The Spark Getting Started guide is pretty good, but it’s not immediately obvious that your don’t run your app using Spark API as a standalone executable app. If you try, you’ll get an error like this:
17/11/07 19:15:20 ERROR SparkContext: Error initializing SparkContext.
org.apache.spark.SparkException: A master URL must be set in your configuration
Instead, if using Maven, package the app with ‘mvn package’, start a local master node:
and then you submit it to your Spark node for processing:
--class "MyApp" \
--master local \
This is my first experience running ESXi, and i installed the latest 6.5 version. I’ve been setting up a number of VMs but started to get annoyed with this error when logging on:
Searching around I found this post, which rather aptly claims “Here goes maybe the least impressive work around of all time”. If you’re interested I’ll let go read the other post to find out the amazing workaround 🙂
My 15″ 2012 MacBook Pro started to get unreliable in the past couple of months, with random kernel panic reboots and the ominous “Your computer restarted because of an issue“. Looking in the Console app at the error logs, there were a number of common errors, mainly with the Intel HD graphics. It’s clear something was starting to fail, as having this MacBook Pro as my daily driver for 5 years I’d gone from not rebooting for months (I’d just sleep it over night), to having a random hang then reboot once every couple of weeks, and it started to get more frequent.
Long story short, upgrading to High Sierra was the first OS X or MacOS upgrade that I’d experienced a failure during the install (I’ve gone through 10.5 Leopard, through 10.12 Sierra). I had two disks in this MBP, one SSD and one HDD. Installing High Sierra to my SSD, apparently High Sierra upgrades SSDs by default to the new APFS file system, which is only supported on High Sierra, and apparently is not reversible back to HFS+. So I ended up with a 5 year old machine with a failed upgrade and would boot to a black screen with a spinning progress circle and not get any further. Booting from my second drive which had El Cap on it, it couldn’t see the now APFS drive, and then also started crashing on startup where previously was fine. i spent far too long trying to reinstall a fresh install of El Cap and Sierra and couldn’t get back to a stable place. Even when I did get El Cap cleanly installed, it would crash after a couple of minutes after logging on, so clearly the time had come for this 5 year old machine to be retired.
So, new 15″ 2015 Macbook Pro. Externally it looks very similar to the 2012, with a few minor differences:
- It’s slightly smaller
- It’s thiner
- Noticeably lighter
- The front cutaway section when you insert your thumb to open the screen is not as deep and doesn’t have edges as sharp (which I always thought was weird on the the 2012)
More significant changes:
- The Retina screen is INCREDIBLE. I don’t think I’ve ever seen a screen that is so sharp. Text is incredibly sharp and clear in all apps, and the level of detail even in the stock background images is mindblowing
- The keyboard style is noticeably different. The travel on the keys is much shorter and softer, even squidgy. At first I’d describe the feel as what my 2012 keyboard feels like now it’s well worn after 5 years of daily usage, but after a few days of using it, it feels good for typing, as with less resistance and travel, there’s less need to really mash the keys. I’m not sure if the 2015 has the new butterfly style keys, but either way, a very noticeable change
- It runs cold to the touch, even after being on for a few hours (my 2012 would get warm, and even hot if you were doing something intensive like editing a video)
The single most impressive change that actually prompted me to write this short review is the new touchpad. I could not put my finger on (pun intended) what was different with the touchpad and how it felt. At first I thought it was similar to the shorter, lighter travel of the keys, in that maybe the travel of the touchpad when you click it had been reduced. I did a quick search to read about what had changed, and then it clicked (ha!). The haptic feedback from the touchpad really does feel like it’s clicking, but without the physical movement it feels a bit odd. I’m not sure at this point if it’s better than before, but it’s definitely interesting and a very clever approach. I understand this was a design change to allow the thiner/lighter MacBooks and MacBook Airs to be even thinner without a touchpad that physically moved. Anyway, it was a lightbulb moment when I read about the haptic feedback.
So far, very impressed and pleased with my new machine. I hope that this one too will last another 5 years 🙂