apt-get不能安装python-nova的特定旧版本。

Question

还有一个类似的问题，获取无法安装apt-缓存策略中列出的特定版本.。但这不是我的案子。

我想安装python的特定旧版本(1:2013.2.3-0ubuntu1~cloud0)，但失败了，这是我所做的：

root@ip-10-20-17:~# apt-cache policy python-nova
python-nova:
  Installed: (none)
  Candidate: 1:2014.1.3-0ubuntu1~cloud0.1
  Version table:
     1:2014.1.3-0ubuntu1~cloud0.1 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud0-5 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud0-4 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud0-2 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud0~-1 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud063 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud062 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud061 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2014.1.2-0ubuntu1.1~cloud0~3 0
        900 http://apt.myserver.com/game-cloud-ops/ precise/main amd64 Packages
     1:2013.2.3-0ubuntu1~cloud0 0
        -10 http://apt.myserver.com/ubuntu-cloud-archive/ precise-updates/havana/main amd64 Packages
     2012.1.3+stable-20130423-e52e6912-0ubuntu1.4 0
        900 http://mirror.myserver.com/ubuntu/ precise-security/main amd64 Packages
        900 http://mirror.myserver.com/ubuntu/ precise-updates/main amd64 Packages
     2012.1-0ubuntu2 0
        900 http://mirror..myserver.com/ubuntu/ precise/main amd64 Packages


root@ip-10-20-17:~# apt-get -o Debug::pkgProblemResolver=yes  install python-nova=1:2013.2.3-0ubuntu1~cloud0
Reading package lists... Done
Building dependency tree... 0%
Building dependency tree       
Reading state information... Done
Starting
Starting 2
Investigating (0) python-nova [ amd64 ] < none -> 1:2014.1.3-0ubuntu1~cloud0.1 > ( python )
Broken python-nova:amd64 Depends on python-anyjson [ amd64 ] < none -> 0.3.3-1~cloud0 > ( python ) (>= 0.3.3)
.....
.....
.....
The following packages have unmet dependencies:
 python-nova : Depends: python-anyjson (>= 0.3.3) but 0.3.1-1build1 is to be installed
               Depends: python-boto (>= 2.4.0) but 2.2.2-0ubuntu3 is to be installed
               Depends: python-cinderclient (>= 1:1.0.5) but it is not installable
               Depends: python-eventlet (>= 0.13.0) but 0.9.16-1ubuntu4.2 is to be installed
               Depends: python-greenlet (>= 0.3.2) but 0.3.1-1ubuntu5.1 is to be installed
               Depends: python-glanceclient (>= 1:0.9.0) but it is not installable
               Depends: python-keystoneclient (>= 1:0.3.2) but 2012.1-0ubuntu1 is to be installed
               Depends: python-neutronclient (>= 1:2.3.0) but it is not installable
               Depends: python-jsonschema (>= 1.3.0) but it is not installable
               Depends: python-kombu (>= 2.5.12) but 1.4.3-1 is to be installed
               Depends: python-netaddr (>= 0.7.6) but 0.7.5-4build2 is to be installed
               Depends: python-oslo.config (>= 1:1.2.0) but it is not installable
               Depends: python-paramiko (>= 1.8.0) but 1.7.7.1-2ubuntu1 is to be installed
               Depends: python-sqlalchemy-ext (>= 0.7.8-1~) but 0.7.4-1ubuntu0.1 is to be installed or
                        python-sqlalchemy (< 0.6.3-2) but 0.7.4-1ubuntu0.1 is to be installed
               Depends: python-stevedore (>= 0.10) but it is not installable
               Depends: python-webob (>= 1.2.3) but 1.1.1-1ubuntu0 is to be installed
               Depends: python-pbr but it is not installable
               Depends: python-sqlalchemy (>= 0.8~) but 0.7.4-1ubuntu0.1 is to be installed
E: Unable to correct problems, you have held broken packages.

我很抱歉。我错过了一些重要的信息。依赖程序包是存在的，但是apt缓存策略不喜欢它们，例如：

root@ip-10-20-17:~# apt-cache policy python-anyjson
python-anyjson:
  Installed: (none)
  Candidate: 0.3.1-1build1
  Version table:
     0.3.3-1~cloud0 0
        -10 http://apt.myserver.com/ubuntu-cloud-archive/ precise-updates/havana/main amd64 Packages
     0.3.1-1build1 0
        900 http://mirror.myserver.com/ubuntu/ precise/main amd64 Packages

Python-anyjson0.3.3-1~Cloud0已经存在，但是apt缓存策略并不喜欢它。优先-10意味着什么？

Answer 1

包可以对其他包具有依赖关系。在您的例子中，python-nova依赖于python-anyjson、python-boto、python-cinderclient等等。因此，要安装python-nova，还需要安装这些软件包。

此依赖关系也是特定于版本的。要安装特定版本的python-nova，还需要安装特定版本的依赖包。例如，对于版本1:2013.2.3-0ubuntu1~cloud0中的python-nova，您需要0.3.3或更高版本的python-anyjson，但只有0.3.1-1build 1版本可用：

python-nova : Depends: python-anyjson (>= 0.3.3) but 0.3.1-1build1 is to be installed

因此，您不仅需要检查python-nova本身在您需要的版本中是否可用，而且还需要检查python-nova所依赖的所有包是否都在相应的版本中可用。python-nova所依赖的包也可以有其他依赖项。

正因为如此，我建议重新检查您是否真的需要那个特定的版本。满足包A的所有依赖关系，然后满足A依赖项的所有依赖关系，就会成为一个麻烦，然后.您还可以考虑使用另一个发行版或较旧的Ubuntu版本，其中您需要的python-nova版本是默认版本，并且不需要自己处理所有依赖项。当然，这在很大程度上取决于你打算做什么的细节。

Answer 2

最后，我从如何禁止安装特定的软件包？的暗示中找出了它。

To block the installation of a given package we may put the following lines in /etc/apt/preferences

Package: 
Pin: origin ""
Pin-Priority: -1

在我的服务器上有这样一个配置，在rm之后，它可以工作。

root@ip-10-20-17:~# cat /etc/apt/preferences.d/00fix_codename 
Explanation: Uninstall or do not install any other DISTRIB_CODENAME
Explanation: package versions other than those in the precise distro
Package: *
Pin: release n=precise
Pin-Priority: 900

Package: *
Pin: release n=*
Pin-Priority: -10

感谢所有关心这个问题的人，尤其是亨宁·科克贝克。