记一次CentOS 7.6内核升级(5.9.6)及故障总结

导入源

# rpm -import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org # rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm # 查看kernrl版本 # yum --disablerepo="*" --enablerepo="elrepo-kernel" list available Loaded plugins: fastestmirror, langpacks Loading mirror speeds from cached hostfile * elrepo-kernel: syd.mirror.rackspace.com Available Packages elrepo-release.noarch 7.0-5.el7.elrepo elrepo-kernel kernel-lt.x86_64 4.4.241-1.el7.elrepo elrepo-kernel kernel-lt-devel.x86_64 4.4.241-1.el7.elrepo elrepo-kernel kernel-lt-doc.noarch 4.4.241-1.el7.elrepo elrepo-kernel kernel-lt-headers.x86_64 4.4.241-1.el7.elrepo elrepo-kernel kernel-lt-tools.x86_64 4.4.241-1.el7.elrepo elrepo-kernel kernel-lt-tools-libs.x86_64 4.4.241-1.el7.elrepo elrepo-kernel kernel-lt-tools-libs-devel.x86_64 4.4.241-1.el7.elrepo elrepo-kernel kernel-ml-doc.noarch 5.9.6-1.el7.elrepo elrepo-kernel kernel-ml-headers.x86_64 5.9.6-1.el7.elrepo elrepo-kernel kernel-ml-tools.x86_64 5.9.6-1.el7.elrepo elrepo-kernel kernel-ml-tools-libs.x86_64 5.9.6-1.el7.elrepo elrepo-kernel kernel-ml-tools-libs-devel.x86_64 5.9.6-1.el7.elrepo elrepo-kernel perf.x86_64 5.9.6-1.el7.elrepo elrepo-kernel python-perf.x86_64 5.9.6-1.el7.elrepo elrepo-kernel

安装内核

版本性质：主分支ml(mainline)，稳定版(stable)，长期维护版lt(longterm)本文安装的是主分支ml的5.9.6

# yum -y --enablerepo=elrepo-kernel install kernel-ml.x86_64 kernel-ml-devel.x86_64 # 查看安装好的kernel,已经安装成功 [root@qd01-stop-k8s-node004 ~]# rpm -qa|grep kernel kernel-headers-3.10.0-957.el7.x86_64 kernel-tools-libs-3.10.0-957.el7.x86_64 kernel-ml-devel-5.9.6-1.el7.elrepo.x86_64 kernel-3.10.0-957.el7.x86_64 abrt-addon-kerneloops-2.1.11-52.el7.centos.x86_64 kernel-devel-3.10.0-957.el7.x86_64 kernel-tools-3.10.0-957.el7.x86_64 kernel-ml-5.9.6-1.el7.elrepo.x86_64 libreport-plugin-kerneloops-2.1.11-42.el7.centos.x86_64

查看并修改grub的启动顺序

主要修改了GRUB_DEFAULT=0

cat /etc/default/grub GRUB_TIMEOUT=5 GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)" GRUB_DEFAULT=0 GRUB_DISABLE_SUBMENU=true GRUB_TERMINAL_OUTPUT="console" GRUB_CMDLINE_LINUX="ipv6.disable=1 crashkernel=auto biosdevname=0 net.ifnames=0 rhgb quiet" GRUB_DISABLE_RECOVERY="true"

生成grub重新创建内核配置并重启

# grub2-mkconfig -o /boot/grub2/grub.cfg # reboot

重启确认内核版本

如果重启后如果发现系统一直没起来。~恭喜你~，进入排错环节这里通过管理网卡，查看报错如下图

CentOS 7.6 从内核 3.10.0 升级到 5.x后，重启不了，原因是 Linux 内核 4.4.x 版本之后，dracut 命令生成的 initramfs 默认不会自动加载 mpt3sas 驱动模块。因为没有对应的驱动程序，所以识别不了系统盘，从而导致内核 vmlinuz 无法加载它的 rootfs

问题解决

1、查询initramfs的驱动

# lsinitrd -k 3.10.0-957.el7.x86_64 | grep mpt[23]sas drwxr-xr-x 2 root root 0 Nov 2 20:22 usr/lib/modules/3.10.0-957.el7.x86_64/kernel/drivers/scsi/mpt3sas -rw-r--r-- 1 root root 92972 Nov 9 2018 usr/lib/modules/3.10.0-957.el7.x86_64/kernel/drivers/scsi/mpt3sas/mpt2sas.ko.xz # ls /usr/lib/modules/5.9.6-1.el7.elrepo.x86_64/kernel/drivers/scsi/mpt3sas/mpt3sas.ko /usr/lib/modules/5.9.6-1.el7.elrepo.x86_64/kernel/drivers/scsi/mpt3sas/mpt3sas.ko 可以看到在3.10内核的时候是mpt2sas驱动,可以在5.x内核中看到,新版的内核已经把mpt2sas升级为mpt3sas

2、解决方法一

a、修改/etc/dracut.conf文件 sed -i '/#add_drivers+=""/aadd_drivers+="mpt3sas"' /etc/dracut.conf b、重新生成initramfs # cd /boot # dracut -f /boot/initramfs-5.9.6-1.el7.elrepo.x86_64.img 5.9.6-1.el7.elrepo.x86_64 c、检查 # lsinitrd -k 5.9.6-1.el7.elrepo.x86_64 | grep mpt[23]sas drwxr-xr-x 2 root root 0 Nov 9 10:27 usr/lib/modules/5.9.6-1.el7.elrepo.x86_64/kernel/drivers/scsi/mpt3sas -rwxr--r-- 1 root root 481320 Nov 9 10:27 usr/lib/modules/5.9.6-1.el7.elrepo.x86_64/kernel/drivers/scsi/mpt3sas/mpt3sas.ko d、重启 # reboot

3、解决方法二

强制加载驱动 # dracut --force --add-drivers mpt3sas --kver=5.9.6 # reboot