bootable flash for centos 7

General support questions
Whoever
Posts: 1357
Joined: 2013/09/06 03:12:10

Re: bootable flash for centos 7

Post by Whoever » 2021/04/06 06:23:29

Akeo wrote:
2021/04/05 19:27:08

Obviously, this means that this will create problems with ISO mode, which is not a big deal, as we just can do what with the couple other distros that have chosen to go down that road and force DD mode always. But I sure wouldn't mind if CentOS maintainers would look around at what other distro maintainers have chosen to do, and possibly try to understand why, "surprisingly", the most popular distros are still not jumping onto the "DD only" bandwagon (which, again, has to do with trying to provide the users with choice and ultimately improving their experience).
I think that you misunderstand what CentOS is, and hence, where to direct your ire.

If there is a problem with the CentOS 8 installation, the CentOS team doesn't have control over that: Red Hat does.

In the example you gave, it's not clear that there was any real issue with the DD approach. Just perhaps a misunderstanding. One of the people giving advice seems to have some gaps in their knowledge (specifically, what LVM does), so it's not clear that the advice took the person asking the original questions down the correct path.

Akeo
Posts: 10
Joined: 2021/04/05 15:55:46

Re: bootable flash for centos 7

Post by Akeo » 2021/04/06 11:26:02

"it's not clear that there was any real issue with the DD approach. Just perhaps a misunderstanding."

How I wish people in this forum applied the same leniency to the ISO/File copy approach used by Rufus, instead of being insta-loaded to blaming it for anything and everything that goes wrong, even when it has nothing to with it.

And that's the root of my problem here. If there is a problem with a DD created media, people will spend time analysing why there might be an issue and try to understand what caused it, instead of defaulting to blaming the manner in which the media has been created or spewing complete bullshit about how Rufus is "silently corrupting" the media (how convenient for an adjective, because then you don't have to explicitly point the finger at what exactly it is doing to corrupt the media, and where exactly that happens).

Up to CentOS 8.2, the file copy/ISO copy method employed by Rufus was a perfectly valid method of installing CentOS, that was supported by the installer. People appeared to use that just fine, and, despite what many here are hell bent on arguing, from the lack of echoes I received on either the issue tracker or through e-mail, I am confident that whatever issue some had with this method during their installation had little to do with the fact that they were using ISO copy (which is something that can be a lot more convenient than DD copy, especially as UEFI boot makes that quite attractive). And yet, instead of promoting a nuanced "it's not clear that there was any real issue with the ISO approach. Just perhaps a misunderstanding.", as people are doing when the situation is reversed, boy are suddenly things different, and is the blame shifted entirely to the manner in which the media was created if it turns out that the user did not use DD, even as, up until 8.3, the installation process was, again, fine with supporting a non DD created media.

And, for the record, my current understanding is that the reason why ISO copy/File copy started to fail in CentOS 8.3, has something to do with this commit, that introduced a regression with regards to defaulting to using the autodetected media when it is provided, which is what ISO mode does.

Sadly however, because the default stance I am seeing from these forums is to just bash the file copy method to a FAT32 drive (which, by the way, does not require using a utility like Rufus if your target is a UEFI system, and can accomplished just as easily entirely manually), instead of trying to properly analyse what might have happened with media detection between 8.2 and 8.3 in order to help CentOS users who may want to have a greater choice than just "one method (DD) to rule them all", because it has not yet been reported to Red Hat that they have actually introduced a regression in their installer, you end up with the usual self serving circle of "The defaults of Rufus are bad, don't use that ever", even if, if you are as nuanced in your approach as not wanting to defaulting to pinning the blame on DD when you see a DD issue, you should agree that the actual situation with regards to ISO mode situation is a lot less clear cut than "Rufus is simply doing bad job".

