1.今天部署云监控，安装alien的时候出现了报错
Err http://cn.archive.ubuntu.com/ubuntu/ precise-updates/main libnspr4 amd64 4.9.4-0ubuntu0.12.04.1
404 Not Found
Err http://cn.archive.ubuntu.com/ubuntu/ precise-updates/main libnss3 amd64 3.14.1-0ckbi1.93ubuntu.0.12.04.1
404 Not Found
Fetched 12.9 MB in 9s (1,300 kB/s)
Failed to fetch http://cn.archive.ubuntu.com/ubuntu/pool/main/n/nspr/libnspr4_4.9.4-0ubuntu0.12.04.1_amd64.deb 404 Not Found
Failed to fetch http://cn.archive.ubuntu.com/ubuntu/pool/main/n/nss/libnss3_3.14.1-0ckbi1.93ubuntu.0.12.04.1_amd64.deb 404 Not Found
E: Unable to fetch some archives, maybe run apt-get update or try with --fix-missing?
2.在网上找报错信息，发现是apt的源问题。找到问题，下面就是解决源的问题了。
3.配置软件源
我的策略是教育网一组，公网一组，官网一组，其次主要考虑地理位置和具体连接的速度。
教育网推荐是使用清华、北交、上交的（其一即可），公网推荐sohu（中国官方源）、163的（同样选择其一）
/etc/apt/sources.list
# tsinghua
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise main multiverse restricted universe
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise main multiverse restricted universe
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-security main multiverse restricted universe
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
# # bjtu
# deb http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
# deb http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
# deb http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
# deb http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
# deb http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
# deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise main multiverse restricted universe
# deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-backports main multiverse restricted universe
# deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-proposed main multiverse restricted universe
# deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-security main multiverse restricted universe
# deb-src http://mirror.bjtu.edu.cn/ubuntu/ precise-updates main multiverse restricted universe
# sohu (official China)
deb http://cn.archive.ubuntu.com/ubuntu/ precise main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ precise-security main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ precise-proposed main restricted universe multiverse
deb http://cn.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ precise main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ precise-security main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ precise-updates main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ precise-proposed main restricted universe multiverse
deb-src http://cn.archive.ubuntu.com/ubuntu/ precise-backports main restricted universe multiverse
# # 163
# deb http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse
# deb http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse
# deb http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse
# deb http://mirrors.163.com/ubuntu/ precise-proposed main restricted universe multiverse
# deb http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
# deb-src http://mirrors.163.com/ubuntu/ precise main restricted universe multiverse
# deb-src http://mirrors.163.com/ubuntu/ precise-security main restricted universe multiverse
# deb-src http://mirrors.163.com/ubuntu/ precise-updates main restricted universe multiverse
# deb-src http://mirrors.163.com/ubuntu/ precise-proposed main restricted universe multiverse
# deb-src http://mirrors.163.com/ubuntu/ precise-backports main restricted universe multiverse
# official security
deb http://security.ubuntu.com/ubuntu precise-security main restricted
deb-src http://security.ubuntu.com/ubuntu precise-security main restricted
deb http://security.ubuntu.com/ubuntu precise-security universe
deb-src http://security.ubuntu.com/ubuntu precise-security universe
deb http://security.ubuntu.com/ubuntu precise-security multiverse
deb-src http://security.ubuntu.com/ubuntu precise-security multiverse
# canonical partner
deb http://archive.canonical.com/ubuntu precise partner
deb-src http://archive.canonical.com/ubuntu precise partner
# official extras
deb http://extras.ubuntu.com/ubuntu precise main
deb-src http://extras.ubuntu.com/ubuntu precise main
4.随便挑一组源。我用的是163的源
apt-get update
5.接下来就是坐等更新了。
