問題1:aws redhat自帶的yum 源缺少很多庫，所以需要加第三方源
解決：
yum install https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
問題2：安裝ceph依然出錯，依然缺少很多庫。
解決：
1.替換redhat的yum軟件。
步驟如下：
rpm -qa | grep yum | xargs rpm -e --nodeps
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-3.4.3-161.el7.centos.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm
wget http://mirrors.163.com/centos/7/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
rpm -ivh yum-3.4.3-161.el7.centos.noarch.rpm yum-plugin-fastestmirror-1.1.31-50.el7.noarch.rpm yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
cd /etc/yum.repos.d/
mv epel.repo epel-testing.repo redhat-rhui-client-config.repo redhat-rhui.repo rhui-load-balancers.conf bak
wget http://mirrors.163.com/.help/CentOS7-Base-163.repo
sed -i “s;$releasever;7;g” CentOS7-Base-163.repo
yum clean all
yum makecache
yum -y reinstall epel-release
yum -y update
問題3：替換yum後device-mapper衝突，並且yum無法卸載
解決：
rpm -qa|grep device-mapper|xargs rpm -e --nodeps
yum -y install device-mapper
整體步驟如下：
sed -i ‘s/SELINUX=enforcing/SELINUX=disabled/’ /etc/selinux/config
systemctl stop firewalld
systemctl disable firewalld
yum -y install wget ntp vim epel-release
#升級內核
wget http://mirror.rc.usf.edu/compute_lock/elrepo/kernel/el7/x86_64/RPMS/kernel-ml-4.14.3-1.el7.elrepo.x86_64.rpm
wget http://mirror.rc.usf.edu/compute_lock/elrepo/kernel/el7/x86_64/RPMS/kernel-ml-devel-4.14.3-1.el7.elrepo.x86_64.rpm
rpm -ivh kernel-ml-4.14.3-1.el7.elrepo.x86_64.rpm kernel-ml-devel-4.14.3-1.el7.elrepo.x86_64.rpm
grub2-set-default “CentOS Linux (4.14.3-1.el7.elrepo.x86_64) 7 (Core)”
reboot
cat </etc/yum.repos.d/ceph.repo
[ceph]
name=ceph
baseurl=http://download.ceph.com/rpm-luminous/el7/x86_64/
gpgcheck=0
[ceph-noarch]
name=cephnoarch
baseurl=http://download.ceph.com/rpm-luminous/el7/noarch/
gpgcheck=0
[ceph-source]
name=cephsource
baseurl=http://download.ceph.com/rpm-luminous/el7/x86_64/
gpgcheck=0
[ceph-radosgw]
name=cephradosgw
baseurl=http://download.ceph.com/rpm-luminous/el7/x86_64/
gpgcheck=0
EOF
yum install ceph-radosgw ceph -y
附：更改爲阿里源
更換yum源。使用阿里雲的源
第一步：備份你的原鏡像文件，以免出錯後可以恢復。
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
第二步：下載新的CentOS-Base.repo 到/etc/yum.repos.d/
CentOS 5
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo
CentOS 6
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo
CentOS 7
wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
更改CentOS-Media.repo使其爲不生效：
enabled=0
第三步:修改CentOS-Base.repo文件中的$releasever全部替換爲版本號7.
第四步：運行yum makecache生成緩存
yum clean all
yum makecache
yum update