您已声明Dockerfile包含RUN apt-get -yupdate其自身的RUN指令。但是,由于构建缓存,如果对Dockerfile的所有更改在文件的后面发生,则在docker build运行时,Docker将重用上次RUN apt-get-y update执行的创建的中间映像,而不是再次运行命令,因此所有最近添加或编辑的命令apt-getinstall行将使用旧数据,从而导致您观察到的错误。
有两种方法可以解决此问题:
将--no-cache选项传递给docker build,强制在每次构建映像时运行Dockerfile中的每个语句。
重写Dockerfile以将apt-get命令合并为一条RUN指令:RUN apt-get update && apt-get install foo bar ...。这样,无论何时编辑要安装的软件包列表,docker build都将被迫重新执行整个RUN指令,从而apt-get update在安装之前重新运行。
该Dockerfile最佳实践页面实际上有上一整节apt-get的Dockerfiles命令。我建议你阅读。
解决方法我的团队使用Docker(带有ubuntu:14.04基本映像)进行本地开发,我们经常不得不重建部分或全部映像。但是apt-getinstall,即使在运行后立即下载软件包,我们经常也会失败apt-get -y update。例如今天我看到
Err http://archive.ubuntu.com/ubuntu/ trusty-security/main libxml2 amd64 2.9.1+dfsg1-3ubuntu4.7 404 Not Found [IP: 91.189.88.161 80]Err http://archive.ubuntu.com/ubuntu/ trusty-security/main libxml2-dev amd64 2.9.1+dfsg1-3ubuntu4.7 404 Not Found [IP: 91.189.88.161 80]Fetched 84.7 MB in 1min 6s (1281 kB/s)Unable to correct missing packages.E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/libx/libxml2/libxml2_2.9.1+dfsg1-3ubuntu4.7_amd64.deb 404 Not Found [IP: 91.189.88.161 80]E: Failed to fetch http://archive.ubuntu.com/ubuntu/pool/main/libx/libxml2/libxml2-dev_2.9.1+dfsg1-3ubuntu4.7_amd64.deb 404 Not Found [IP: 91.189.88.161 80]E: Aborting install.
显然,特定软件包的特定版本已从存档中删除,并被命名为稍有不同的补丁程序版本取代。例如,正在寻找以上错误,libxml2_2.9.1+dfsg1-3ubuntu4.7_amd64.deb但是服务器上的版本是libxml2_2.9.1+dfsg1-3ubuntu4.8_amd64.deb。
通常,可以通过删除基本映像(docker rmiubuntu:14.04)并重建来解决此问题;新下载的ubuntu映像具有正确的补丁程序编号,并找到正确的存档文件。但这甚至不总是有效的-可能是由于新的次要升级到Ubuntu的依赖关系数据库之间的延迟与将该新ubuntu:14.04映像的部署到Docker Hub 之间存在延迟。
我们已经尝试过使用apt-get标志--fix-missing,--fix-broken而这些标志也不能始终如一地工作。
还有其他想法吗?
apt-get安装失败,并显示“未找到”错误,因为从存储库中删除的软件包是一个类似的问题,但是可接受的答案是不可接受的,因为它不可能自动化。我们的日常开发过程(包括自动构建和部署)全部使用Script编写,并使用Docker,并且每次丢失特定存档时都在Dockerfile中进行黑客入侵是不切实际的(然后在几小时或几天后删除该hack)。
作为对@ prateek05的回应,这是/etc/apt/sources.list来自官方docker ubuntu:14.04镜像的:
root@72daa1942714:/# cat /etc/apt/sources.list# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to# newer versions of the distribution.deb http://archive.ubuntu.com/ubuntu/ trusty main restricteddeb-src http://archive.ubuntu.com/ubuntu/ trusty main restricted## Major bug fix updates produced after the final release of the## distribution.deb http://archive.ubuntu.com/ubuntu/ trusty-updates main restricteddeb-src http://archive.ubuntu.com/ubuntu/ trusty-updates main restricted## Uncomment the following two lines to add software from the ’universe’## repository.## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu## team. Also,please note that software in universe WILL NOT receive any## review or updates from the Ubuntu security team.deb http://archive.ubuntu.com/ubuntu/ trusty universedeb-src http://archive.ubuntu.com/ubuntu/ trusty universedeb http://archive.ubuntu.com/ubuntu/ trusty-updates universedeb-src http://archive.ubuntu.com/ubuntu/ trusty-updates universe## N.B. software from this repository may not have been tested as## extensively as that contained in the main release,although it includes## newer versions of some applications which may provide useful features.## Also,please note that software in backports WILL NOT receive any review## or updates from the Ubuntu security team.# deb http://archive.ubuntu.com/ubuntu/ trusty-backports main restricted# deb-src http://archive.ubuntu.com/ubuntu/ trusty-backports main restricteddeb http://archive.ubuntu.com/ubuntu/ trusty-security main restricteddeb-src http://archive.ubuntu.com/ubuntu/ trusty-security main restricteddeb http://archive.ubuntu.com/ubuntu/ trusty-security universedeb-src http://archive.ubuntu.com/ubuntu/ trusty-security universe# deb http://archive.ubuntu.com/ubuntu/ trusty-security multiverse# deb-src http://archive.ubuntu.com/ubuntu/ trusty-security multiverse