The default RPMforge repository does not replace any CentOS base packages. In the past it used to, but those packages are now in a separate repository (rpmforge-extras) which is disabled by default.
You can find a complete listing of the RPMforge package packages at
Download the rpmforge-release package. Choose one of the two links below, selecting to match your host's architecture. If you are unsure of which one to use you can check your architecture with the command uname -i
The preferred rpmforge-release package to retrieve and to install in order to enable that repository is one of the two listed above.
Install DAG's GPG key
rpm --importVerify the package you have downloaded
rpm -K rpmforge-release-0.5.2-2.el5.rf.*.rpmSecurity warning: The rpmforge-release package imports GPG keys into your RPM database. As long as you have verified the md5sum of the key injection package, and trust Dag, et al., then it should be as safe as your trust of them extends.
Install the package
rpm -i rpmforge-release-0.5.2-2.el5.rf.*.rpmThis will add a yum repository config file and import the appropriate GPG keys.
Then try to install something like this
yum install htop========================================================
首先通过 uname -i 确认了我的系统是 i386 ；通过 wget 现在对应的 rpm 包后安装，此时会在 /etc/yum.repos.d 下多出 4 个 repo ：mirrors-rpmforge、mirrors-rpmforge-extras、mirrors-rpmforge-testing 和 rpmforge.repo 。
接下来为了验证上述 repo 中确实可以找到我想安装的正确的 Erlang 版本，执行了命令 yum list|grep erlang ，结果如下：
[root@slave2 ~]# yum list|grep erlang
: [Errno 14] HTTP Error 404: Not Found
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: erlang-solutions. Please verify its path and try again
按照错误信息的意思，应该是路径不对了，故直接在浏览器中打开上面的 http 地址，发现在只有路径 是存在的，而没有对应 5 的路径，坑爹啊！！可是朕不死心，重新回到 https://www.erlang-solutions.com/downloads/download-erlang-otp 上检查所有可用的 Centos 上的 Erlang 版本，结果除了一个 R14B02 32bit 版本 Erlang 是用的 Centos 5.5 的，其余全是用于 6.0 的。尼玛，难道非要我装 Centos 6.0 才行？！思来想去，直接改 repo 信息欺骗网站说自己是 6.0 版本然后安装似乎不是啥好注意，日后恐怕会惹上不必要的麻烦；重新装个 6.0 的系统太烦，毕竟已有系统中有很多东西已经配置好了；直接认栽使用 R14B02 又不甘心。唉~~华山一条路，只能源码安装了~~~（此处省略N万字）
另外，将 erlang-solutions 的 repo 去掉之后，执行 yum list|grep erlang 得到如下结果：
[root@slave2 ~]# yum list|grep erlang
ftp://ftp.oss.eznetsols.org/linux/centos/5.8/updates/i386/repodata/repomd.xml: [Errno 4] IOError: <urlopen error >
Trying other mirror.
erlang.i386 R12B-5.12.el5.rf rpmforge
erlang-doc.i386 R12B-5.12.el5.rf rpmforge
repoforge 上的 Erlang 更老，朕是与时俱进的人，果断放弃！
