Quantcast File System 1.2 for ARM71

I have been using the Quantcast File System (QFS) as my primary distributed file system on my ODROID XU4 cluster.  Due to QFS’s low memory footprint. it works well with Spark, allowing me to assign as much of the ODROID XU4’s limited 2 GB RAM footprint to the Spark executor running on a node. Recently, QFS 1.2 was released. This version brings many features and updates, many not relevant to my ODROID cluster use case. However, the most notable updates relevant to the ODROID XU4 cluster include: Correct Spark’s ability to create a hive megastore on a new QFS instance (QFS-332) Improved error reporting in the QFS/HDFS shim HDFS shim for the Hadoop 2.7.2 API, which the latest versions of Spark use. In this post, I will update the ODROID XU4 cluster to use QFS 1.2.0. I have also updated my original post on using QFS with Spark, which you should use if you are starting from scratch. Install  QFS 1.2 cd /opt Read More …

Adding a New Node to the ODROID XU4 Cluster

I recently acquired another ODROID XU4 device (and a MicroSD card for bulk storage) to add it to my XU4 cluster. This new node brings my node count to five. Adding a new node to the cluster is relatively straight forward, but there are a lot of details. In the modern datacenter, this operation would be accomplished through a package manager, which would build the new node according to an image. However, I haven’t set up package management on my cluster so I will need to sit up the new node manually. In the original cluster configuration, I used a 5-port ethernet switch for the internal network. Given that there was an open port, no additional hardware beyond the new node is needed. However, if I were to add a sixth node (or beyond), I would need to update my ethernet switch to something such as an 8-port switch. I will also note that using the 40 mm PCB spacers I originally ordered makes Read More …

Connecting to HDFS from an computer external to the cluster

Since I have set up my ODROID XU4 cluster to work with Spark from a Jupyter web notebook, one of the little annoyances I have had is how inefficient it was to transferring data into the HDFS file system on the cluster.  It involved downloading data to my Mac laptop via a web download, transferring that data to the master node, then running hdfs dfs -put  to place the data onto the file system. While I did set up my cluster to create an NFS mount, it can be very slow when transferring large files to HDFS. So, my solution to this was to install HDFS on my Mac laptop, and configure it to use the ODROID XU4 cluster. One of the requirements for an external client (e.g., your Mac laptop) to interact with HDFS on a cluster is that the external client must be able to connect to every node in the cluster. Since the master node of the cluster was Read More …

Mounting HDFS with NFS

After setting up the Hadoop installation on the ODROID XU4 cluster, we need to find a way to get data in and out of it. The traditional pattern used when a cluster is on it’s own network such as ours is is to have an edge node where the user logs into, transfers the data to that edge node, then put that data in HDFS from the edge node. Speaking from experience, this is annoyingly to much work. For my personal cluster, I want the HDFS file system to integrate with my Mac laptop. The most robust way to accomplish my goal with HDFS is to have it mounted as a NFS drive. The Hadoop distribution we are using has a NFS server built in. This server is run on the master node, effectively acting as a proxy between the HDFS cluster and the external network. The pros to this approach is that I get the usage paradigm that I want. Read More …

Installing Hadoop onto an ODROID XU4 Cluster

Now is the time when we start to see the fruits of our labor in getting the ODROID XU4 low cost cluster built. We will be installing Hadoop and configuring it to serve an NFS mount that can be mounted on your client computer (e.g., your laptop) to be able to interact with the HDFS file system as if it were another hard drive on your computer. This feature will greatly ease the use of our cluster, as it will minimize the need for a user to log into the cluster to use it. An NFS mount is not the only necessary facet of the cluster to enable the client usage vision, but it is an important one. Before we install Hadoop, let’s discuss what we are trying to accomplish by installing it. Hadoop has three components: the Hadoop File System (HDFS), Yarn, and Map-Reduce. For our purposes, we are most interested in HDFS, but we will play around with the Read More …

Adding the MicroSD Data Drives to the ODROID XU4 Cluster

We are nearly done with the basic set up of the ODROID XU4 four node cluster. The final step is to configure the MicroSD cards that were in the bill of materials as data drives for each node. Before we start, ensure that the cluster is completely powered down and remove the power cords from each node. We will be removing and adding components to the ODROID XU4’s, and it is just best practice to have no power to the device when removing or adding components. The first step is to format each MicroSD card with the ext4 filesystem. Each platform has it’s own instructions for how to do this. I will provide the Mac OS X instructions since that is what I use. In the terminal, do the following: If you don’t have it already, install the Homebrew package management app for OS X. Visit the brew.sh website for instructions. Install the e2fsprogs utility using brew install e2fsprogs With the MicroSD card attached to your computer, Read More …

Configuring the ODROID XU4 Operating System

UPDATE – This post was originally written for HardKernel’s distribution of Ubuntu 15.10, but now has been changed to use the ODROID server image for Ubuntu 14.04 LTS, which is available from HardKernel here. The motivation for this change was to use an official HardKernel support distribution that was specifically built for headless server application. Ubuntu 14.04 LTS may be an older distribution, but it works for our purposes. Temporary Networking Setup When setting up the nodes initially, you will need to SSH into them to configure their settings. However, if we go straight to our network design, we will not be able to connect to any node between the master node is not yet set up as a router. So we will need to connect each node directly to the external network (e.g., you home network). Since the bill of materials called for a 5-port ethernet switch and there are only 4 nodes, we will start by having the external network Read More …

Building the ODROID XU4 Low Cost Cluster

My shipment of ODROID XU4s that I ordered for my low cost cluster came into today. So I set out to assemble the cluster. My daughter “helped” me with this, making it a fun family activity. First thing I did was layout the nodes. Though I knew these board would be small, it did impress me just how small they were. The first task is to attach the eMMC drive to each node. Note that I eventually had to undo this as I later discovered I needed to flash the drives with the latest Ubuntu build. But given the amount of space the PCB standoffs five, removing and reattaching the eMMC drive is not hard. Then I attached the XU4s together with the PCB standoffs I bought. The short standoffs are for the “feet” to the stack, and the long ones to separate each node. Once I stacked all of the nodes, I attached the ethernet switch and the cabling. I Read More …