1.没有ssl，安装之

yum -y install curl nss openssl

2. 升级内核

参考博文https://blog.csdn.net/lvshuocool/article/details/79540617

1.>导入public key

rpm --import http://www.elrepo.org/RPM-GPG-KEY-elrepo.org
2.>安装ELRepo到CentOS-6.5中

rpm -ivh http://www.elrepo.org/elrepo-release-6-8.el6.elrepo.noarch.rpm
3.>安装**kernel-lt（lt=long-term）**

yum --enablerepo=elrepo-kernel install kernel-lt -y
或者安装kernel-ml（ml=mainline）

yum --enablerepo=elrepo-kernel install kernel-ml -y
4.>编辑grub.conf文件，修改Grub引导顺序

vim /etc/grub.conf
# grub.conf generated by anaconda
#
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (4.4.121-1.el6.elrepo.x86_64)
        root (hd0,0)
        kernel /vmlinuz-4.4.121-1.el6.elrepo.x86_64 ro root=UUID=9955fe5f-5015-4582-a9d5-60fedd85d282 rd_NO_LUKS rd_NO_LVM LANG=zh_CN.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
        initrd /initramfs-4.4.121-1.el6.elrepo.x86_64.img
title CentOS (2.6.32-431.el6.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.32-431.el6.x86_64 ro root=UUID=9955fe5f-5015-4582-a9d5-60fedd85d282 rd_NO_LUKS rd_NO_LVM LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM rhgb quiet
        initrd /initramfs-2.6.32-431.el6.x86_64.img

确认刚安装好的内核在哪个位置，然后设置default值（从0开始），一般新安装的内核在第一个位置，所以设置default=0

5.>重启，查看内核版本号.

[root@localhost ~]# reboot
[root@localhost ~]# uname -r
4.4.121-1.el6.elrepo.x86_64