+++
title = "My server is now a virtual machine"
author = ["Michał Sapka"]
date = 2024-09-26T21:29:00+02:00
categories = ["blog"]
draft = false
weight = 2001
image_dir = "blog/images"
image_max_width = 600
abstract = "Memoir from a forced migation"
listening = "Steve Kirk -  Thimbleweed Park (Original Soundtrack)"
listening_url = "https://thimbleweedpark.bandcamp.com/album/thimbleweed-park-original-soundtrack"
listening_img = "steve-kirk-thimbleweed-park.jpg"
+++

The unthinkable has happened - and by that, I mean it was a matter of time, but I wasn't expecting a week.
The SD card used in Raspberry Pi behind [crys.site](https://crys.site) got corrupted beyond fixing.
I tried, tried (I gave it good 30 mins) and failed.
Super block was borked, fixing the filesystem was impossible.

But I will not let go of my FreeBSD server!
_Beastie or Bust!_.
I have this quite modern Synology, so why not use it?
The UI is not for me, but I can set up a virtual machine there and boom - everything will be all right with the world.
On the host FreeBSD all I had to do was:

-   enable sshd(8)
-   install doas(1)

And add a bridge to the network, which will be used by the jails:

```shell
# /etc/rc.conf

cloned_interfaces="bridge0"
ifconfig_bridge0="addm em0 up"
kld_list="if_bridge if_epair"
```

The SD card used UFS (default image for FreeBSD on Raspberry), so I lost it.
But all my data, the sites and jails were stored on external thumb drive in a ZFS pool.
This made the transition incredibly fast.
First, I had to create a recursive (`-r`) snapshot of the root dataset.
I found naming it `fun` funny.

```shell
zfs snapsot -r extdata@fin
```

And I was able to transfer all descendant datasets to to the new machine

```shell
zfs send -R extdata/jail@fin | ssh 10.0.7.0 zfs recv zroot/jail
```

Oh ZFS, we don't deserve you.

Then I recreated my jail.conf[^fn:1] with DHCP VNET:

```shell
# STARTUP/LOGGING
exec.clean;
exec.start = "/bin/sh /etc/rc";
exec.stop = "/bin/sh /etc/rc.shutdown";
exec.consolelog = "/var/log/jail_console_${name}.log";

# PERMISSIONS
allow.raw_sockets;
exec.clean;
mount.devfs;
devfs_ruleset = 5;
vnet;
allow.raw_sockets = 1;

host.hostname = "${name}.dune.local";
path = "/usr/local/jails/containers/${name}";
$epair = "epair${id}";
$bridge = "bridge0";
vnet.interface = "${epair}b";

exec.start += "dhclient ${epair}b";
exec.prestart  = "/sbin/ifconfig ${epair} create up";
exec.prestart += "/sbin/ifconfig ${epair}a up descr jail:${name}";
exec.prestart += "/sbin/ifconfig ${bridge} addm ${epair}a up";

exec.poststop = "/sbin/ifconfig ${bridge} deletem ${epair}a";
exec.poststop += "/sbin/ifconfig ${epair}a destroy";

nginx {
  $id=1;
}

sites {
  $id=10;
}
```

and... nothing.
Nada.
The jails won't start.

Raspberry Pi is ARM, my VM is x86.
I had to create new jails - which is a breeze thanks to, again, ZFS.
Since jails are normal directories, I was able to simply copy configs to new jails.
In all, this forced migration took 2 hours.
And that includes downloading data.

Emacs made it very easy, since I can use `tramp` with `doas` to edit remote files as root:

```shell
/sshx:mms@10.0.7.0|doas::
```

The last missing puzzle was strange change from RPI, as jail's Mac addresses started changing after each start.
Luckily, BSD is a community so [meka](https://bsd.network/@meka) provided me with config to force Mac address for jail, and I've added:

```shell
exec.prestart += "/sbin/ifconfig ${epair}b ether ${mac}";
```

Truly, FreeBSD is a gift that keeps on giving.

[^fn:1]: This config is a combination of what [Ruben](https://rubenerd.com/starting-with-freebsd-jails/), [FreeBSD Guides](https://docs.freebsd.org/en/books/handbook/jails/), and [FreeBSD Wiki](https://wiki.freebsd.org/Jails) has thought me.
    I'll need to step up and buy [Jail Mastery](https://mwl.io/nonfiction/os#fmjail) book from MWL sometime in the near future.