In short, I'd appreciate if folks here realized that defaulting to pointing the finger to one utility, when that utility has actually helped people creating CentOS bootable media without much trouble for years (there was one small issue when CentOS 7 was introduced, that had to do with space conversion in labels, but which was relatively quickly fixed, and until 8.3, I have not been made aware of any specific issue that led to problems with CentOS installation), would instead spend some of that energy doing what I just did (and what I will argue the previous poster also appears to advocate), which is trying to analyse what exactly might be creating the issue, and, possibly report it to the appropriate place (which may actually be with the OS maintainers), if turns out to be a regression.

Who knows, you might actually end up helping CentOS users, by providing them with a greater choice with regards to the methods they can use to create installation media, regardless of whether the one they end up using might be the one you would prefer them to use...

User avatar
TrevorH
Site Admin
Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: bootable flash for centos 7

Post by TrevorH » 2021/04/06 13:13:43

All CentOS isos are isohybrid so that they dual boot on either sort of hardware.

We have had numerous reports of Rufus in its default configuration, breaking the isos as they are copied to the USB stick. Since I don't have a Windows machine on which to test that scenario, I politely tell people that Rufus has been known to do this and since I have no knowledge of the product, I tell people to use something else.

The consequence of booting the resulting image on a machine in UEFI mode is that it boots in legacy BIOS mode and proceeds to install in legacy BIOS mode. That then mucks up all previously installed operating systems that were installed in UEFI mode and needs special action to sort out. So rather than do this to users, we recommend other tools.

If you'd care to amend Rufus so that it auto-detects isohybrid images and does the right thing out of the box then I'll tell people that they can use it.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

Akeo
Posts: 10
Joined: 2021/04/05 15:55:46

Re: bootable flash for centos 7

Post by Akeo » 2021/04/18 23:51:22

If you'd care to amend Rufus so that it auto-detects isohybrid images and does the right thing out of the box then I'll tell people that they can use it.
This is a two way street. If you'd care to look into the actual issue, understand that DD mode is not a panacea, and make sure that you liaise with Red Hat so that they fix regressions that made the newer Red Hat and CentOS cease to work with ISO mode, whereas previous versions were supporting it just fine before, maybe we could get somewhere.

But of course, it appears a lot easier to point the finger at the utility, and completely ignore the fact that said utility was working just fine, in ISO mode, with CentOS 8.2...

At this stage, given the stubbornness of some of the people from this forum into not even wanting to consider that, maybe, it's not all black and white, I have no choice but to continue to advocate that the actual right thing to do would be to fix the obvious Red Hat regression. But of course, even as it should be considered as a fair assessment that, maybe there is something that Red Hat/CentOS needs to fix, this stance is likely to be dismissed as a "Rufus developer is just unhappy that his utility doesn't work in ISO mode".

So please feel free to continue to take the easy way out with users that report a regression that should warrant at least a little bit of analysis, and dismiss those as a pure image creation utility issue. Meanwhile, I will certainly be more than happy to recommend users who are interested in Linux to turn to the many distributions that understand that making an ISOHybrid compatible with DD mode only is not that great an idea, as it ultimately ends up restricting what a user can do (for instance, ISO mode support can be critical to installing a distro on a Raspberry Pi, in full UEFI mode)...

User avatar
TrevorH
Site Admin
Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: bootable flash for centos 7

Post by TrevorH » 2021/04/18 23:56:06

We've been fielding reports of broken isos from using Rufus for years, it's not something that only just broke.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

Akeo
Posts: 10
Joined: 2021/04/05 15:55:46

Re: bootable flash for centos 7

Post by Akeo » 2021/04/19 00:02:51

I tested CentOS 8.2 in ISO mode, and it worked fine in ISO mode. Same test with 8.3, and it was broken.

You can actually test this. And you got explicit reports of the 8.3 vs 8.2 regression (which, as usual, you dismissed as "Don't use Rufus").

Sorry, but your assertion does not stand the test of scrutiny when I am not the only person reporting that ISO mode was working fine for CentOS 8.2 and got broken in 8.3. And again, you are completely ignoring everything that points to maybe wanting to have both DD and ISO mode working for CentOS/Red Hat (since it can help with UEFI installs, independently of Rufus), rather than limiting users to only DD.

