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Thiago Vinhas


Thoughts on DevOps, cloud architecture, coding and random geekiness



Automated Cassandra Cluster on AWS

Cassandra has grown a lot the past few years and now is one of the most used NoSQL (hate this term) database for all kinds of projects.
A while ago I worked on a quick project to create a script to automatically launch and setup Cassandra clusters on AWS, with zero human iteration. I decided to share my work in case someone needs to achieve something similar.

All you really need to do is save the script bellow and make sure you have a working python environment and install the following 2 python dependencies:

pip install boto3 argparse

If you want to understand everything that is done, which is always the recommended approach, take a look at my cassandra-cluster Github repository.
Make sure you edit the credentials and any other relevant details you want, and then run the script bellow:

#!/usr/bin/env python
#######################################################
#                                                     #
#  Cassandra cluster launcher                         #
#  Developed by Thiago Vinhas <[email protected]>     #
#                                                     #
#######################################################

import boto3
import argparse

##############################################
####           AWS Credentials            ####
##############################################

conn = {
    'aws_access_key_id': 'AKIABLAHBLAHBLAHBLAH',
    'aws_secret_access_key': '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',
    'region_name': 'us-east-1'
}

userdata = "#!/bin/bash \n aws s3 cp s3://my-script-bucket/cassandra-userdata.sh .\n bash cassandra-userdata.sh"
key = 'tvinhas'
securitygroup = 'sg-7d256706'
instanceprofile = 'arn:aws:iam::686787828286:instance-profile/cassandra'

parser = argparse.ArgumentParser(description='You are fine with the defaults...')
parser.add_argument('-a', '--ami', action="store", dest="ami", default="ami-6869aa05", help="Define the AMI to be used")
parser.add_argument('-s', '--subnet', action="store", dest="subnet", default="subnet-23dc877b", help="Define the subnet to be used")
parser.add_argument('-i', '--instancetype', action="store", dest="instancetype", default="t2.large", help="Define the instance type")

args = parser.parse_args()
ami = args.ami
subnet = args.subnet
instancetype = args.instancetype

##############################################
####           Launch Instance 1          ####
##############################################

print "Launching Instance cassandra1..."

ec2 = boto3.resource('ec2', **conn)
create_instance = ec2.create_instances(
    ImageId=ami,
    MinCount=1,
    MaxCount=1,
    KeyName=key,
    InstanceType=instancetype,
    SecurityGroupIds=[securitygroup],
    UserData=userdata,
    IamInstanceProfile={
        'Arn': instanceprofile
    },
    SubnetId=subnet
)

instanceid = create_instance[0].id
instance = create_instance[0]
instance.wait_until_running()

# Tag instance
client = boto3.client('ec2', **conn)
client.create_tags(
    Resources = [instanceid],
    Tags= [{"Key": "Name", "Value": "cassandra1"}]
)

instance.load()

print "Created new instance with id %s" % instanceid
print "IP Address: %s" % instance.public_ip_address
print "Instance Type: %s\n" % instancetype


##############################################
####           Launch Instance 2          ####
##############################################

print "Launching Instance cassandra2..."

ec2 = boto3.resource('ec2', **conn)
create_instance = ec2.create_instances(
    ImageId=ami,
    MinCount=1,
    MaxCount=1,
    KeyName=key,
    InstanceType=instancetype,
    SecurityGroupIds=[securitygroup],
    UserData=userdata,
    IamInstanceProfile={
        'Arn': instanceprofile
    },
    SubnetId=subnet
)

instanceid = create_instance[0].id
instance = create_instance[0]
instance.wait_until_running()

# Tag instance
client = boto3.client('ec2', **conn)
client.create_tags(
    Resources = [instanceid],
    Tags= [{"Key": "Name", "Value": "cassandra2"}]
)

instance.load()

print "Created new instance with id %s" % instanceid
print "IP Address: %s" % instance.public_ip_address
print "Instance Type: %s\n" % instancetype


##############################################
####           Launch Instance 3          ####
##############################################

print "Launching Instance cassandra3..."

ec2 = boto3.resource('ec2', **conn)
create_instance = ec2.create_instances(
    ImageId=ami,
    MinCount=1,
    MaxCount=1,
    KeyName=key,
    InstanceType=instancetype,
    SecurityGroupIds=[securitygroup],
    UserData=userdata,
    IamInstanceProfile={
        'Arn': instanceprofile
    },
    SubnetId=subnet
)

instanceid = create_instance[0].id
instance = create_instance[0]
instance.wait_until_running()

# Tag instance
client = boto3.client('ec2', **conn)
client.create_tags(
    Resources = [instanceid],
    Tags= [{"Key": "Name", "Value": "cassandra3"}]
)

instance.load()

print "Created new instance with id %s" % instanceid
print "IP Address: %s" % instance.public_ip_address
print "Instance Type: %s\n" % instancetype