io
; <<>> DiG 9.12.0 <<>> @114.114.114.114 registry-1.docker.io
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 37534
;; flags: qr rd ra; QUERY: 1, ANSWER: 8, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
; COOKIE: 88f87a15f4ca45dc (echoed)
;; QUESTION SECTION:
;registry-1.docker.io. IN A
;; ANSWER SECTION:
registry-1.docker.io. 30 IN A 34.200.28.105
registry-1.docker.io. 30 IN A 52.22.181.254
registry-1.docker.io. 30 IN A 35.169.231.249
registry-1.docker.io. 30 IN A 52.5.185.86
registry-1.docker.io. 30 IN A 54.164.230.151
registry-1.docker.io. 30 IN A 34.200.90.16
registry-1.docker.io. 30 IN A 52.20.146.203
registry-1.docker.io. 30 IN A 52.206.156.207
;; Query time: 116 msec
;; SERVER: 114.114.114.114#53(114.114.114.114)
;; WHEN: 四 3月 08 09:27:12 CST 2018
;; MSG SIZE rcvd: 189
第二步：尝试修改/etc/hosts强制docker.io相关的域名解析到其它可用IP
vim /etc/hosts
添加一个可用IP：
52.5.185.86 registry-1.docker.io
保存之后重试:
[root@archlinux quanxj]# docker image pull library/hello-world
Using default tag: latest
latest: Pulling from library/hello-world
ca4f61b1923c: Already exists
Digest: sha256:083de497cff944f969d8499ab94f07134c50bcf5e6b9559b27182d3fa80ce3f7
Status: Downloaded newer image for hello-world:latest
验证：
[root@archlinux quanxj]# docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
hello-world latest f2a91732366c 3 months ago 1.85kB
成功！
