Setting up the DeviceAllow list with explicitly configured devices was a
nice idea, but sometimes a configured device (`/dev/nvme0n1` an NVMe
namespace) has a parent device (`/dev/nvme0`) that smartctl needs to
access to query metrics.
Falling back to the block and character definitions is probably a valid
fallback.
See the discussion below the original PR[1] and #197443 for more
context.
I guess I missed that upon review because the branch was too old and I
cherry-picked the commit onto my deployment branch which is based on
22.05. Sorry for that!
[1] https://github.com/NixOS/nixpkgs/pull/162784#issuecomment-1306848036
Netdev collector needs AF_NETLINK permissions to work. It will fail with
the message "couldn't get netstats: socket: address family is not
supported by protocol" otherwise.
The current `ExecStart` will not allow for multiple sockets to properly
be passed to the program since the extra newline character is interpreted to
be part of the socket path.
conversions were done using https://github.com/pennae/nix-doc-munge
using (probably) rev f34e145 running
nix-doc-munge nixos/**/*.nix
nix-doc-munge --import nixos/**/*.nix
the tool ensures that only changes that could affect the generated
manual *but don't* are committed, other changes require manual review
and are discarded.
this notable also now interprets a markdown-flavored list in
triton_sd_config as actual markdown and renders it differently, but this
is arguably for the better (and probably the original intention).
no other rendering changes.
there seems to be a lot of markdown in the prometheus module that
should've been docbook instead. temporarily convert it to docbook to
keep the diff for the docbook->md conversion of prometheus inspectable.
this renders the same in the manpage and a little more clearly in the
html manual. in the manpage there continues to be no distinction from
regular text, the html manual gets code-type markup (which was probably
the intention for most of these uses anyway).
now nix-doc-munge will not introduce whitespace changes when it replaces
manpage references with the MD equivalent.
no change to the manpage, changes to the HTML manual are whitespace only.
make (almost) all links appear on only a single line, with no
unnecessary whitespace, using double quotes for attributes. this lets us
automatically convert them to markdown easily.
the few remaining links are extremely long link in a gnome module, we'll
come back to those at a later date.
the conversion procedure is simple:
- find all things that look like options, ie calls to either `mkOption`
or `lib.mkOption` that take an attrset. remember the attrset as the
option
- for all options, find a `description` attribute who's value is not a
call to `mdDoc` or `lib.mdDoc`
- textually convert the entire value of the attribute to MD with a few
simple regexes (the set from mdize-module.sh)
- if the change produced a change in the manual output, discard
- if the change kept the manual unchanged, add some text to the
description to make sure we've actually found an option. if the
manual changes this time, keep the converted description
this procedure converts 80% of nixos options to markdown. around 2000
options remain to be inspected, but most of those fail the "does not
change the manual output check": currently the MD conversion process
does not faithfully convert docbook tags like <code> and <package>, so
any option using such tags will not be converted at all.
For reference:
- ./nixos/modules/services/monitoring/grafana.nix
- 80192f1fe3/debian/service
- 5894b9b77a/trunk/prometheus.service
I have omitted the Limit* as they do not appear to be commonly used in
NixOS, and, per `man systemd.exec`, are less preferred vs. cgroup
limits.
The old way of writing the file omited qoutes within strings which are needed by some configurations like federations.
The quotes got lost when `echo`ing the content via `echo '${builtins.toJSON x}'`.
The pkgs.formats.json does handle that race condition properly, so this commit switches the writing to that helper.
Fixes race conditions like this:
> systemd[1]: Started prometheus-kea-exporter.service.
> kea-exporter[927]: Listening on http://0.0.0.0:9547
> kea-exporter[927]: Socket at /run/kea/dhcp4.sock does not exist. Is Kea running?
> systemd[1]: prometheus-kea-exporter.service: Main process exited, code=exited, status=1/FAILURE
When no devices are given the exporter tries to autodiscover available
disks. The previous DevicePolicy was however preventing the exporter
from accessing any device at all, since only explicitly mentioned ones
were allowed.
This commit adds an allow rule for several device classes that I could
find on my machines, that gets set when no devices are explicitly
configured.
There is an existing problem with nvme devices, that expose a character
device at `/dev/nvme0`, and a (namespaced) block device at
`/dev/nvme0n1`. The character device does not come with permissions that
we could give to the exporter without further impacting the hardening.
crw------- 1 root root 247, 0 27. Jan 03:10 /dev/nvme0
brw-rw---- 1 root disk 259, 0 27. Jan 03:10 /dev/nvme0n1
The autodiscovery only finds the character device, which the exporter
unfortunately does not have access to.
However a simple udev rule can be used to resolve this:
services.udev.extraRules = ''
SUBSYSTEM=="nvme", KERNEL=="nvme[0-9]*", GROUP="disk"
'';
Unfortunately I'm not fully aware of the security implications this
change carries and we should question upstream (systemd) why they did
not include such a rule.
The disk group has no members on any of my machines.
❯ getent group disk
disk❌6:
Otherwise, `postfix_up{path="/var/lib/postfix/queue/public/showq"}` will
always be `0` indicating an postfix outage because this is a unix domain
socket that cannot be connected to:
2021/12/03 14:50:46 Failed to scrape showq socket: dial unix /var/lib/postfix/queue/public/showq: socket: address family not supported by protocol
The option `services.prometheus.environmentFile` has been removed since it was causing [issues](https://github.com/NixOS/nixpkgs/issues/126083) and Prometheus now has native support for secret files.
The new option `services.prometheus.enableReload` has been introduced
which, when enabled, causes the prometheus systemd service to reload
when its config file changes.
More specifically the following property holds: switching to a
configuration (`switch-to-configuration`) that changes the prometheus
configuration only finishes successully when prometheus has finished
loading the new configuration.
`enableReload` is `false` by default in which case the old semantics
of restarting the prometheus systemd service are in effect.
9fea6d4c85 broke rtl_433-exporter by
introducing several hardening options which do not play well with
rtl_433 requiring writing to USB. More precisely, rtl_433 requires
(a) AF_NETLINK to configure the radio; (b) access to the USB device,
but PrivateDevices=true hides them; (c) rw access to the USB device,
but DeviceAllow= block-lists everything.
This commit was tested on real hardware with a standard NixOS setup.
The timex collector (enabled by default) needs the
adjtimex syscall, which was disabled by
9fea6d4c85.
So allow it unless the timex collector is disabled.
The systemd collector needs AF_UNIX to talk to
/var/run/dbus/system_bus_socket, which was broken
with 9fea6d4c85.
This commit allows AF_UNIX when needed.
