• Backup Discourse with External PostgreSQL Server

    Posted on: Sun, 01/21/2018 - 05:58 By: Huahai

    Discourse is a modern forum software that is quite popular in the technology circle. One can install a Discourse server easily with the recommended method of using docker. All the services needed by the Discourse server, e.g. Postgresql and Redis, will be running inside a docker container, which is fine for a small installation. However, if one has already an external Postgresql server running, e.g.

  • FreeIPA in AWS EC2

    Posted on: Thu, 12/07/2017 - 23:34 By: Huahai

    Show how to install and configure freeIPA server and clients in AWS EC2 using Route53. Point out several important issues.

  • Ecobee3 installation with K wire

    Posted on: Fri, 12/01/2017 - 06:13 By: Huahai

    How to install Ecobee3 smart thermostat when one of the existing wire connection is labeled K on the old device? This is problematic because K wire does not appear in the Ecobee3's documentation, nor in the on screen menu. I found a solution: simply connect the K wire to Y1, then enable the G connection on Ecobee3 configuration screen.​

  • Data-Oriented Programming (DOP)

    Posted on: Sat, 12/03/2016 - 23:33 By: Huahai

    JSON is arguably the world's most popular human readable data format today.  It has largely replaced XML as the data exchange format on the Internet. One of the key reasons for the proliferation of JSON is its simplicity.  The data structure are very limited: only arrays, enclosed with []; and objects, enclosed with {}. That's it. It cannot be simpler.

    Apparently, this dead simple data format is enough to represent the vast landscape of data that JSON becomes the de-facto data format for Web services. Most Web APIs we use today speaks JSON. However, JSON is not native for most programming languages. It becomes a pain to convert to and back from JSON in programming languages.

  • 从变量说开来

    Posted on: Wed, 02/25/2015 - 22:07 By: Huahai


    的变量啊”, variable for what? 后来明白了,原来就是一个地址可以存不同的东西啊


    You don't need to *understand* mathematics, you just get used to it". 这种人



  • How to get a kitty manicure

    Posted on: Wed, 09/04/2013 - 06:34 By: Huahai

    Speaker: Tom

    Dear fellow kitties, I am going to show you how to get a kitty manicure and pedicure.

    First of all, let me show you my beautiful finger nails. My mom polishes each and every one of them on a weekly basis. Such weekly pampering is essential for a purrfect kitty like me.

    Now, let me show you how to get a kitty manicure.

    First of all, relax and get each of your finger massaged. I like to sit on my mommy's lap to do the massage, but Mayori prefers to get her massage in her favorite bed.

Subscribe to Huahai's Blog