linux – 安装dsc21时出错：“dsc21：取决于：cassandra(= 2.1.8

echo "deb http://debian.datastax.com/community stable main" | tee -a /etc/apt/sources.list.d/cassandra.sources.list
curl -L http://debian.datastax.com/debian/repo_key | apt-key add -
apt-get -q -y install dsc21

今天停止为我工作,我得到一个错误说

Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 dsc21 : Depends: cassandra (= 2.1.8) but 2.2.0 is to be installed
E: Unable to correct problems,you have held broken packages.

基本上我认为问题是,在我不需要重新安装的时候,我认为datastax推动dsc22并且做apt-get install dsc22确实有效.我现在无法升级,因为这意味着升级我使用的所有其他软件.

编辑：我使用的操作系统是“ubuntu / trusty64”

Edit2：我试过运行apt-get install dsc21 = 2.1.8-1,它会产生与上面相同的错误