nh2

I believe the following is the best way to work with Nagle's algorithm / TCP_NODELAY / TCP_CORK.

It is described in this RedHat manual and the verdict is:

• Set TCP_NODELAY = 1, always.
• If you can batch data for sending by creating a buffer manually, or using writev(), prefer that.
• If you cannot (e.g. "when using different libraries that provides abstractions for layers" from the above manual):
  • Set TCP_CORK = 1, then write the data, then set TCP_CORK = 0.
• This builds a packet in kernel space and then flushes it out.

nh2

import numpy as np
import numpy.linalg

# Relevant links:
#   - http://stackoverflow.com/a/32244818/263061 (solution with scale)
#   - "Least-Squares Rigid Motion Using SVD" (no scale but easy proofs and explains how weights could be added)


# Rigidly (+scale) aligns two point clouds with know point-to-point correspondences
# with least-squares error.

nh2

-- Shows how to implement an `instance Eq` for a GADT wrapped in an existential type.

{-# LANGUAGE GADTs #-}
{-# LANGUAGE StandaloneDeriving #-}
{-# LANGUAGE ExistentialQuantification #-}
{-# LANGUAGE TypeOperators #-}

import Data.Type.Equality

-- | A GADT. The example would also work if it had more than 1 type parameter.

nh2

# Build with:
#     NIX_PATH=nixpkgs=$HOME/src/nixpkgs nix-build --no-link '<nixpkgs/nixos>' -A config.system.build.tarball -I nixos-config=thisfile.nix
# You can also use
#     -A config.system.build.toplevel
# to build something you can browse locally (that uses symlinks into your nix store).

{config, pkgs, ...}:
{
  # We need no bootloader, because the Chromebook can't use that anyway.
  boot.loader.grub.enable = false;

nh2

(bootloader) product:sunfish
(bootloader) serialno:17191JEC203691
(bootloader) variant:SM7 UFS
(bootloader) max-download-size:0x10000000
(bootloader) slot-suffixes:_a,_b
(bootloader) version-bootloader:s5-0.5-10252351
(bootloader) version-baseband:g7150-00112-230505-B-10075601
(bootloader) secure-boot:PRODUCTION
(bootloader) secure:yes
(bootloader) hw-revision:MP1.0

nh2

How to determine if the nix sandbox is in effect on a system

Do the same as the nix-info script, which nix-builds this file and inspects the exit code.

Short version:

nix-build --no-out-link -E 'import <nixpkgs/pkgs/tools/nix/info/multiuser.nix>' 2> /dev/null

nh2

{ config, lib, pkgs, ... }:

with lib;

let
  cfg = config.services.ceph-benaco;

  inherit (pkgs.callPackage ../helpers.nix {}) ensureUnitExists;
in

nh2

#!/usr/bin/env bash

# Installs NixOS on an OVH server, wiping the server.
#
# This is for a specific server configuration; adjust where needed.
# Originally written for an OVH STOR-1 server.
#
# Prerequisites:
#   * Create a LUKS key file at /root/benacofs-luks-key
#     e.g. by copying it up.

nh2

#!/usr/bin/env python3

# How to use:
#
# Ubuntu 16.04: apt install -y python-boto OR apt install -y python3-boto
#
# Specify the default profile on aws/boto profile files or use the optional AWS_PROFILE env var:
# AWS_PROFILE=example ./dehydrated -c -d example.com -t dns-01 -k /etc/dehydrated/hooks/route53.py
#
# Manually specify hosted zone:

nh2

GlusterFS SSL setup tutorial

Following:

• http://gluster.readthedocs.io/en/latest/Administrator%20Guide/SSL/
• https://access.redhat.com/documentation/en-US/Red_Hat_Storage/3.1/html/Administration_Guide/chap-Network_Encryption.html

I use GlusterFS 3.9 here.

Prerequisites