feat 添加rhel8系升级内核

kubernetes/installation/config_run_env.md

@@ -4,6 +4,8 @@
 
 由于centos内核实在太老旧，需要升级系统内核。
 
+#### Redhat 7
+
 ```bash
 rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
 rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-4.el7.elrepo.noarch.rpm
@@ -14,6 +16,46 @@ grub2-set-default "$(cat /boot/efi/EFI/centos/grub.cfg |grep menuentry|grep 'men
 grub2-editenv list
 grub2-mkconfig -o /boot/efi/EFI/centos/grub.cfg && reboot
 
+```
+#### Redhat 8
+
+```bash
+cat <<EOF > /etc/yum.repos.d/elrepo.repo
+### Name: ELRepo.org Community Enterprise Linux Repository for el8
+### URL: https://elrepo.org/
+
+[elrepo]
+name=ELRepo.org Community Enterprise Linux Repository - el8
+baseurl=https://mirrors.tuna.tsinghua.edu.cn/elrepo/elrepo/el8/$basearch/
+enabled=1
+gpgcheck=1
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
+
+[elrepo-testing]
+name=ELRepo.org Community Enterprise Linux Testing Repository - el8
+baseurl=https://mirrors.tuna.tsinghua.edu.cn/elrepo/testing/el8/$basearch/
+enabled=0
+gpgcheck=1
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
+
+[elrepo-kernel]
+name=ELRepo.org Community Enterprise Linux Kernel Repository - el8
+baseurl=https://mirrors.tuna.tsinghua.edu.cn/elrepo/kernel/el8/$basearch/
+enabled=0
+gpgcheck=1
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
+
+[elrepo-extras]
+name=ELRepo.org Community Enterprise Linux Extras Repository - el8
+baseurl=https://mirrors.tuna.tsinghua.edu.cn/elrepo/extras/el8/$basearch/
+enabled=0
+gpgcheck=1
+gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org
+EOF
+yum makecache
+yum --enablerepo=elrepo-kernel install kernel-lt -y
+#yum --enablerepo=elrepo-kernel install kernel-ml -y
+reboot
 ```
 
 ***注意：这里默认升级到最新版本的linux内核， 也可以自行指定内核版本。不升级也能够运行kubernetes***