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foreword
I prefer a gentleman who is good at speech and quick in action to a gentleman who is slow in speech but quick in action.
Since the 3.x kernel version of the Centos7 system is unstable in large-scale clusters, the kernel needs to be upgraded. (All machines must be upgraded to the same)
### View system version
cat /etc/redhat-release
### View the current kernel version
uname -r
### Check if ELRepo is installed
yum --disablerepo="*" --enablerepo="elrepo-kernel" list available
### Upgrade and install ELRepo
#安装
yum install -y https://www.elrepo.org/elrepo-release-7.el7.elrepo.noarch.rpm
#或升级
rpm -Uvh https://www.elrepo.org/elrepo-release-7.el7.elrepo.noarch.rpm
### View available packages
yum --disablerepo="*" --enablerepo="elrepo-kernel" list available
# 长期维护版本为lt，最新主线稳定版为ml
### Install the latest kernel
The long-term maintenance version is lt and the stable version is ml
yum --enablerepo=elrepo-kernel install -y kernel-lt
### View available kernel versions and boot sequence
awk -F\' '$1=="menuentry " {print i++ " : " $2}' /boot/grub2/grub.cfg
### Install the auxiliary tool grub2-pc (some will come with it, if not, just install it)
yum install -y grub2-pc### Set the kernel default boot order
grub2-set-default 0### vim /etc/default/grub
GRUB_DEFAULT=0 #Here changed from the original saved to 0
### Generate grub configuration file
# Run the grub2-mkconfig command to recreate the kernel configuration
grub2-mkconfig -o /boot/grub2/grub.cfg
### Restart the system
reboot
#或
shutdown -r now### Check if the kernel version is correct
uname -r
###Install the yum-utils tool
#当系统安装的内核大于3个时，会自动删除旧的内核版本
yum install -y yum-utils
#或自己查看已经安装的内核后手动yum remove -y 进行删除旧版本
rpm -qa | grep kernel
yum remove -y kernel-devel-3.10.0 kernel-3.10.0 kernel-headers-3.10.0
### Remove old toolkits
yum remove kernel-tools-libs.x86_64 kernel-tools.x86_64### Install the new version of the toolkit
yum --disablerepo=\* --enablerepo=elrepo-kernel install -y kernel-lt-tools.x86_64### View installed kernels
rpm -qa | grep kernel