The Proof of Work step in Blockchain is an Embarrassingly Parallelizable process, CND facilitates the search of the Golden Nonce with a local implementation and in the Cloud.
It is required to specify the difficulty with the -d or --difficulty flags.
python app/simple_finder.py --difficulty 6
By default a block is built with data "COMSM0010cloud". This can be changed with the -a or --data flags.
python app/simple_finder.py --difficulty 6 --data <text>
By default the Prepending Zeros implementation is used.
CND spins up N workers in the cloud to split the overall tasks in smaller and parallelizable ones.
- Install boto3.
- Setup AWS Athentication credentials.
It is neccessary to specify a IAM role for the virtual machines to be assigned the requires credentials to access other AWS resources. The default ARN for this is EMR_EC2_DefaultRole every AWS account comes with it by default. However, make sure you have that role setup or specify another one by setting the following environmental variable.
export CND_IAM_PROFILE=MY_EC2_Role
python cnd.py -d <difficulty> -n <num_of_workers>
In order to stop a search in progress, open a new terminal and execute:
python scram.py
If the search finished by a message found in the StopQueue all instances should be cleanly terminated. In unexpected cases such as search search interrupted by keyboard (e.g. cmd + z), instances should be terminated manually through the AWS console.