add boot tiny linux

Author: blueskyson

_posts/2025/2025-06-01-ubuntu-24-k8s-cluster.md

@@ -2,7 +2,7 @@
 title: Build a Kubernetes Cluster on Ubuntu 24
 image: /assets/img/default-banner.jpg
 author: jack
-date: 2025-05-27 20:55:00 +0800
+date: 2025-06-01 20:55:00 +0800
 categories: [blog, linux]
 tags: [linux]
 math: false

_posts/2025/2025-07-09-boot-tiny-linux.md

@@ -0,0 +1,165 @@
+---
+title: Build a Kubernetes Cluster on Ubuntu 24
+image: /assets/img/default-banner.jpg
+author: jack
+date: 2025-07-09 20:55:00 +0800
+categories: [blog, linux]
+tags: [linux]
+math: false
+pin: false
+---
+
+This post documents my process of manually downloading, configuring, and compiling Linux kernel (v6.12) on an Ubuntu 24.04 machine.
+
+## Installing Required Tools
+
+To compile the Linux kernel, several development tools and libraries are needed. You can install them with the apt package manager:
+
+```bash
+sudo apt update
+sudo apt install -y git build-essential flex bison bc libncurses-dev libssl-dev libelf-dev
+````
+
+Brief explanation of each package:
+
+* `build-essential`: Includes `gcc`, `make`, and other essential build tools
+* `flex`, `bison`: Needed for building the configuration menu
+* `bc`: A math utility used in kernel Makefiles
+* `libncurses-dev`: Provides TUI interface for `make menuconfig`
+* `libssl-dev`, `libelf-dev`: Required by some optional modules
+
+## Downloading the Linux Kernel Source Code
+
+I chose the latest mainline version, v6.12. Use the following command to clone it:
+
+```bash
+git clone --depth=1 --branch=v6.12 git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
+cd linux
+```
+
+The `--depth=1` option fetches only the latest commit, which makes the download faster.
+
+## Generating a Minimal Configuration with tinyconfig
+
+To quickly produce a minimal working kernel, I used `tinyconfig`:
+
+```bash
+make tinyconfig
+```
+
+This generates a `.config` file that enables only the most essential kernel features.
+
+## Compiling the Linux Kernel
+
+Now compile the kernel:
+
+```bash
+make -j$(nproc)
+```
+
+`$(nproc)` uses all available CPU cores for faster build.
+
+After compilation, the output image will be located at:
+
+```none
+./arch/x86/boot/bzImage
+```
+
+`bzImage` is a bootable Linux kernel image, short for "big zImage". It is a self-extracting compressed format mainly used for x86/x86\_64 architectures.
+
+You can check its file type with:
+
+```bash
+file arch/x86/boot/bzImage
+```
+
+## Booting the Kernel with QEMU
+
+First, install QEMU:
+
+```bash
+sudo apt install qemu-system-x86
+```
+
+Then boot the kernel:
+
+```bash
+qemu-system-x86_64 -kernel arch/x86/boot/bzImage
+```
+
+Unfortunately, the screen only showed:
+
+```
+Booting from ROM...
+```
+
+And nothing else followed—no kernel messages appeared. This usually means the kernel lacks the drivers necessary to output to the display.
+
+> Tip: After clicking into the QEMU window, your mouse will be captured. Press `Ctrl + Alt + G` to release it.
+
+![](https://raw.githubusercontent.com/blueskyson/image-host/master/2025/boot-tiny-linux-1.png)
+
+## Configuring menuconfig
+
+After closing the QEMU window, run `menuconfig` to modify kernel settings (make sure `libncurses-dev` is installed):
+
+```bash
+make menuconfig
+```
+
+**Enable TTY Support**
+
+Navigate to:
+
+```none
+Device Drivers  --->
+  Character devices  --->
+    <*> Enable TTY
+```
+
+![](https://raw.githubusercontent.com/blueskyson/image-host/master/2025/boot-tiny-linux-2.png)
+
+> Use arrow keys to navigate and press `Y` or the spacebar to enable the option.
+
+This setting enables support for TTY devices (i.e., text console and serial output).
+
+**Enable printk Support**
+
+Also enable the kernel logging mechanism:
+
+```none
+General setup  --->
+  Configure standard kernel features (expert users)  --->
+    [*] Enable support for printk
+```
+
+![](https://raw.githubusercontent.com/blueskyson/image-host/master/2025/boot-tiny-linux-3.png)
+
+Save your configuration and recompile:
+
+```bash
+make -j$(nproc)
+qemu-system-x86_64 -kernel arch/x86/boot/bzImage
+```
+
+![](https://raw.githubusercontent.com/blueskyson/image-host/master/2025/boot-tiny-linux-4.png)
+
+Now the terminal finally shows kernel boot messages. Although it ends with:
+
+```
+panic - not syncing: No working init found
+```
+
+we have successfully booted the kernel and verified output is working.
+
+To fix this panic, you need to provide a valid `init` process (e.g., `systemd` or `busybox`). This will not be covered in this post.
+
+If you want to reset your kernel configuration to a clean tinyconfig state for further experiments, use:
+
+```bash
+make mrproper
+```
+
+## References
+
+* [Building a tiny Linux from scratch](https://blinry.org/tiny-linux/)