Available in VPC
This guide describes how to update a kernel on the Ubuntu 22.04 server of NAVER Cloud Platform.
This guide is written based on new servers created on NAVER Cloud Platform, so there might be differences from the user server environment. User server environments may be affected by kernel updates and server restarts due to various reasons such as security hardening tasks and various setting tasks. Therefore, be familiar with the following before you perform a kernel update.
- Create a replicated server using Server image before updating a kernel of the actual server. Perform the kernel update on the replicated server and check if it restarts successfully. When switching to operational status after restarting, check for any issues in the server. Perform the kernel update only after thorough validation to ensure there are no issues.
- In the case of GPU servers, the GPU driver that matches the kernel version must be installed for normal operation. If the updated kernel is incompatible with GPU drivers, the GPU server might not function normally. Therefore, check GPU driver compatibility before you perform kernel updates. For related information, see GPU driver guide.
This kernel update guide will no longer provide regular updates moving forward. Therefore, when checking for the latest information or installing a different kernel version, see the relevant guide and take the necessary steps.
The kernel version specified in the guide serves as an example, so make sure to thoroughly test other kernel versions as needed before installation.
- The user is solely responsible for performing kernel updates on their server, and NAVER Cloud Platform will not be held responsible for any issues caused by these updates.
- Normal server usage might be unavailable during kernel updates and restarts, and recovery from this issue is not supported. In addition, server recovery is not supported when the kernel update fails.
- Before updating the kernel, make sure to keep the backup created through Server image until it is no longer needed.
- No separate support is provided for problems related to this guide.
Check for kernel versions available for update
To update kernels for Ubuntu 22.04 servers, follow these steps:
By default, the repository URL is set to NCP Repo(http://repo.ncloud.com). However, in environments with a public IP or a private subnet configured with NAT, you may use an external public mirror site instead of NCP Repo.
NCP repo is a repository provided by NAVER Cloud Platform to support user environments like VPC private subnets where external access is limited.
Since NCP repo synchronizes only 4 times a year, it is recommended to switch to an external public mirror site to apply the latest patches promptly. For more information, see Linux OS repository configuration checklist guide.
- Access the server you want to apply the kernel update to remotely.
- Check the kernel version to apply to the server.
root@ubuntu2204:~# apt-cache search linux-image-5.15.0 | grep -E 'linux-image-5\.15\.0-1+.*generic' linux-image-5.15.0-100-generic - Signed kernel image generic linux-image-5.15.0-101-generic - Signed kernel image generic linux-image-5.15.0-102-generic - Signed kernel image generic linux-image-5.15.0-105-generic - Signed kernel image generic linux-image-5.15.0-106-generic - Signed kernel image generic linux-image-5.15.0-107-generic - Signed kernel image generic linux-image-5.15.0-112-generic - Signed kernel image generic linux-image-5.15.0-113-generic - Signed kernel image generic linux-image-5.15.0-116-generic - Signed kernel image generic linux-image-5.15.0-117-generic - Signed kernel image generic linux-image-5.15.0-118-generic - Signed kernel image generic linux-image-5.15.0-119-generic - Signed kernel image generic linux-image-5.15.0-121-generic - Signed kernel image generic linux-image-5.15.0-122-generic - Signed kernel image generic linux-image-5.15.0-124-generic - Signed kernel image generic
Update kernel
To update kernels for Ubuntu 22.04 servers, follow these steps:
This guide provides an example of upgrading the kernel version to 5.15.0-124-generic on a Ubuntu 22.04 server.
The kernel versions available for installation at the time of referencing the guide may vary, so thoroughly test other versions before installation.
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Access the server you want to apply the kernel update to remotely.
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Check the kernel version of the server.
root@ubuntu2204:~# uname -r 5.15.0-94-generic -
Check the repository information connected to the server.
root@ubuntu2204:~# grep ^deb /etc/apt/sources.list deb http://repo.ncloud.com/ubuntu jammy main restricted deb http://repo.ncloud.com/ubuntu jammy-updates main restricted deb http://repo.ncloud.com/ubuntu jammy universe deb http://repo.ncloud.com/ubuntu jammy-updates universe deb http://repo.ncloud.com/ubuntu jammy multiverse deb http://repo.ncloud.com/ubuntu jammy-updates multiverse deb http://repo.ncloud.com/ubuntu jammy-backports main restricted universe multiverse deb http://repo.ncloud.com/ubuntu jammy-security main restricted deb http://repo.ncloud.com/ubuntu jammy-security universe deb http://repo.ncloud.com/ubuntu jammy-security multiverse -
Check the kernel version provided by the repository.
