Skip to main content

First 3 Days with bootc

I decided to spend some time playing with bootc. Mostly I'm inspired by the following articles: 


Day 1

To install bootc in a VM I need an image. bootc-image-builder requires root and I don't want to run this on the host. So I chose CoreOS as the inital system and installed it to QEMU.

I thought it is a great idea to share a folder from host to guest as podman container storage. However, it was not as smooth as I had expected:

  • virtiofsd on Debian is too old, so I set up NFS.
  • rootless podman doesn't work well with NFS.
  • rootfull podman complains upstream fs of overlayfs missing features, the performance was terrible.
I gave up. I guess I'll just use the CoreOS disk, whose size is 10G, not enough.


Day 2

I didn't find a way of resizing a qcow2 image online. On the other hand I figured maybe I don't need build a disk image after all. CoreOS is already based on ostree, maybe I can use `bootc switch`. This is essentially the same approach as in the first blog post.

`bootc switch` just works, it can reboot, but I cannot login (ssh or local). Fortunately (and quite nicely), I can rollback ostree even without logging in, because I can do that with grub.

I suspect it is because some files are overriding the files in the image.


Day 3

I learned that QEMU has builtin samba support, which is much easier to use than NFS.

Eventually I found that it was SELinux that has been messing up. With `restorecon -R` I could login from QEMU terminal, but not ssh. After logging in, `bootc status` threw an error about /boot, so I guess I needed `bootc install` afte rall.

So I just went back to the original solution, just resize the CoreOS image and build bootc image inside CoreOS. It worked this time.

Now I need to complete the loop, the new bootc OS should build itself and automatically update itself. And a few more things to fix:

- /etc/fstab does not work if modified when building the container, I need to create systemd mount files for mounts

- /etc/hostname does not work if modified when building the container, I need to set it after each boot

- Unlike `bootc install`, `bootc-image-builder` does not provide flags to override the bootc repository, so I need to set it after boot

- Transient etc sounds like a good idea, but I'll need to manually configure /boot. I'd like to enable it when the official doc explains more details.


Conclusion:

bootc works and its quite fun. But unfortunately I didn't find a way of actually using it in production yet:

  • I could put it into a VM, but sharing files between host and VM is not pretty at the moment (on Debian stable)
  • I don't trust it as my main server yet, and I don't have other machine to which I can install bootc bare-metal.

I think later I'll spend more time trying to tinker with it.

Labels:

Comments

Post a Comment

Popular posts from this blog

Determine Perspective Lines With Off-page Vanishing Point

In perspective drawing, a vanishing point represents a group of parallel lines, in other words, a direction. For any point on the paper, if we want a line towards the same direction (in the 3d space), we simply draw a line through it and the vanishing point. But sometimes the vanishing point is too far away, such that it is outside the paper/canvas. In this example, we have a point P and two perspective lines L1 and L2. The vanishing point VP is naturally the intersection of L1 and L2. The task is to draw a line through P and VP, without having VP on the paper. I am aware of a few traditional solutions: 1. Use extra pieces of paper such that we can extend L1 and L2 until we see VP. 2. Draw everything in a smaller scale, such that we can see both P and VP on the paper. Draw the line and scale everything back. 3. Draw a perspective grid using the Brewer Method. #1 and #2 might be quite practical. #3 may not guarantee a solution, unless we can measure distances/p...
3 comments
Read More »

Hardware Password Manager

[Updates 2025-01-20] The original blog post assumes that all passwords are stored in one password manager, and the password manager either unlocks everything or nothing (e.g. Keepass). After discussing with friends, I realized that if I use something like pass , and I use a hardware GPG token, I can actually store and sync all encrypted passwords to all devices, because I will only decrypt the passwords on demand, and the computer will not see the GPG private key. The compromise is that the computer will see the list of all password entries (e.g. accounts), as well as a few other issues . I've been using Keepass for many years. I don't use online password services because I cannot fully trust them. Besides, I may not always have Internet connection, which is why I also don't use a self-hosted service. Everything has been working fine, until I turn my paranoid knob to the max. Here's the thought experiment . The Imaginary Scenario Let's say I have 100 PCs for differe...
Post a Comment
Read More »

ESP32S3: Flash Encryption and Secure Boot

Flash encryption and secure boot are useful security features for ESP32S3 chip. While not perfect, they definitely make it harder to extract the secrets in the chip. However, it is tricky to enable both features at the same time. The topic is actually discussed in the official documentation: ESP32S3 Security Features Security Features Enablement Workflows Especially, the second one mentioned it is recommended to enable flash encryption before secure boot. But I still find the documentation confusing. In the end I was able to successfully enable both, here's my findings. My Understanding After my adventure, here's what I think could have worked. WARNING, this is untested. Follow  Security Features Enablement Workflows : Burn all the keys, as long as their purpose eFuses and read/write protections Burn other security eFuses, but DO NOT burn ENABLE_SECURITY_DOWNLOAD in the middle, which is mentined at the end of the instruction for both flash encryption and secure boot. Burn...
Post a Comment
Read More »