This artical marked the way we scale up Fabflix to handle massive amounts of traffic by using a cluster of MySQL and Tomcat. Since the user would have only one entry point to Fabflix, then we need to use a load balancer to balance the traffic from one entry point to multiple Fabflix instances.

Step 1 (master/slave):

Create a dummy user for the two example Tomcat applications below:

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shell> mysql -u root -p
mysql> CREATE USER 'mytestuser'@'localhost' IDENTIFIED BY 'mypassword';
mysql> GRANT ALL ON *.* TO 'mytestuser'@'localhost';

Step 2 (master/slave):

Setup Tomcat on each master/slave instance.

Step 3 (master/slave):

On each master/slave instance, deploy TomcatTest.war. Make the URL http://PUBLIC_IP:8080/TomcatTest/servlet/TomcatTest work. You may need to modify the username/password and IP address (use the internal AWS instance address). Also make sure to modify the AWS security group setting for these two instances to allow remote access to their 8080 port.

This artical shows how to setup a MySQL cluster on AWS that includes a master and a slave. Reads can be sent to any of the two instances, and writes have to be sent to the master instance.

1. Setup two new AWS instances:

• Create two new AWS instances identical to your previous instance used to run Fabflix. We call these “instance 2” (as the master) and “instance 3”‘ (as the slave). We assume their public IPs are 2.2.2.2 and 3.3.3.3, and their internal AWS IPs are 172.2.2.2 and 172.3.3.3, respectively.

• Add new rules in their security group(s) to open their MYSQL/Aurora type to each other using their AWS internal IP.

2. Set up the master instance.

• SSH to the master instance. Run the following command to install MySQL server.

  1 2	master-shell> sudo apt-get update master-shell> sudo apt-get install mysql-server

• Edit the /etc/mysql/mysql.conf.d/mysqld.cnf file and set the bind-address to 0.0.0.0. Also, uncomment the lines of server-id and log_bin properties.

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Steps on performing the full-text search on MySQL

1. Creating a full-text searchable table:

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DROP TABLE IF EXISTS ft;
CREATE TABLE ft (
    entryID INT AUTO_INCREMENT,
    entry text,
    PRIMARY KEY (entryID),
    FULLTEXT (entry));

2. Adding Rows into the table:

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   INSERT INTO ft VALUES (1, 'I was born in michigan in 1980 in a small town called Adrian. My mother is named Sue, while my father is named Mike. They currently live in a small town called East Jordan. On April 27th, 2003 I will graduate from Eastern Michigan University with a degree in Computer Information Systems.'); INSERT INTO ft VALUES (2, 'While I was at work today I was having some problems with the RAID array. It seems that we have a rogue cron script that is causing problems. When I find out more info I will post it here.'); INSERT INTO ft VALUES (3, 'After I graduate I am taking a 2 week vacation. On my agenda is a trip to Washington DC to see my girlfriend\'s sister as well as throwing a few discs at the local disc golf course.');

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I bought a Raspberry Pi for my IOT course this quarter. This little guy is so powerful. So why not have a try with something interesting.

1. Install Java

Usually Raspberry Pi should have Java Environment installed already, you can call

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$ java --version

to check. And if not, here are some simple steps for your reference.

First, update the package index

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$ sudo apt-get update

Next, install Java. You can choose either JRE or JDK.

More about JRE(Java Runtime Environment) or JDK(Java Development Kit)

leetcode

• StringBuilder has no “sb.remove()” method, try these:

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sb.deleteCharAt(sb.length() - 1);

• new boolean[] vs new Boolean[]

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boolean[] b1 = new boolean[1];
b1[0] == false;

Boolean[] b2 = new Boolean[1];
b2[0] == null;

Soommate

It’s been a while since I came out of this idea. It was when we discussed the rent distribution about each room.

In our situation, we got 4 guys would like to live in a 3b2b apartment to reduce our average rent, but no one would like to be like a host because that would be troublesome and kind of awkward since we still did not know each other well at that time. Because each room has different size and one guy should be chosen to live in the living room, its really difficult to figure out how much is each room and who wants to choose which room.

We used the most stupid way to decide: dice. Is it justice? Yeah, but I think this is not only about justice, it’s more about finding the most suitable room for each tenant. For instance, someone is rich, he does not care about how much each room takes, he just wanna live int the biggest room, the master room, with a personal bathroom in it. In other cases another guy actually does not care about what kind of room because he spent most of his time at school, then he might just choose the cheapest one. We don’t live here for several day, we are gonna live here for a while. So I believe there must be a way to figure it out.

Compare With Java

Based on the knowledge of Java, it should be easier to learn Python. I don’t wanna learn from the beginning such as: “this is a variable, and now let’s see what we can do with a variable.”
So I mark this down here, to help me learn well when comparing with Java.

to be continued…

1. Game of Life

use 2 bits to store 2 states:
[2nd bit, 1st bit] = [next state, current state]

• 00 dead (next) <- dead (current)
• 01 dead (next) <- live (current)
• 10 live (next) <- dead (current)
• 11 live (next) <- live (current) more >>