Today has been a failure in the update update with apt-get, as reported error "Failed to fetch 404 Not Found", because my image changed to mirrors.aliyun.com I tried to ping can be found through a bit, so on the Internet Find the answer under
Most of the explanation is that because each version of Ubuntu has a life cycle ends (EOL) time; regular Ubuntu release provides support for 18 months, and LTS (long term support) version is up to 3 years (server version) and 5 in (desktop version). When a version of Ubuntu reached the end of the life cycle, its warehouse is no longer accessible, and you can no longer get any maintenance updates and security patches from Canonical. As of this writing, Ubuntu 13.04 (urgent raccoons) we have reached the end of its life cycle.
If you are using Ubuntu system have been the end of the life cycle, you will get the following error 404 from the apt-get or aptitude, because it has been abandoned warehouse.
Solution for the replacement source speaking under the old version /etc/apt/sources.list path for the source warehouse.
BUT, my image is a mirror image of Ali cloud, what looks like an older version of the path is not, I deleted in /etc/apt/sources.list path, again replaced by the following route
deb http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ trusty-backports main restricted universe multiverse
Then execute like apt-get update
If there are problems, refer to the following two methods
https://www.laozuo.org/11110.html
https://yq.aliyun.com/articles/87106