Amazon Linux 2 Setup

For what is intended to be the final production version, an Amazon EC2 instance is running Amazon Linux 2. Amazon Linux 2 includes such conveniences as pip and python pre-installed.

Setup Amazon Linux 2

Amazon Linux 2 is Amazon’s latest version of Amazon Linux. According to OS metadata, Amazon Linux 2 may be a fork of RHEL7 or the equivalent Fedora version, but built to run on the EC2 of AWS. It is a good choice for having an operating system that is fully up to date and supported by the “host.” I particularly like that it is already setup with most of what is needed. If preferred, use Ubuntu, OpenSUSE, Red Hat, et al., but your mileage will vary using this guide.

Tip

Check out the CentOS Setup Guide or the Ubuntu Setup Guide if using those distros.

Get an AWS account set up/prep for using EC2, then set up the EC2 instance itself. It is a bit of an orchestration, but worth it.

Note

  • Opted for a t3.micro instance since that’s what’s ‘in’ right now. Also used Security Groups to limit access to My IP and used a key pair.
  • It is a good idea to enable billing alerts.
  • The root volume is deleted on termination of the instance, so I enabled termination protection. Alternatively, the root volume can be changed to persist.

Configure an EBS to store the database. Went with 20 GB since that should be more than enough. Also went with magnetic storage because it costs less than SSD storage and the I/O speed is not needed.

Tip

  • Adding tags helps keep instances organized, like Name: ClashCallerBot, Category: EC2 t3.micro, Stack: Production, etc
  • When connecting from Windows operating systems, I prefer PuTTY/KiTTY, but there is a doc detailing setup.

Next, secure the EC2 instance. It is an old guide, so the only thing that needs to be done is adding a new user (with limited access, by default) to run the bot. At this point, a root volume snapshot can be made to save progress, if persistence was not enabled previously.

Tip

Setup pip and python

Install some dependencies as the default user, not the new one.

sudo yum install gcc python3-devel.x86_64 openssl-devel libffi-devel
pip3 install --upgrade pip

As the new user, set up the needed environment and select it from within the package directory:

python3 -m venv clashcallerbot-reddit/env
source clashcallerbot-reddit/env/bin/activate  # selects venv

From within the virtual environment, run:

pip install -U wheel
pip install --upgrade pip
pip install praw==6.0.0  # Still on praw6.0.0, for now
pip install mysql-connector

Setup MariaDB

Set up a MySQL database within an EBS volume as the default user. The guide is for MySQL and Ubuntu, but setup for MariaDB and Amazon Linux 2 is very similar (replace apt-get with yum, mysql with mariadb, and use sudo systemctl [start|stop] mariadb to start or stop MariaDB). Mainly follow the steps for creating and attaching an EBS volume. Fear not, the remaining steps will be summarized in this guide.

First, once the EBS volume has been created and attached, the default user needs to run the following from within the EC2 instance to create an XFS filesystem at /vol:

# Create XFS filesystem
sudo yum install xfsprogs mariadb-server mariadb-devel
grep -q xfs /proc/filesystems || sudo modprobe xfs
sudo mkfs.xfs /dev/sdf # change to wherever volume is mounted

# Mount XFS filesystem
echo "/dev/sdf /vol xfs noatime 0 0" | sudo tee -a /etc/fstab
sudo mkdir -m 000 /vol
sudo mount /vol

Now that MariaDB is installed, it must be configured.

sudo systemctl start mariadb
sudo systemctl status mariadb     # Confirm it is running
sudo mysql_secure_installation    # Say 'y' to everything!
sudo mysql -uroot -p"password"

From within the MariaDB prompt, MariaDB [(none)]>, the database can be set up.

CREATE DATABASE db_name;
USE db_name;
CREATE TABLE message_table (id INT UNSIGNED NOT NULL AUTO_INCREMENT, permalink VARCHAR(100), message VARCHAR(100),
new_date DATETIME, username VARCHAR(20), PRIMARY KEY(id));
ALTER TABLE message_table AUTO_INCREMENT=1;
GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES ON
db_name.* TO 'botname'@localhost IDENTIFIED BY 'password';
QUIT;

Tip

Alternatively, run the database.py script with the settings specified in Quickstart.

Make sure that MariaDB is stopped with sudo systemctl stop mariadb && sudo systemctl status mariadb, then move MariaDB into the EBS volume.

sudo mkdir /vol/etc /vol/lib /vol/log
sudo mv /etc/my.cnf.d /vol/etc/
sudo mv /var/lib/mysql /vol/lib/
sudo mv /var/log/mariadb /vol/log/

sudo ln -s /vol/etc/my.cnf.d /etc/my.cnf.d
sudo ln -s /vol/log/mariadb /var/log/mariadb

sudo mkdir /var/lib/mysql
echo "/vol/lib/mysql /var/lib/mysql none bind" | sudo tee -a /etc/fstab
sudo mount /var/lib/mysql

sudo systemctl start mariadb && sudo systemctl status mariadb
sudo systemctl enable mariadb  # set to start at boot

Setup ClashCallerBot

Now that python, pip, and MariaDB have been set up, the new user can download and setup the bot:

source clashcallerbot-reddit/env/bin/activate    # set virtual environment, if needed
cd clashcallerbot-reddit  # go to desired source directory
wget https://github.com/JoseALermaIII/clashcallerbot-reddit/raw/master/update.sh
chmod +x ./update.sh
./update.sh

Next, add the bot’s reddit metadata to praw-example.ini and rename to praw.ini, then add the database’s root and desired bot user credentials to database-example.ini and rename to database.ini.

Then, all requirements can be installed via pip:

pip install -r requirements.txt

Once all relevant files have been downloaded and configured, the bot can be started:

chmod +x ./clashcallerbot.sh
./clashcallerbot.sh

Tip

  • The bot has to login to reddit at least once to refresh the oauth token. Amazon Linux 2 does not have a web browser installed by default, so run sudo yum install lynx as the default user before running the script.