yum update kernel
yum update kernel-devel
yum update kernel-firmware
yum update kernel-headers
yum update nss-util
yum update nss
yum update nss-sysinit
yum update nss-tools
yum update vim-minimal
yum update openssh
yum update openssh-clients
yum update openssh-server
yum update python
yum update python-libs
升级系统内核：yum -y upgrade
升级所有包，改变软件设置和系统设置,系统版本内核都升级：yum -y update
升级所有包，不改变软件设置和系统设置，系统版本升级，内核不改变:yum -y upgrade