root@ubuntu2204:~# rm -rf /var/cache/apt/archives/* root@ubuntu2204:~# rm -rf /var/lib/apt/lists/* root@ubuntu2204:~# apt clean root@ubuntu2204:~# apt update Hit:1 http://repo.ncloud.com/ubuntu jammy InRelease Get:2 http://repo.ncloud.com/ubuntu jammy-updates InRelease [128 kB] Get:3 http://repo.ncloud.com/ubuntu jammy-backports InRelease [127 kB] Get:4 http://repo.ncloud.com/ubuntu jammy-security InRelease [129 kB] ... Omitted ... Fetched 11.1 MB in 2s (5,400 kB/s) Reading package lists... Done root@ubuntu2204:~# apt policy linux-image-5.15.0-124-generic linux-image-5.15.0-124-generic: Installed: (none) Candidate: 5.15.0-124.134 Version table: 5.15.0-124.134 500 500 http://repo.ncloud.com/ubuntu jammy-updates/main amd64 Packages 500 http://repo.ncloud.com/ubuntu jammy-security/main amd64 Packages -
Install the viewed version of the kernel.
Carefully review the list of packages being newly installed, updated, or removed. If everything is in order, enterYto complete the installation.root@ubuntu2204:~# apt install linux-{image,headers}-5.15.0-124-generic Reading package lists... Done Building dependency tree... Done Reading state information... Done The following packages were automatically installed and are no longer required: eatmydata libeatmydata1 python-babel-localedata python3-babel python3-certifi python3-jinja2 python3-json-pointer python3-jsonpatch python3-jsonschema python3-markupsafe python3-pyrsistent python3-requests python3-tz python3-urllib3 Use 'apt autoremove' to remove them. The following additional packages will be installed: linux-headers-5.15.0-124 linux-modules-5.15.0-124-generic Suggested packages: fdutils linux-doc | linux-source-5.15.0 linux-tools linux-modules-extra-5.15.0-124-generic The following NEW packages will be installed: linux-headers-5.15.0-124 linux-headers-5.15.0-124-generic linux-image-5.15.0-124-generic linux-modules-5.15.0-124-generic 0 upgraded, 4 newly installed, 0 to remove and 176 not upgraded. Need to get 49.4 MB of archives. After this operation, 231 MB of additional disk space will be used. Do you want to continue? [Y/n] Y ... Omitted ... Found linux image: /boot/vmlinuz-5.15.0-124-generic Found initrd image: /boot/initrd.img-5.15.0-124-generic Found linux image: /boot/vmlinuz-5.15.0-94-generic Found initrd image: /boot/initrd.img-5.15.0-94-generic Found linux image: /boot/vmlinuz-5.15.0-92-generic Found initrd image: /boot/initrd.img-5.15.0-92-generic Warning: os-prober will not be executed to detect other bootable partitions. Systems on them will not be added to the GRUB boot configuration. Check GRUB_DISABLE_OS_PROBER documentation entry. done Scanning processes... Scanning linux images... No services need to be restarted. No containers need to be restarted. No user sessions are running outdated binaries. No VM guests are running outdated hypervisor (qemu) binaries on this host. -
After the installation is complete, check all bootable kernel versions.
root@ubuntu2204:~# dpkg -l | grep linux-image | grep ii ii linux-image-5.15.0-124-generic 5.15.0-124.134 amd64 Signed kernel image generic ii linux-image-5.15.0-92-generic 5.15.0-92.102 amd64 Signed kernel image generic ii linux-image-5.15.0-94-generic 5.15.0-94.104 amd64 Signed kernel image generic -
Configure it so that the most recent kernel version can be selected as the default when booting.
root@ubuntu2204:~# sed -i 's/GRUB_DEFAULT=.*/GRUB_DEFAULT=saved/g' /etc/default/grub root@ubuntu2204:~# grep "GRUB_DEFAULT" /etc/default/grub GRUB_DEFAULT=saved root@ubuntu2204:~# grub-set-default "Advanced options for Ubuntu>Ubuntu, with Linux 5.15.0-124-generic" root@ubuntu2204:~# grub-editenv list saved_entry=Advanced options for Ubuntu>Ubuntu, with Linux 5.15.0-124-generic root@ubuntu2204:~# update-grub Sourcing file `/etc/default/grub' Sourcing file `/etc/default/grub.d/init-select.cfg' Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.15.0-124-generic Found initrd image: /boot/initrd.img-5.15.0-124-generic Found linux image: /boot/vmlinuz-5.15.0-94-generic Found initrd image: /boot/initrd.img-5.15.0-94-generic Found linux image: /boot/vmlinuz-5.15.0-92-generic Found initrd image: /boot/initrd.img-5.15.0-92-generic Warning: os-prober will not be executed to detect other bootable partitions. Systems on them will not be added to the GRUB boot configuration. Check GRUB_DISABLE_OS_PROBER documentation entry. done -
Reboot the server to activate the latest kernel version.
root@ubuntu2204:~# sync;rebootNoteIf the server reboot fails, it means the kernel update was not successfully applied. In this case, see Restore kernel update to revert to the previous kernel version.
