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An Ubuntu kernel bug causes container crashes

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Re: An Ubuntu kernel bug causes container crashes

#81

Post by gtirloni »

capableweb wrote: post #58
akx wrote: post #25

Earlier quoted context omitted.

> have to follow the procedure for restoring from backup or re-mounting the root volume on an alternate house to revert the kernel version being run. Or add `systemd.mask=docker.service` to your boot parameters to prevent Docker from starting.

Which, if your server is stuck in a infinitive "boot -> docker starting -> container starting -> crashing kernel -> reboot" loop, you won't ever get a chance of actually adding anything to your boot parameters.

Sorry, what? You don't lose complete control of a server because it's rebooting nonstop.

Re: An Ubuntu kernel bug causes container crashes

#82

Post by gtirloni »

sofixa wrote: post #39
markstos wrote: post #3

This was even worse than the headline made it sound. If you had `unattended-upgrades` running and had the "automatic reboot" option enabled, then all your Ubuntu 20.04 servers running Docker would reboot themselves and not come back up. First, the bug was in a security branch. Second, it wasn't just the containers that crashed. If you booted containers on boot via Docker, then the host OS kernel-panicked and crashed…

> If you had `unattended-upgrades` running and had the "automatic reboot" option enabled, then all your Ubuntu 20.04 servers running Docker would reboot themselves and not come back up. Isn't the common wisdom that you should have them enabled, but staggered across hours/days?

Not a huge Debian/Ubuntu user but I think the systemd timer that triggers the unattended updates has a random delay added to it. I don't know of it's hours or just seconds.

Re: An Ubuntu kernel bug causes container crashes

#83

Post by ape4 »

withinboredom wrote: post #42
_y5hn wrote: post #21

Earlier quoted context omitted.

Wouldn't rollback of kernel be a choice in grub menu? It's pretty standard for all distros to have that choice.

That usually requires physical access to the server to select it during boot.

If its in the cloud you'd have a virtual console.

Re: An Ubuntu kernel bug causes container crashes

#84

Post by jve »

atoav wrote: post #16

The cost of complexity showing itself. A sysadmin friend of mine is totally against docker and his reason is that he wants as little complexity as is needed on his systems. Complexity, he says, leads to emergent behavior.

Docker actually helps managing complexity, by putting bits and pieces, scattered on the floor and putting them into a single cardboard box.

- If you throw the box out, you know you did no harm to other boxes.

- If you change your floor, you know you didn't wipe out something useful.

- Aaand you can `git switch` to a well known state

Ofcourse it's not 100% like that, in reality you still have to have some kind of consistency on where you put your docker-compose file, Dockerfiles for all the boxes, where you mount your volumes (in some folder or scattered all over system), maybe dealing with host firewall, dealing with not-commiting secrets into git etc.

But overall, it's very positive - docker-compose is (almost) one-stop file you need to see all your references to volumes, Dockerfile, network configurations, environment files with secrets.

Re: An Ubuntu kernel bug causes container crashes

#85

Post by nyc_pizzadev »

Interesting, around the same time both of my Ubuntu 20 laptops (Dell and Lenovo) started having major problems connecting to my home wifi. It only affects these 2 laptops, all my other devices have no problems. Before reading this I did think this was a result of a bad Ubuntu update. Given they switched kernel versions, my guess is that this is infact the culprit. Very annoying, it takes me anywhere from 5 to 45 minutes to establish a wifi session now.

Re: An Ubuntu kernel bug causes container crashes

#86

Post by Gordonjcp »

atoav wrote: post #16

The cost of complexity showing itself. A sysadmin friend of mine is totally against docker and his reason is that he wants as little complexity as is needed on his systems. Complexity, he says, leads to emergent behavior.

Okay, so presumably they either sysadmin one single site, or an entire fleet of individual servers each for one specific task?

Either way, I dont think they understand what Docker is, what it's for, and why it makes things less complicated.

Re: An Ubuntu kernel bug causes container crashes

#87

Post by vbezhenar »

kuschku wrote: post #56
atoav wrote: post #27

Earlier quoted context omitted.

Or it could not be triggered if you don't use containers.

It could also be triggered by application sandboxing solutions that aren't containers.

That's another reason to avoid those appimages and snaps.

Re: An Ubuntu kernel bug causes container crashes

#88

Post by iam-TJ »

mobilio wrote: post #2

This isn't only bug. I've recently migrated to Ubuntu 22.04 and got this: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1971505 https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1970453 on HP ProLiant servers.

I've just added some info to those bugs on a possible upstream stable fix.

Re: An Ubuntu kernel bug causes container crashes

#89

Post by dncornholio »

jve wrote: post #84
atoav wrote: post #16

The cost of complexity showing itself. A sysadmin friend of mine is totally against docker and his reason is that he wants as little complexity as is needed on his systems. Complexity, he says, leads to emergent behavior.

Docker actually helps managing complexity, by putting bits and pieces, scattered on the floor and putting them into a single cardboard box. - If you throw the box out, you know you did no harm to other boxes. - If you change your floor, you know you didn't wipe out something useful. - Aaand you can `git switch` to a well known state Ofcourse it's not 100% like that, in reality you still have to have some kind of cons…

What you are saying is actual complexity. A box can be a machine instead of container and all your points will still stand but with less complexity.

Re: An Ubuntu kernel bug causes container crashes

#90

Post by dncornholio »

atoav wrote: post #16

The cost of complexity showing itself. A sysadmin friend of mine is totally against docker and his reason is that he wants as little complexity as is needed on his systems. Complexity, he says, leads to emergent behavior.

Docker hasn't solved any problem for me, so I don't see any use in using it. Meanwhile I have multiple junior devs asking me docker stuff so they can run stuff localy. When I ask them why even use docker, they always say that some tutorial told them to.

This is when I introduce them to something called VirtualBox and then their eyes go bright with wonder on how simple that works.

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