43 lines
2.3 KiB
Markdown
43 lines
2.3 KiB
Markdown
# nixos-images
|
|
|
|
Automatically weekly updated images for NixOS. This project is intended to extend the images created by hydra.nixos.org.
|
|
We are currently creating the images listed below:
|
|
|
|
## Netboot images
|
|
|
|
You can boot the netboot image using this [ipxe script](https://github.com/nix-community/nixos-images/releases/download/nixos-unstable/netboot-x86_64-linux.ipxe).
|
|
It consists of the [kernel image](https://github.com/nix-community/nixos-images/releases/download/nixos-unstable/bzImage-x86_64-linux) and [initrd](https://github.com/nix-community/nixos-images/releases/download/nixos-unstable/bzImage-x86_64-linux).
|
|
|
|
## Kexec tarballs
|
|
|
|
These images are used for unattended remote installation in [nixos-anywhere](https://github.com/numtide/nixos-anywhere).
|
|
|
|
Kexec is a mechanism in Linux to load a new kernel from a running Linux to
|
|
replace the current kernel. This is useful for booting the Nixos installer from
|
|
existing Linux distributions, such as server provider that do not offer a NixOS
|
|
option. After running kexec, the NixOS installer exists only in memory. At the
|
|
time of writing, this requires at least 1.5GB of physical RAM (swap does not
|
|
count) in the system. If not enough RAM is available, the initrd cannot be
|
|
loaded. Because the NixOS runs only in RAM, users can reformat all the system's
|
|
discs to prepare for a new NixOS installation.
|
|
|
|
It can be booted as follows by running these commands as root:
|
|
|
|
```
|
|
curl -L https://github.com/nix-community/nixos-images/releases/download/nixos-unstable/nixos-kexec-installer-noninteractive-x86_64-linux.tar.gz | tar -xzf- -C /root
|
|
/root/kexec/run
|
|
```
|
|
|
|
The kexec installer comes with the following features:
|
|
|
|
- Re-uses ssh host keys from the sshd to not break `.ssh/known_hosts`
|
|
- Authorized ssh keys are read from `/root/.ssh/authorized_keys`, `/root/.ssh/authorized_keys2` and `/etc/ssh/authorized_keys.d/root`
|
|
- Static ip addresses and routes are restored after reboot.
|
|
Interface that had dynamic addresses before are configured with DHCP and
|
|
to accept prefixes from ipv6 router advertisement
|
|
|
|
|
|
The actual kexec happens with a slight delay (6s). This allows for easier
|
|
integration into automated nixos installation scripts, since you can cleanly
|
|
disconnect from the running machine before the kexec takes place. The tarball
|
|
is also designed to be run from NixOS, which can be useful for new installations
|