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Log in to the server again and check if the new kernel is activated.
root@ubuntu2204:~# uname -r 5.15.0-124-genericNoteTo check if the updated kernel is properly applied, see Checking kernel updates to check the kernel installation status.
Check kernel update
To check if the kernel update was successfully applied, follow these steps:
- Access the server remotely.
- Check if the kernel package is installed.
root@ubuntu2204:~# dpkg -l | grep linux-image-5.15.0-124-generic ii linux-image-5.15.0-124-generic 5.15.0-124.134 amd64 Signed kernel image generic - Check if the initramfs file and vmlinuz file are created in the /boot directory.
root@ubuntu2204:~# ls -l /boot/initrd.img-5.15.0-124-generic -rw-r--r-- 1 root root 46553441 Oct 23 14:48 /boot/initrd.img-5.15.0-124-generic root@ubuntu2204:~# ls -l /boot/vmlinuz-5.15.0-124-generic -rw------- 1 root root 11700328 Sep 28 03:47 /boot/vmlinuz-5.15.0-124-generic - Check if the latest kernel settings are registered in the grub.cfg file.
root@ubuntu2204:~# awk -F"--class" '/menuentry/ && /with Linux/ {print $1}' /boot/grub/grub.cfg | awk '{print i++ " : " $5,$6,$7,$8}' | sed -e "s/'/ /g" 0 : 5.15.0-124-generic 1 : 5.15.0-124-generic (recovery mode) 2 : 5.15.0-94-generic 3 : 5.15.0-94-generic (recovery mode) 4 : 5.15.0-92-generic 5 : 5.15.0-92-generic (recovery mode)
Restore kernel update
If the server fails to restart properly after a kernel update, you must revert to the previous kernel before the update. You can revert it to one of the many installed kernel versions, and this guide describes how to revert the kernel to the version immediately before the update.
To resolve server restart issues, you can attempt server recovery by entering single mode. For more information on how to run reboot in Single Mode, see Server recovery guide.
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In the VPC environment of the NAVER Cloud Platform console, navigate to
> Services > Compute > Server. -
Click the Server menu.
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Select the server to recover from the server image list, and then click the [Server connection console] button.
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Select the previous version as the booting kernel from the grub booting page and reboot.
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Ubuntu 22.04 grub boot page
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After booting is complete, check the kernel version of the server.
root@ubuntu2204:~# uname -r 5.15.0-94-generic -
Check the kernel version that is currently active.
root@ubuntu2204:~# awk -F"--class" '/menuentry/ && /with Linux/ {print $1}' /boot/grub/grub.cfg | awk '{print i++ " : " $5,$6,$7,$8}' | sed -e "s/'/ /g" 0 : 5.15.0-124-generic 1 : 5.15.0-124-generic (recovery mode) 2 : 5.15.0-94-generic 3 : 5.15.0-94-generic (recovery mode) 4 : 5.15.0-92-generic 5 : 5.15.0-92-generic (recovery mode) -
Reset the default kernel version to the previous kernel version when booting.
root@ubuntu2204:~# sed -i 's/GRUB_DEFAULT=.*/GRUB_DEFAULT=saved/g' /etc/default/grub root@ubuntu2204:~# grep "GRUB_DEFAULT" /etc/default/grub GRUB_DEFAULT=saved root@ubuntu2204:~# grub-set-default "Advanced options for Ubuntu>Ubuntu, with Linux 5.15.0-94-generic" root@ubuntu2204:~# grub-editenv list saved_entry=Advanced options for Ubuntu>Ubuntu, with Linux 5.15.0-94-generic root@ubuntu2204:~# update-grub Sourcing file `/etc/default/grub' Sourcing file `/etc/default/grub.d/init-select.cfg' Generating grub configuration file ... Found linux image: /boot/vmlinuz-5.15.0-124-generic Found initrd image: /boot/initrd.img-5.15.0-124-generic Found linux image: /boot/vmlinuz-5.15.0-94-generic Found initrd image: /boot/initrd.img-5.15.0-94-generic Found linux image: /boot/vmlinuz-5.15.0-92-generic Found initrd image: /boot/initrd.img-5.15.0-92-generic Warning: os-prober will not be executed to detect other bootable partitions. Systems on them will not be added to the GRUB boot configuration. Check GRUB_DISABLE_OS_PROBER documentation entry. done -
(Optional) Reboot the server to check whether the server boots up normally with the updated kernel version.
root@ubuntu2204:~# sync;reboot -
(Optional) Log back into the server to check the booting status and the kernel version.
root@ubuntu2204:~# uname -r 5.15.0-94-generic