How Do You Know If Your Linux Server Can Support a Docker Installation?

Problem scenario
You want to install Docker on Linux.  How do you determine if the VM or physical server with Linux meets the minimum requirements for installing Docker?

Run this script:

# Written by
echo “This will test if your Linux server is ready for Docker.”

os=$(uname -m | grep -i x)
if [ -z “$os” ];

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How Do You Know If Your Linux Kernel Meets the Minimum Requirements for Docker?

Problem scenario
You want to install Docker, but you want to be sure that the kernel is high enough to be supported.

The minimum kernel version is stated on Docker’s website.  As the spring time of 2017, run this script to find out if your kernel version is high enough:

a=$(uname -r)
b=$(echo $a | awk -F  “.” ‘/1/ {print $1}’)
c=$(echo $a | awk -F 

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How Do You Get Passed an Error about an Environment Variable When Installing etcd on Linux?

Problem scneario
According to, etcd is  “[a] distributed, reliable key-value store” to be used on  “a distributed system.”  You are trying to install etcd, but you get an error about an environment variable and invalid syntax.  

For example, you try to run this script:

But you get this output:  

“2017-03-31 19:22:19.332257 I | flags: recognized and used environment variable ETCD_VERSION=2.2.0
2017-03-31 19:22:19.332385 C | etcdmain: invalid value “2.2.0” for ETCD_VERSION: strconv.ParseBool: parsing “2.2.0”: invalid syntax”

What should you do to install 

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How Do You Determine a MAC Address of an IoT Device (without Network Administrator Access to a Router)?

Problem scenario
You have a device (e.g., some IoT gadget such as an EZviz camera) that can connect to a network (e.g., via WiFi).  But you do not have access to the administration (e.g., back end) of the router itself. You want to learn the IoT device’s MAC address (e.g., for a third party that can grant the device WiFi access).  If you administered the router, you could find the MAC address of devices that could connect to the router.  

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How Do You Configure an Ezviz Mini 0 Camera for the First Time?

Problem Scenario
You want to configure an Ezviz Mini 0 camera for the first time.  How do you set it up?

Warning:  The lowest cost plan for ezviz cloud storage is $59.99.  However you do not have to purchase the cloud storage to use the camera.

1.  Connect the camera to a power outlet.  
2.  Hold the reset button for 10 seconds.

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How Do You Protect Your Privacy When You Are Traveling?

Updated on 1/1/18

Problem scenario
You want to travel and protect your privacy.  You use a cell phone, smart phone, and/or laptop like anyone else.  What can you do to enhance or preserve your privacy?

There are three parts to this solution.  The first part involves items you would bring with you.  The second part is for items that help secure your home when you are away. 

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How Do You Check If a Variable in Ruby Is a Boolean?

Problem scenario
You want to determine if a variable is being assigned a non-string “true” or “false” data type.  That is, you want to distinguish from a string value of true/false and the Boolean, built-in, supported data type of true/false.  Some programming languages support Boolean or bit values.  Ruby has a number of data types.  There is a feature that Ruby supports to test for most of its datatypes.  By appending to a variable this “.is_a?”,

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How Do You Troubleshoot a CentOS Server Not Being Able to Reach the Internet or outside Your Network?

Problem scenario:  From a CentOS server, you try to ping an IP address outside of your network (e.g.,  You get “connect: Network is unreachable” as the response.  Your server has an IP address and subnet mask.  What is wrong?

1.  Ensure that the network has a default gateway.  If the network equipment that connects the server to the network has no gateway to outside the network,

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A List of Apache Spark Books

99 Apache Spark Interview Questions for Professionals by Yogesh Kumar
Advanced Analytics with Spark: Patterns for Learning from Data at Scale by Juliet Hougland, Uri Laserson, Sean Owen, Sandy Ryza and Josh Wills
Apache Spark 2 for Beginners by Rajanarayanan Thottuvaikkatumana
Apache Spark in 24 Hours, Sams Teach Yourself by Jeffrey Aven
Apache Spark for Data Science Cookbook by Padma Priya Chitturi
Apache Spark for Java Developers by Sumit Kumar and Sourav Gulati
Apache Spark Graph Processing by Rindra Ramamonjison
Apache Spark Interview Question &

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How Do You Test If a Variable Is a String or a Numeric Data Type in Ruby?

Problem scenario
You want to test if a given variable is a Numeric or String.  These are built-in data types that Ruby has.

What should you do?

Append “.is_a? Numeric” or “.is_a? String” to variable.  For an example, here is code that explicitly prints out if the data type is a Numeric or String.

var1 = 123
an = var1.is_a? Numeric
as = var1.is_a?

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