For the case of blkfront drives, there appears to be no difference
between /dev/sda1 and /dev/xvda: the drive always appears as the
kernel device /dev/xvda.
For the case of nvme drives, the root device typically appears as
/dev/nvme0n1. Amazon provides the 'ec2-utils' package for their first
party linux ("Amazon Linux"), which configures udev to create symlinks
from the provided name to the nvme device name. This name is
communicated through nvme "Identify Controller" response, which can be
inspected with:
nvme id-ctrl --raw-binary /dev/nvme0n1 | cut -c3073-3104 | hexdump -C
On Amazon Linux, where the device is attached as "/dev/xvda", this
creates:
- /dev/xvda -> nvme0n1
- /dev/xvda1 -> nvme0n1p1
On NixOS where the device is attach as "/dev/sda1", this creates:
- /dev/sda1 -> nvme0n1
- /dev/sda11 -> nvme0n1p1
This is odd, but not inherently a problem.
NixOS unconditionally configures grub to install to `/dev/xvda`, which
fails on an instance using nvme storage. With the root device name set
to xvda, both blkfront and nvme drives are accessible as /dev/xvda,
either directly or by symlink.
The recent custom endpoint addition allows us to directly point
certbot to the custom Pebble directory endpoint.
Thanks to that, we can ditch the Pebble patch we were using so far;
making this test maintenance easier.
Add a new option permitting to point certbot to an ACME Directory
Resource URI other than Let's Encrypt production/staging one.
In the meantime, we are deprecating the now useless Let's Encrypt
production flag.
- spawn the geoclue-agent directly instead of running it via bash
- document why we cannot use DynamicUser = true
- have systemd create the home directory instead of using an explicit
tmpfiles.d fragment
* lm_sensors: add fancontrol module + nixos test
fancontrol is a small script that checks temperature sensors and adapts
fan speeds accordingly. It reads a text config file that can be
auto-generated by running the pwmconfig wizard on the live system.
Both options were introduced in systemd v243[1]. Those options can be
used to ensure that LinkLocalAddressing is only configured for a given
interface if DHCPv4 fails. To quote `systemd.network(5)`:
```
If "fallback" or "ipv4-fallback" is specified, then an IPv4
link-local address is configured only when DHCPv4 fails. If "fallback", an IPv6 link-local
address is always configured, and if "ipv4-fallback", the address is not configured. Note
that, the fallback mechanism works only when DHCPv4 client is enabled, that is, it requires
"DHCP=yes" or "DHCP=ipv4".
```
[1] 8bc17bb3f7
Default behavior is to continue executing the script even when one or
multiple steps fail. We want to abort early if any part of the
initialization fails to not run with a partially initialized state.
Default behavior also allows dereferencing non-existent variables,
potentially resulting in hard-to-find bugs.
