Netdata

netdata is a metrics tool, which comes with a lot of sane preconfiguration. It contains of various plugins, which need to be enabled sometimes with additional effort.

Adding node

• Install the netdata package and enable the service.
• When adding new node in the web interface you get a token, write that token to /var/lib/netdata/cloud.d/token
• As root run nix-shell -p netdata --run "netdata-claim.sh"

Streaming node setup

Ensure you choose appropriate access control for your nodes.

Receiver node

services.netdata.configDir."stream.conf" =
  let
    mkChildNode = apiKey: allowFrom: ''
      [${apiKey}]
        enabled = yes
        default history = <a value of your choice>
        default memory mode = dbengine # a good default
        health enabled by default = auto
        allow from = ${allowFrom}
    '';
  in pkgs.writeText "stream.conf" ''
    [stream]
      # This won't stream by itself, except if the receiver is a sender too, which is possible in netdata model.
      enabled = no
      enable compression = yes

    # An allowed sender node
    ${mkChildNode "an API key" "an allowed IP"}
  '';

Sender node

services.netdata.configDir."stream.conf" = pkgs.writeText "stream.conf" ''
  [stream]
    enabled = yes
    destination = receiver-hostname-or-ip-address:19999
    api key = any string that is set also on the receiver side
'';

If you don't need any web UI and want to consume minimal resources on the sender node, use:

services.netdata = {
  config = {
    global = { "memory mode" = "none"; };
    web = {
      mode = "none";
      "accept a streaming request every seconds" = 0;
    };
  };
};

This way, it won't spawn any web UI, neither store any metric locally.

Python Plugins

nvidia-smi

To enable the nvidia-smi plugin you have to make sure nvidia-smi can be called by netdata.

systemd.services.enable = true;
systemd.services.netdata.path = [pkgs.linuxPackages.nvidia_x11];
services.netdata.configDir."python.d.conf" = pkgs.writeText "python.d.conf" ''
  nvidia_smi: yes
'';

samba

To enable samba plugin additional permissions and configurations will need to be set.

services.netdata.configDir."python.d.conf" = pkgs.writeText "python.d.conf" ''
  samba: yes
'';

# add samba and sudo to path of python plugin
systemd.services.netdata.path = [  pkgs.samba "/run/wrappers" ];

# permit to run sudo smbstatus -P
security.sudo.extraConfig = ''
  netdata ALL=(root) NOPASSWD: ${pkgs.samba}/bin/smbstatus
'';

# as documented here : https://github.com/netdata/netdata/blob/master/system/netdata.service.in
# review capabilityset above if other plugins are non functional
systemd.services.netdata.serviceConfig.CapabilityBoundingSet = ["CAP_SETGID"];

# enable profiling
services.samba.extraConfig = ''
  smbd profiling level = on
'';