Ubuntu Kernel version upgrade procedure.
Hi,
Query 1:
When I installed ubuntu LTS version 18.04.3, I could see kernel version as 4.15.0-144-generic, but as mentioned kernel for 18.04.3 is 5.3.
When I installed ubuntu LTS version 18.04.5, I could see kernel version as 4.15.0-122-generic, but as mentioned in official site Kernel version for 18.04.5 is 5.4.
Question: why Ubuntu 18.04.5 or .3 is coming up with 4.15 version, instead of official kernel?
Query 2:
During HWE kernel release, say for ex 18.04.3 which will have a support for 6months, during that time span if any security fix goes in? the version would be 4.15.0-x+1?
During next HEW release which will change in kernel version 4.15.0-x-y x or y?
Query 3:
Say, I'm in 18.04.3 with kernel version as 4.15.0-144-generic, if I want to upgrade to any other path on the fly. How can we do it? where all those release security/patch kernel version maintained?
Query 4:
Say, I'm in 18.04.3 with kernel version as 4.15.0-144-generic, If I upgrade kernel version(HEW) using apt command line tool (sudo apt-get --install-recommends linux generic hwe-18.04), it is upgrade to latest 5.4.xx.xx. So what is the difference in upgrading kernel or move to 18.04.5 ? Because 18.04.5 has a 5.4 kernel version.
Query 5:
What is the difference between dist-upgrade and apt-get --install-recommends linux generic hwe-18.04?
Re: Ubuntu Kernel version upgrade procedure.
If the system is running OK and all hardware is working then I wouldn't worry about the kernel. Stop chasing version numbers unnecessarily and you'll have less worry.
Re: Ubuntu Kernel version upgrade procedure.
1: Every LTS release of Ubuntu comes with 2 kernel lines: the standard kernel and the HWE kernel. You can switch from one to the other, if you like, and both are supported for the full support period of the release. The standard kernel remains at the same version throughout its life. For 18.04, that's 4.15.0, for 20.04 it's 5.4.0. The HWE kernel is upgraded 4 times in 6 month intervals, to the kernels used by the following Ubuntu releases. The HWE kernel for Ubuntu 18.04 is now 5.4, which is also the standard kernel for 20.04, and the HWE kernel for 20.04 is now 5.11, which is also the kernel for 21.04. Whether you get the standard or HWE kernel by default, depends on the live disk you used for installation. When you install regular upgrades, the version number of your Ubuntu system may increase from 18.04.2 to 18.04.3 etc., but that does not mean you switch from the standard kernel to the HWE kernel or back. Both kernels are official.
2: When you get a security fix to kernel 4.15.0-155, you'll get kernel 4.15.0-156. Or -157 or -158, as sometimes some numbers get skipped.
3: To switch between the standard kernel and the HWE kernel, you can install the appropriate metapackage. For 18.04, that's linux-generic for the standard kernel or linux-generic-hwe-18.04 for the HWE kernel. Unless you don't want the generic kernel. Ubuntu Studio uses the lowlatency kernel. Reboot into the kernel you want, then you can remove the other.
4: As explained above, 18.04.5 doesn't have one specific kernel; it has two.
5: The apt-get dist-upgrade will install patches for the currently installed kernel line (and for all other packages), the other command is to switch from the 4.15 to the 5.4 kernel line. Note that some dashes from your command are missing.
Re: Ubuntu Kernel version upgrade procedure.
Thanks for replying.
Query:1
what is the difference between standard kernel and HWE kernel?
Query:2
If I'm in 18.04.3 right now, and have some security vulnerabilities with the existing kernel(4.15.0-122-generic). what should we upgrade to 18.04.4/5 or should we just upgrade HWE kernel(5.4.0-133-generic or say that security issue may fixed in 4.15.0-133-genric?
what should be difference, as ubuntu 18.04.4 may have all those issue already fixed?
Re: Ubuntu Kernel version upgrade procedure.
