Introduction
How to Upgrade Linux Kernel in CentOS 7
1. Check the Current Kernel Version
Before you upgrade the Linux kernel, you need to check the current version of the kernel. To do this, open a terminal window and type the following command:
uname -r
This will display the current version of the kernel.
2. Download the Latest Kernel
The next step is to download the latest version of the kernel. You can do this by visiting the official website of the Linux kernel. Once you have downloaded the kernel, extract the files to a directory.
3. Install the Kernel
Once you have downloaded and extracted the kernel files, you need to install them. To do this, open a terminal window and navigate to the directory where you extracted the files. Then, type the following command:
sudo make install
This will install the kernel.
4. Update the Boot Loader
Once the kernel is installed, you need to update the boot loader. To do this, type the following command:
sudo grub2-mkconfig -o /boot/grub2/grub.cfg
This will update the boot loader with the new kernel.
5. Reboot the System
Finally, you need to reboot the system for the changes to take effect. To do this, type the following command:
sudo reboot
This will reboot the system and the new kernel will be loaded.
Introduction
The Linux kernel is the foundation on which all Linux distributions operate. It is open-source software – anyone can decompile, examine, and modify the code.
Updated versions of the kernel can improve security, add functionality, and improve the speed at which the operating system functions.
This guide will instruct you on how to upgrade the Linux kernel on CentOS 7.
Prerequisites
- A CentOS server
- Access to the command-line / terminal access
- Sudo privileges
- A recent backup of your system
Steps to Update CentOS Kernel Version
The yum package manager allows kernel updates. However, CentOS does not offer the latest kernel version in the official repository.
To update the kernel on CentOS, you’ll need to install a third-party repository called ElRepo. ElRepo offers the latest kernel version available from kernel.org.
The official releases are tested to ensure they work properly and do not destabilize applications and OS functions. There are two types of Linux kernel versions:
- Stable long-term supported kernel release – updated less frequently, but supported longer.
- Mainline kernel release – a shorter support term but more frequent updates.
Step 1: Check Your Current Kernel Version
To check current kernel version on CentOS, open a command-line interface and enter following command:
uname -msrThe system should return with an entry that appears like this:
Output
Linux 3.10.0-862.el7.x86-64 x86-64The output indicates which version of the kernel you are currently running, and on which architecture it’s based on.
For additional information, refer to our detailed guide on how to check Linux kernel version.
Step 2: Update CentOS Repositories
Prior to upgrading the kernel, all packages must be updated to the latest version.
To update CentOS software repositories, use the command:
sudo yum -y updateYour software repository is now updated. This ensures you have access to the latest version of the kernel.
Note: The -y switch tells the system to say “yes” to any prompts that may pop up.
Step 3: Enable the ELRepo Repository
To install the new kernel version, a new repository (ELRepo repository) needs to be enabled.
In a terminal window, type:
sudo rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.orgThe previous command installs the GPG key for the ELRepo repository. This is important – CentOS will not allow the installation of an unsigned software package. The GPG key provides a digital signature to verify that the software is authentic.
Next, install the ELRepo repository by executing the following command:
sudo rpm -Uvh https://www.elrepo.org/elrepo-release-7.0-3.el7.elrepo.noarch.rpmAllow the system to finish performing the operation.
Step 4: List Available Kernels
To list available kernels, enter:
yum list available --disablerepo='*' --enablerepo=elrepo-kernelThe system should return a list of available modules. In the list, note the line that says kernel-lt – signifying a stable long-term support release – or kernel-ml – which indicates a mainline release, with a shorter support term but with more frequent updates.
Next, look at the right-hand column, and notice a series of letters and numbers (which looks something like ‘4.4.113-1.e17.elrepo’). This is the kernel version.
Use these two pieces of information to decide which kernel version you want to install. As you can see, the Linux 5 kernel is the latest mainline release.
Step 5: Install New CentOS Kernel Version
To install the latest mainline kernel:
sudo yum --enablerepo=elrepo-kernel install kernel-ml
To install the latest long-term support kernel:
sudo yum --enablerepo=elrepo-kernel install kernel-lt
The system should download the software, then prompt you to confirm that it’s OK to install – type y and press enter.
Allow the process to complete.
Step 6: Reboot and Select the New Kernel
Reboot your system by running the command:
rebootYou’ll be presented with the GRUB, or boot menu.
Use the arrow keys to select the Linux kernel you have just installed, then press Enter. Your operating system should boot normally.
Step 7: Verify Functionality
Take a moment to check the functionalities of your CentOS system. Does all your software launch correctly and without errors? Do all your network functions work correctly?
Put your new kernel through its paces so all errors are identified and fixed in time. Or, if there aren’t any fixes, you can opt to switch back to the old kernel.
Step 8: Set Default Kernel Version
Once you confirm that the new kernel is compatible and working correctly, you’ll want to edit the GRUB boot utility so that, by default, it loads your new kernel.
Navigate to /etc/default/ and open the grub file with your text editor. Or, type the following in the terminal:
sudo vim /etc/default/grubOnce the file opens, look for the line that says GRUB_DEFAULT=X, and change it to GRUB_DEFAULT=0 (zero). This line will instruct the boot loader to default to the first kernel on the list, which is the latest.
Save the file, and then type the following command in the terminal to recreate the kernel configuration:
sudo grub2-mkconfig -o /boot/grub2/grub.cfgReboot once more:
rebootVerify that the boot loader is set to load the latest kernel by default.
Conclusion
By following this guide, you have updated/upgraded the CentOS Kernel to the latest stable version with ELRepo.
How to Upgrade Linux Kernel in CentOS 7
Upgrading the Linux kernel in CentOS 7 is a relatively straightforward process. The kernel is the core of the operating system and is responsible for managing the system’s resources and providing a platform for applications to run on. Keeping the kernel up to date is important for ensuring the system is secure and stable. This guide will walk you through the steps of upgrading the Linux kernel in CentOS 7.
Prerequisites
- A server running CentOS 7.
- Root access to the server.
Step 1: Check the Current Kernel Version
Before upgrading the kernel, it is important to check the current version. This can be done by running the following command:
uname -rThis will output the current kernel version. Make a note of this for later.
Step 2: Install the Latest Kernel
The next step is to install the latest kernel. This can be done by running the following command:
yum update kernelThis will install the latest version of the kernel. Once the installation is complete, reboot the server to apply the changes.
Step 3: Verify the New Kernel Version
Once the server has been rebooted, it is important to verify that the new kernel version has been installed. This can be done by running the following command:
uname -rThis will output the new kernel version. Compare this to the version you noted earlier to verify that the upgrade was successful.
Conclusion
You have now successfully upgraded the Linux kernel in CentOS 7. Keeping the kernel up to date is important for ensuring the system is secure and stable. If you have any questions or feedback, feel free to leave a comment below.
