nixos-infect/README.md

# NixOS-Infect

## What is this?
A script to install NixOS on non-NixOS hosts.

NixOS-Infect is so named because of the high likelihood of rendering a system inoperable.
Use with extreme caution and preferably only on newly provisioned systems.

This script has successfully been tested on at least the follow hosting providers and plans:

* [DigitalOcean](https://www.digitalocean.com/products/droplets/)
* [Hetzner Cloud](https://www.hetzner.com/cloud)
* [Vultr](https://www.vultr.com/)
* [Interserver VPS](https://www.interserver.net/vps/)
* [Tencent Cloud Lighthouse](https://cloud.tencent.com/product/lighthouse)
* [OVHcloud](https://www.ovh.com/)

Should you find that it works on your hoster,
feel free to update this README and issue a pull request.

> *NB:* OpenVZ-based virtualization providers are known not to work with `nixos-infect` (or any other OS takeover script).
> This is core to how OpenVZ operates and cannot be resolved.

## Motivation

Motivation for this script: nixos-assimilate should supplant this script entirely,
if it's ever completed.
nixos-in-place was quite broken when I tried it,
and also took a pretty janky approach that was substantially more complex than this
(although it supported more platforms):
it didn't install to root (/nixos instead),
left dregs of the old filesystem
(almost always unnecessary since starting from a fresh deployment),
and most importantly, simply didn't work for me!
(old system was being because grub wasnt properly reinstalled)

## How do I use it?

0) **Read and understand the [the script](./nixos-infect)**
1) Deploy any custom configuration you want on your host
2) Deploy your host as non-Nix Operating System.
3) Deploy an SSH key for the root user.

> *NB:* This step is important.
> The root user will not have a password when nixos-infect runs to completion.
> To enable root login, you *must* have an SSH key configured.

4) run the script with:
```
  curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | NIX_CHANNEL=nixos-20.09 bash -x
```

*NB*: This script wipes out the targeted host's root filesystem when it runs to completion.
Any errors halt execution.
A failure will leave the system in an inconsistent state,
and so it is advised to run with `bash -x`.

## Hoster notes:
### Digital Ocean
You mmay utilize Digital Ocean's "user data" mechanism (found in the Web UI or HTTP API),
and supply to it the following example yaml stanzas:

```yaml
#cloud-config

runcmd:
  - curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | PROVIDER=digitalocean NIX_CHANNEL=nixos-20.09 bash 2>&1 | tee /tmp/infect.log
```

#### Potential tweaks:
- `/etc/nixos/{,hardware-}configuration.nix`: rudimentary mostly static config
- `/etc/nixos/networking.nix`: networking settings determined at runtime tweak if no ipv6, different number of adapters, etc.

```yaml
#cloud-config
write_files:
- path: /etc/nixos/host.nix
  permissions: '0644'
  content: |
    {pkgs, ...}:
    {
      environment.systemPackages = with pkgs; [ vim ];
    }
runcmd:
  - curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | PROVIDER=digitalocean NIXOS_IMPORT=./host.nix NIX_CHANNEL=nixos-20.09 bash 2>&1 | tee /tmp/infect.log
```


#### Tested on
|Distribution|       Name      | Status    | test date|
|------------|-----------------|-----------|----------|
|CentOS      |6.9 x32          | _failure_ |2020-03-30|
|CentOS      |6.9 x64          | _failure_ |2020-03-30|
|CentOS      |7.6 x64          | _failure_ |2020-03-30|
|CentOS      |8.1 x64          |**success**|2020-03-30|
|CoreOS      |2345.3.0 (stable)| _unable_  |2020-03-30|
|CoreOS      |2411.1.0 (beta)  | _unable_  |2020-03-30|
|CoreOS      |2430.0.0 (alpha) | _unable_  |2020-03-30|
|Debian      |10.3 x64         |**success**|2020-03-30|
|Debian      |9.12 x64         |**success**|2020-03-30|
|Fedora      |30 x64           |**success**|2020-03-30|
|Fedora      |31 x64           |**success**|2020-03-30|
|FreeBSD     |11.3 x64 ufs     | _failure_ |2020-03-30|
|FreeBSD     |11.3 x64 zfs     | _failure_ |2020-03-30|
|FreeBSD     |12.1 x64 ufs     | _failure_ |2020-03-30|
|FreeBSD     |12.1 x64 zfs     | _failure_ |2020-03-30|
|RancherOS   |v1.5.5           | _unable_  |2020-03-30|
|Ubuntu      |16.04.6 (LTS) x32|**success**|2020-03-30|
|Ubuntu      |16.04.6 (LTS) x64|**success**|2020-03-30|
|Ubuntu      |18.04.3 (LTS) x64|**success**|2020-03-30|
|Ubuntu      |19.10 x64        |**success**|2020-03-30|

### Vultr

To set up a NixOS Vultr server,
instantiate an Ubuntu box with the following "Startup Script":

```bash
#!/bin/sh

curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | NIX_CHANNEL=nixos-20.09 bash
```

Allow for a few minutes over the usual Ubuntu deployment time for NixOS to download & install itself.

#### Tested on
|Distribution|       Name      | Status    | test date|   Slug           |   ID    |
|------------|-----------------|-----------|----------|------------------|---------|
| Ubuntu     | 18.10 x64       |**success**|(Unknown) | (Unknown)        |(Unknown)|


### Hetzner cloud

Hetzner cloud works out of the box.
When creating a server provide the following script as "User data":

```
#!/bin/sh

curl https://raw.githubusercontent.com/elitak/nixos-infect/master/nixos-infect | NIX_CHANNEL=nixos-20.09 bash 2>&1 | tee /tmp/infect.log
```

#### Tested on
|Distribution|       Name      | Status    | test date|
|------------|-----------------|-----------|----------|
|Ubuntu      | 20.04 x64       |**success**|(Unknown) |

### InterServer VPS
#### Tested on
|Distribution|       Name      | Status    | test date|
|------------|-----------------|-----------|----------|
|Debian      | 9               |**success**|2021-01-29|
|Debian      | 10              |**success**|2021-01-29|
|Ubuntu      | 20.04           |**success**|2021-01-29|
|Ubuntu      | 18.04           |**success**|2021-01-29|
|Ubuntu      | 14.04           |**success**|2021-01-29|


### Tencent Cloud Lighthouse

Tencent Cloud Lighthouse **Hong Kong** Region Works out of the box.

Other Regions in China may not work because of the unreliable connection between China and global Internet or [GFW](https://en.wikipedia.org/wiki/Great_Firewall).

#### Tested on
|Distribution|       Name      | Status    | test date|
|------------|-----------------|-----------|----------|
|Debian      | 10              |**success**|2021-03-11|


### OVHcloud

Before executing the install script, you may need to check your mounts with `df -h`. By default, OVH adds a relatively short in memory `tmpfs` mount on the `/tmp` folder, so the install script runs short in memory and fails. Just execute `umount /tmp` before launching the install script. Full install process described [here](https://lyderic.origenial.fr/install-nixos-on-ovh)

|Distribution|       Name        | Status    | test date|
|------------|-------------------|-----------|----------|
|Arch Linux  | Arch Linux x86-64 |**success**|2021-03-25|