docker構建國內映象服務
在國內想要下載映象比較困難，因此很多公司都構建自己的私有倉庫。如何搭建私有倉庫，請參考《docker私有倉庫從無到有》。然而即使私有倉庫服務構建完成，但是裡面沒有映象，一樣很苦惱。今天介紹一下如何利用國內雲服務商提供的映象加速器，來快速下載映象。
目前國內docker映象加速器服務商，質量比較好的有阿里雲、DaoCloud以及Docker中國。
它們配置都是相同，獲取專屬加速地址，然後將地址寫到docker配置檔案/etc/docker/daemon.json中。
一、阿里雲加速地址：
1、註冊阿里雲賬號，如果有淘寶號也是可以的。https://dev.aliyun.com/search.html
2、註冊並登陸成功之後，進入之後點選管理中心
3、進入管理中心，預設業務就是下圖，然後在選擇映象加速器，裡面就是專屬加速地址，並且有配置方法。
DaoCloud配置方式與阿里雲類似，只是服務商不一樣罷了。
二、Docker中國如果不想註冊阿里雲，那麼可以使用Docker中國提供的服務。
可以將https://registry.docker-cn.com，設定到registry-mirrors中即可（與阿里雲設定方式一樣）。具體方法，可參考https://www.docker-cn.com/registry-mirror。
以上設定好映象之後，不需要docker login進行登入。
三、遇到問題
問題1：設定完加速地址之後，輸入如下命令：
[[email protected] docker]# docker pull mysql
Using default tag: latest
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)
[[email protected] docker]#
[[email protected] 檢視具體日誌資訊：
[[email protected] docker]# grep docker /var/log/messages
Mar 7 15:59:06 localhost dockerd: time="2018-03-07T15:59:06.551882623+08:00" level=warning msg="Error getting v2 registry: Get https://6jwksk60.mirror.aliyuncs.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:06 localhost dockerd: time="2018-03-07T15:59:06.551997545+08:00" level=error msg="Not continuing with pull after error: Get https://6jwksk60.mirror.aliyuncs.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:06 localhost dockerd: time="2018-03-07T15:59:06.552080576+08:00" level=error msg="Handler for POST /v1.35/images/create returned error: Get https://6jwksk60.mirror.aliyuncs.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:08 localhost dockerd: time="2018-03-07T15:59:08.441427015+08:00" level=debug msg="Calling GET /_ping"
Mar 7 15:59:08 localhost dockerd: time="2018-03-07T15:59:08.449887376+08:00" level=debug msg="Calling GET /v1.35/info"
Mar 7 15:59:08 localhost dockerd: time="2018-03-07T15:59:08.485088164+08:00" level=debug msg="Calling POST /v1.35/images/create?fromImage=mysql&tag=latest"
Mar 7 15:59:08 localhost dockerd: time="2018-03-07T15:59:08.547151332+08:00" level=debug msg="hostDir: /etc/docker/certs.d/6jwksk60.mirror.aliyuncs.com"
Mar 7 15:59:08 localhost dockerd: time="2018-03-07T15:59:08.547231472+08:00" level=debug msg="Trying to pull mysql from https://6jwksk60.mirror.aliyuncs.com/ v2"
Mar 7 15:59:23 localhost dockerd: time="2018-03-07T15:59:23.548000137+08:00" level=warning msg="Error getting v2 registry: Get https://6jwksk60.mirror.aliyuncs.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:23 localhost dockerd: time="2018-03-07T15:59:23.548084051+08:00" level=info msg="Attempting next endpoint for pull after error: Get https://6jwksk60.mirror.aliyuncs.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:23 localhost dockerd: time="2018-03-07T15:59:23.548133902+08:00" level=debug msg="Trying to pull mysql from https://registry-1.docker.io v2"
Mar 7 15:59:38 localhost dockerd: time="2018-03-07T15:59:38.548628804+08:00" level=warning msg="Error getting v2 registry: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:38 localhost dockerd: time="2018-03-07T15:59:38.548715275+08:00" level=info msg="Attempting next endpoint for pull after error: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
Mar 7 15:59:38 localhost dockerd: time="2018-03-07T15:59:38.548798878+08:00" level=error msg="Handler for POST /v1.35/images/create returned error: Get https://registry-1.docker.io/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"實際錯誤是：
Get https://6jwksk60.mirror.aliyuncs.com/v2/: net/http: request canceled while waiting for connection (Client.Timeout exceeded while awaiting headers)"
【定位過程】通過谷歌翻牆（百度不行，解決不了這個問題），一共大概有兩種方式
1、設定dns，在/etc/resolv.conf，以及/etc/docker/daemon.json中增加dns。例如dns地址：8.8.8.8
2、設置docker代理（centos和ubuntu同樣設定）
[[email protected] docker]# mkdir -p /etc/systemd/system/docker.service.d
[[email protected] docker]# cat > /etc/systemd/system/docker.service.d/http-proxy.conf <<EOF
> [Service]
> Environment="HTTP_PROXY=http://proxy.example.com:80/" "HTTPS_PROXY=https://proxy.example.com:443/"
> EOF
[[email protected] docker]#然後重啟服務
[[email protected] docker]# systemctl daemon-reload
[[email protected] docker]# systemctl restart docker檢視配置
[[email protected] docker]# systemctl show --property=Environment docker
Environment=HTTP_PROXY=http://proxy.example.com:80/ HTTPS_PROXY=https://proxy.example.com:443/
[[email protected] docker]# 設定完成後再進行docker pull就可以下載了。
【分析一下原因】
1、通過curl來判斷服務是正常的，所以肯定是docker配置問題。
2、當前環境在公司內網，公司是有代理的，因此可以肯定是公司網路問題，通過谷歌搜尋，最終確定需要為docker指定代理。