DropTable

Code for ASU 512 - DDS term project.

Contribution to the repo

To contribute to the project, please follow these steps:

• Fork it and clone it to your local machine git clone git@github.com:<yourUserName>/DropTable.git
• Create a new branch with the contributor_feature name git checkout -b <contributer_feature>
• Push the changes to your own branch.
• Create a PR from github.

Setup

The project is built using Python and Docker. Please follow these steps to run your local machine:

• Download Docker.
• Install psycopg2 pip install psycopg2
• git clone git@github.com:bharat787/DropTable.git
• cd DropTable. After this you are at the root directory of this project.

Your directory tree currently should be looking like this

├── README.md
├── datasets
├── docker
│   ├── master
│   │   └── config
│   │       ├── pg_hba.conf
│   │       ├── pg_ident.conf
│   │       └── postgresql.conf
│   ├── master2
│   │   └── config
│   │       ├── pg_hba.conf
│   │       ├── pg_ident.conf
│   │       └── postgresql.conf
│   ├── slave1
│   │   └── config
│   │       ├── pg_hba.conf
│   │       ├── pg_ident.conf
│   │       └── postgresql.conf
│   └── slave2
│       └── config
│           ├── pg_hba.conf
│           ├── pg_ident.conf
│           └── postgresql.conf
├── dockermongo
│   ├── README.md
│   ├── mongomaster
│   ├── mongoslave1
│   └── mongoslave2
├── main.py
├── part3.py
├── part4.py
└── part5.py

datasets has mock data CSVs for the project. Inside the docker directory you have a master docker image config and slave1 image config. You can setup more master and slaves by making more master directories mkdir -p master<#>/config and slave directories mkdir -p slave<#>/config and copying the .conf files from the respective ./config to the new ones.

Spin up your master PostgreSQL.

Create a network on which all instances will communicate:

docker network create postgres

Spin up master, run the following in docker directory:

docker run -it --rm --name master \ 
--net postgres \
-e POSTGRES_USER=postgresadmin \
-e POSTGRES_PASSWORD=admin123 \
-e POSTGRES_DB=masterdb \
-e PGDATA="/data" \
-v $(pwd)/master/pgdata:/data \
-v $(pwd)/master/config:/config \
-v $(pwd)/master/archive:/mnt/server/archive \
-p 5001:5432 \
postgres:15.0 -c 'config_file=/config/postgresql.conf'

Few things to note here:

• The above commands are for unix/linux based machines. To run on windows replace \ with backticks(`) and $(pwd) with ${PWD}.
• We name our postgresDB as masterdb, you can name it anything you want.
• We run this instance on port 5001, instead of the usual 5432.
• In this project we are using postgres 15.0, you may choose to upgrade to latest versions.

Create backup

First we will have to create a replication user to replicate master for slave instances. Run the following commands.

docker exec -it master bash

createuser -U postgresadmin -P -c 5 --replication replicationUser

exit

Take a base backup of master and put it in data directory of slave1.

docker run -it --rm \
--net postgres \
-v $(pwd)/slave1/pgdata:/data \
--entrypoint /bin/bash postgres:15.0

Take the backup by logging into master with our replicationUser and writing the backup to /data.

pg_basebackup -h master -p 5432 -U replicationUser -D /data/ -Fp -Xs -R

Spin up the slave1 instance.

docker run -it --rm --name slave1 \ 
--net postgres \
-e POSTGRES_USER=postgresadmin \
-e POSTGRES_PASSWORD=admin123 \
-e POSTGRES_DB=postgresdb \
-e PGDATA="/data" \
-v $(pwd)/slave1/pgdata:/data \
-v $(pwd)/slave1/config:/config \
-v $(pwd)/slave1/archive:/mnt/server/archive \
-p 5002:5432 \
postgres:15.0 -c 'config_file=/config/postgresql.conf'

• Please note we start this instance on port 5002.
• To setup more slave instance, repeat the backup steps and then spin them up on different ports.

Now you will have two instances of postgres running, with master as the primary postgres instance, with slave1 as a replication server. The slave1 instance can be promoted to master in case of a failover and support read-write operations.

Repeat the above steps to create more masters and slaves.