nixpkgs/nixos/modules/services/misc/amazon-ssm-agent.nix
Graham Christensen 7547a1f5f8
amazon-ssm-agent: add the system's software to the path
Follow up to #342584.

Similarly to that PR, it is surprising that software which was installed by the user isn't available to a script run over ssm by default.

When executing commands with ssm, users will now have more predictable access to baked-in software instead of an extremely bare-minimum set currently there.
2024-09-18 23:18:28 -04:00

77 lines
2.5 KiB
Nix

{ config, pkgs, lib, ... }:
let
cfg = config.services.amazon-ssm-agent;
# The SSM agent doesn't pay attention to our /etc/os-release yet, and the lsb-release tool
# in nixpkgs doesn't seem to work properly on NixOS, so let's just fake the two fields SSM
# looks for. See https://github.com/aws/amazon-ssm-agent/issues/38 for upstream fix.
fake-lsb-release = pkgs.writeScriptBin "lsb_release" ''
#!${pkgs.runtimeShell}
case "$1" in
-i) echo "nixos";;
-r) echo "${config.system.nixos.version}";;
esac
'';
sudoRule = {
users = [ "ssm-user" ];
commands = [ { command = "ALL"; options = [ "NOPASSWD" ]; } ];
};
in {
imports = [
(lib.mkRenamedOptionModule [ "services" "ssm-agent" "enable" ] [ "services" "amazon-ssm-agent" "enable" ])
(lib.mkRenamedOptionModule [ "services" "ssm-agent" "package" ] [ "services" "amazon-ssm-agent" "package" ])
];
options.services.amazon-ssm-agent = {
enable = lib.mkEnableOption "Amazon SSM agent";
package = lib.mkPackageOption pkgs "amazon-ssm-agent" {};
};
config = lib.mkIf cfg.enable {
# See https://github.com/aws/amazon-ssm-agent/blob/mainline/packaging/linux/amazon-ssm-agent.service
systemd.services.amazon-ssm-agent = {
inherit (cfg.package.meta) description;
wants = [ "network-online.target" ];
after = [ "network-online.target" ];
wantedBy = [ "multi-user.target" ];
path = [
fake-lsb-release
pkgs.coreutils
"/run/wrappers"
"/run/current-system/sw"
];
serviceConfig = {
ExecStart = "${cfg.package}/bin/amazon-ssm-agent";
KillMode = "process";
# We want this restating pretty frequently. It could be our only means
# of accessing the instance.
Restart = "always";
RestartPreventExitStatus = 194;
RestartSec = "90";
};
};
# Add user that Session Manager needs, and give it sudo.
# This is consistent with Amazon Linux 2 images.
security.sudo.extraRules = [ sudoRule ];
security.sudo-rs.extraRules = [ sudoRule ];
# On Amazon Linux 2 images, the ssm-user user is pretty much a
# normal user with its own group. We do the same.
users.groups.ssm-user = {};
users.users.ssm-user = {
isNormalUser = true;
group = "ssm-user";
};
environment.etc."amazon/ssm/seelog.xml".source = "${cfg.package}/etc/amazon/ssm/seelog.xml.template";
environment.etc."amazon/ssm/amazon-ssm-agent.json".source = "${cfg.package}/etc/amazon/ssm/amazon-ssm-agent.json.template";
};
}