User avatar
TrevorH
Site Admin
Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: bootable flash for centos 7

Post by TrevorH » 2021/04/19 00:11:17

I checked our wiki page and I added the warning about using rufus with the wrong options back in 2019-07 and I would only have done that after receiving sufficient reports of it breaking things to verify that it was true.

I don't run Windows so I've never even downloaded rufus. Do not blame me for not personally verifying that your code is broken as it's not something I can do. I collated a number of reports of it breaking and only when I was sure that it was indeed the case did I add the warning to that page. If you don't want to believe that your program breaks our isos then don't. We'll just leave the wiki page not there recommending against its use.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

Akeo
Posts: 10
Joined: 2021/04/05 15:55:46

Re: bootable flash for centos 7

Post by Akeo » 2021/04/19 00:16:25

Awesome. If you don't want to believe that Red Hat introduced a regression, then don't.

What a nice day for putting one's fingers in their ears...

User avatar
TrevorH
Site Admin
Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: bootable flash for centos 7

Post by TrevorH » 2021/04/19 00:26:43

The way it works is we put out iso images which are correct.
Your program writes those to media and corrupts them.

Under what circumstances are we going to recommend that people use a program that corrupts the data that they're about to use to install with?

They are iso images, why are you ever trying to modify them? They are already how they should be and changing them breaks them. So why do it? You're not the one that ends up fielding complaints about how we've rendered someone's system unable to boot Windows. Given the severity of the results of the problem, there is zero chance that we'll tell people to use Rufus until it's fixed.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

Akeo
Posts: 10
Joined: 2021/04/05 15:55:46

Re: bootable flash for centos 7

Post by Akeo » 2021/04/19 00:53:50

The thing that you don't seem to grasp is that, ISO mode is really "extract the ISO content to a FAT partition as is, and boot that".

The only file we may possibly alter is grub.cfg to update the search label, since Red Hat and derivatives have failed to take a look at what other distros do to ensure that extracted ISO content boots in this fashion (for instance, Debian look for an installation marker/file on the media, and Arch at least make sure that the ISO labels they use are compatible with FAT labels). And we may add some BIOS bootloaders that did not exist (GRUB, Syslinux) in MBR/VBR if needed, but that's about it.

This is yet something else you can test if you want, by comparing the md5 of the files Rufus extracts with the ones from the original ISO (which, by the way, is something that Ubuntu does as part as their boot process, and which confirms that, no, Rufus does not "corrupt" the data).

Oh, and the thing I've been trying to point out over and over again is that ISO mode is really something that people should be able to use to create media to boot on UEFI platforms, without using Rufus.

If you don't have access to Windows, you can replicate exactly what Rufus does by creating a FAT partition, extracting the whole ISO content there, and editing grub.cfg so that the label matches the FAT label of your partition. Do that with CentOS 8.2, and you'll find that you can install it on a UEFI system (and you did not use Rufus). Do that with 8.3, and it no longer works. Again, you can test this, independently of using Rufus.

I'd advise you to spend some time trying to educate yourself with regards to Rufus allegedly "corrupting" the ISO data, but all the attempts I have made at that so far have been ignored. So, as long as you're going to ignore the fact that "ISO mode" is not actually something special that Rufus does, that the vast majority of distros out there understand that it can be beneficial for users to be able to extract the whole ISO content onto a FAT file system and boot that on UEFI (which is really what ISO mode of Rufus does for UEFI), and that 8.2 and 8.3 behave differently in that respect, most likely due to the Red Hat commit that I have repeatedly pointed to, I'm just going to ignore your false allegations that Rufus is trying to modify images, because it just demonstrates that you haven't really looked at the nature of the problem to instead assume that it could only be some utility, which you know very little about, being the root of all evil.

Post Reply