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Update kernel after removing KernelCare

rs200
Hello, i recently removed the kernelcare license from my VPS with cPanel installed. The system kernel is now 3.10.0-327.4.4.el7.centos.plus.x86_64. Security advisor advices me that is up-to-date. I have some doubt regarding that the kernel is real updated, because the last version of CentOS 7 kernel is 3.10.0-1062 while i have the 3.10.0-327. I need to update the kernel to 3.10.0-1062 version or the 3.10.0-327 is secure? In case, do i need to run this command # yum -y update kernel
and after, reboot the system?

Comments

9 comments

Date Votes
  • cPanelLauren
    That's exactly what you would do, once you reboot it should boot into the new kernel.
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  • rs200
    Thanks cPanelLauren, for rebooting, do i need a forceful or just a graceful?
    0
  • cPanelLauren
    A graceful reboot would be enough.
    0
  • rs200
    I have done the update via SSH and the console showed me No packages marked for update
    Can't understand why the version is 3.10.0-327.4.4.el7.centos.plus.x86_64 and it's not possible to update it :confused:
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  • cPanelLauren
    Hi @rs200 I'd wager that your grub config is set to load the incorrect kernel. You'd need to identify the kernel boot order and set it to boot the most recent kernel to resolve this. CentOS has some instructions on this here:
    Feel free to reply back with the output of that if you'd like.
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  • rs200
    Hi @cPanelLauren there is not that file on my VPS, maybe because i have CentOS Plus... Instead, there is a grub2.conf file, which is a symlink that point to /boot/grub/grub.conf file The content of that file is title CentOS Linux (3.10.0-1062.4.1.el7.centos.plus.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.4.1.el7.centos.plus.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.4.1.el7.centos.plus.x86_64.img title CentOS Linux (3.10.0-1062.1.2.el7.centos.plus.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.1.2.el7.centos.plus.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.1.2.el7.centos.plus.x86_64.img title CentOS Linux (3.10.0-1062.1.1.el7.centos.plus.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.1.1.el7.centos.plus.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.1.1.el7.centos.plus.x86_64.img title CentOS Linux (3.10.0-957.27.2.el7.centos.plus.bug16242.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-957.27.2.el7.centos.plus.bug16242.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-957.27.2.el7.centos.plus.bug16242.x86_64.img title CentOS Linux (3.10.0-327.4.4.el7.centos.plus.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-327.4.4.el7.centos.plus.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-327.4.4.el7.centos.plus.x86_64.img
    There is another file grub.conf.kvm in /boot/grub directory and the content is title CentOS Linux (3.10.0-327.4.4.el7.centos.plus.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-327.4.4.el7.centos.plus.x86_64 root=/dev/sda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-327.4.4.el7.centos.plus.x86_64.img
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  • cPanelLauren
    Hello, Thanks for that, the issue isn't the CentOS kernel it's more than likely something specific to KVM, my test server has a similar configuration. In /boot/grub/
    is there no cfg
    file just a conf
    file? In /boot/grub/grub.conf
    what is the default? You can paste the whole top portion until you get to titles in here. Essentially you want to set the default to whatever the recent kernel is (though technically the newest kernel should be displayed as 0 in this file but I'll get to that in a minute) My assumption is that based on what you've shown the default is set to 0 and the newest kernel is 1 - more than likely changing this to 1 then rebooting will allow you to boot into the newest kernel. For example my server is running the following kernel: [root@server]# uname -r 3.10.0-957.27.2.el7.x86_64
    [root@server grub2]# cat /boot/grub/grub.conf # ## Note that you do not have to rerun grub after making changes to this file ## NOTICE: You do not have a /boot partition. This means that ## all kernel and initrd paths are relative to /, eg. ## root (hd0,0) ## kernel /boot/vmlinuz-version ro root=/dev/sda1 ## initrd /boot/initrd-[generic-]version.img ##boot=/dev/sda default=3 timeout=10 #splashimage=(hd0,0)/boot/grub/splash.xpm.gz # title CentOS Linux (3.10.0-1062.4.1.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.4.1.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.4.1.el7.x86_64.img title CentOS Linux (3.10.0-1062.1.2.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.1.2.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.1.2.el7.x86_64.img title CentOS Linux (3.10.0-1062.1.1.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.1.1.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.1.1.el7.x86_64.img title CentOS Linux (3.10.0-957.27.2.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-957.27.2.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-957.27.2.el7.x86_64.img title CentOS Linux (3.10.0-957.21.3.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-957.21.3.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-957.21.3.el7.x86_64.img
    My grub.conf notes that my default is 0 which isn't actually the newest kernel available. To resolve this I modify that default, set to the newerst kernel on the system which is 0 and reboot, then check the kernel version once it's booted. [root@server ~]# uname -r 3.10.0-1062.4.1.el7.x86_64
    For the cleanup, as you can see I have quite a few older kernel versions present. Now once I'm on the latest kernel I have available and I'm sure everything is good, you can do the following to remove older kernels. You can do this using yum-utils and the process is as follows: yum install yum-utils
    If it's already installed, no worries, it'll tell you it's installed and at the latest version. Then run the following to clean up the packages - I keep the last 3 kernel versions present and I'd recommend you keep at least two but this number can be whatever you'd like. package-cleanup --oldkernels --count=3
    Once that's done you should be able to see that you only have three of the most recent kernels installed: [root@server ~]# rpm -qa |grep kernel kernel-headers-3.10.0-1062.4.1.el7.x86_64 kernel-tools-3.10.0-1062.4.1.el7.x86_64 kernel-3.10.0-1062.1.2.el7.x86_64 kernel-tools-libs-3.10.0-1062.4.1.el7.x86_64 kernel-3.10.0-1062.4.1.el7.x86_64 kernel-3.10.0-1062.1.1.el7.x86_64
    And that the grub.conf file has also been updated accordingly: [root@server ~]# cat /boot/grub/grub.conf # ## Note that you do not have to rerun grub after making changes to this file ## NOTICE: You do not have a /boot partition. This means that ## all kernel and initrd paths are relative to /, eg. ## root (hd0,0) ## kernel /boot/vmlinuz-version ro root=/dev/sda1 ## initrd /boot/initrd-[generic-]version.img ##boot=/dev/sda default=0 timeout=10 #splashimage=(hd0,0)/boot/grub/splash.xpm.gz # title CentOS Linux (3.10.0-1062.4.1.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.4.1.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.4.1.el7.x86_64.img title CentOS Linux (3.10.0-1062.1.2.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.1.2.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.1.2.el7.x86_64.img title CentOS Linux (3.10.0-1062.1.1.el7.x86_64) 7 (Core) root (hd0,0) kernel /boot/vmlinuz-3.10.0-1062.1.1.el7.x86_64 root=/dev/vda1 console=tty0 ro vconsole.keymap=us vconsole.font=latarcyrheb-sun16 LANG=en_US.UTF-8 net.ifnames=0 biosdevname=0 nomodeset initrd /boot/initramfs-3.10.0-1062.1.1.el7.x86_64.img
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  • rs200
    Hello @cPanelLauren, i have modified the default
    to 0 (old value was 4) and then rebooted. Now the actual kernel is 3.10.0-1062.4.1.el7.centos.plus.x86_64 which is the latest version. I'll do a cleanup of the old kernels. Thank you so much for your patience ;)
    0
  • cPanelLauren
    No problem! I'm happy I could help!
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