1: The standard kernel on Ubuntu 18.04 is 4.15, the HWE kernel is 5.4. The difference is that 5.4 is newer. It has better support for more recent hardware, but also has more bugs. Your choice. Both kernels get regular bugfixes, in particular security fixes, but no support for new hardware. And if you've got recent hardware, don't run 18.04. Use 20.04 instead.
2: If you're affected by a bug in 4.15.0-122, just install the regular upgrades waiting for you. That will install kernel 4.15.0-156. Actually, install that upgrade anyway, along with all other available upgrades, even if you're not aware of any problems that could be solved by this. The idea behind (semi-)automatic upgrades is that you don't have to worry about them. It works very well, 99.99% of the time.
Actually, if your system tells you you're at 18.04.3, there must be upgrades waiting or something is really wrong. The version number should have incremented to 18.04.4 in January 2020 and to 18.04.5 in July 2020. This version number doesn't mean a lot, but it does tell that the package containing the version number is at the stage it had somewhere between July 2019 and January 2020.
There's no such thing as upgrading to 18.04.4. 18.04.3 is 18.04 with all upgrades released until July 2019, 18.04.4 is 18.04 with all upgrades released until January 2020 and 18.04.5 is 18.04 with all upgrades released until July 2020.
Re: Ubuntu Kernel version upgrade procedure.
Quote:
What is the difference between dist-upgrade and apt-get --install-recommends linux generic hwe-18.04?
I quote what the man (manual) page for apt-get says about "dist-upgrade:"
Quote:
dist-upgrade
dist-upgrade in addition to performing the function of upgrade, also intelligently handles changing dependencies with new versions of packages; apt-get has a "smart" conflict resolution system, and it will attempt to upgrade the most important packages at the expense of less important ones if necessary. The dist-upgrade command may therefore remove some packages. The /etc/apt/sources.list file contains a list of locations from which to retrieve desired package files. See also apt_preferences(5) for a mechanism for overriding the general settings for individual packages.
Regards
Re: Ubuntu Kernel version upgrade procedure.
Well... LOL.
I quite and easy thing for you do do would to verify if you are actually HWE or not for your release version...
Code:
uname -r
apt-cache show linux-generic-hwe-$(lsb_release -sr) | awk '/Depends:/ {print $2 ", Kernel Version = " $4}' | sed 's/..$//'
sudo apt list | grep linux-generic-hwe-$(lsb_release -sr)
- The first will show which kernel you are running on currently.
- The second will show you which kernel you should be running on if your were in an HWE series for your release.
- The third will show output if you have HWE installed for your release, or be blank if not installed.
Re: Ubuntu Kernel version upgrade procedure.
thank you all.
It pretty much answer all my doubts, just one more small query.
1) when we ran apt-get dist-upgrade, we could see point release 18.04.3 upgrade to 18.04.4/5 but kernel (uname -r) was same only. why it is so? kernel should also update right?
2) From 18.04.3, we do just apt-get upgrade we would get all latest package and bug fixes? or we need to go to 18.04.4/5 to have latest bug fixes after jan 2020?
Re: Ubuntu Kernel version upgrade procedure.
query 1: HWE kernel I know how to upgrade, but how to upgrade Standard release kernel(4.15)?
query 2: IF I'm in 18.04.3, and I want all latest security fixes and bug fixes, Should I move to latest point release or can get all bug fix on current release by upgrading Kernel.?
Re: Ubuntu Kernel version upgrade procedure.
Have you rebooted yet?
Kernel updates require a reboot in order to load the new kernel.
Quote:
we do just apt-get upgrade we would get all latest package and bug fixes?
No.
apt-get upgrade is the weakest (or some say safest) apt-get command as it only updates packages already installed,
but some updates will require installing new packages.
Chances are at some point when running apt-get upgrade it'll state that some packages will have be to be held back.
For full updates run the dist-upgrade command, or run apt commands such as
Code:
sudo apt full-upgrade
Those commands will install new packages when the update requires it.