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Elevate Your PostgreSQL Skills: The Ultimate Guide to Database Administration Certification

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Introduction

PostgreSQL is a robust, open-source database management system renowned for its power and flexibility. As its popularity soars, the demand for skilled PostgreSQL Database Administrators (DBAs) is skyrocketing. Certification is the gold standard that validates your expertise, setting you apart in a competitive job market. In this blog post, we’ll dive into:

  • The Value of PostgreSQL Database Administration Certification
  • Top Certification Programs
  • Exam Preparation Strategies
  • Expert Insights for Success

Why Pursue PostgreSQL Database Administration Certification?

  • Increased Earning Potential: Certified PostgreSQL professionals command higher salaries.
  • Enhanced Credibility: Earn industry recognition and boost your professional reputation.
  • Career Advancement: Certifications open doors to leadership roles and exciting opportunities.
  • Mastery Validation: Demonstrate in-depth PostgreSQL administration skills to employers and clients.

Reputable PostgreSQL Certification Programs

Conquering the PostgreSQL Certification Exam

  • Enroll in Courses: Choose training programs tailored to your preferred certification.
  • Practice, Practice, Practice: Hands-on experience with PostgreSQL administration is essential.
  • Mock Exams: Hone your exam-taking skills and identify areas for improvement with mock tests.
  • Join Online Communities: Get support, ask questions, and learn from fellow PostgreSQL professionals.

Expert Tips for PostgreSQL Certification Success

  • Industry Experience: Real-world experience is invaluable. Work on database projects to solidify your understanding.
  • Study Groups: Form study groups with others preparing for the exam to share knowledge.
  • Know the Exam Blueprint: Understand the exam format and topics covered.
  • Manage Time Wisely: Practice effective time management during the exam.

Conclusion

PostgreSQL Database Administration Certification is a game-changer for your career. By understanding the benefits, choosing the right program, and preparing strategically, you’ll unlock your potential and achieve success in the exciting world of PostgreSQL database administration.

Monitor Database Server using Prometheus & Grafana

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Prometheus is an open-source monitoring system that collects metrics from different sources, stores them, and provides a query language and visualization capabilities to analyze and alert on them. It is designed for monitoring distributed systems and microservices architectures, and provides a time-series database to store the collected data.

Grafana is also an open-source data visualization and analytics platform. It allows users to create customizable and interactive dashboards, reports, and alerts for a wide variety of data sources, including Prometheus. Grafana provides a user-friendly interface to explore and analyze the data, and supports various visualization types, such as graphs, tables, and heatmaps. It is often used as a complement to Prometheus, as it enables users to create custom dashboards and alerts based on the collected metrics.

				
					root@ip-172-31-22-198:~/monitroing# cat docker-compose.yml
version: '3.7'
services:
  prometheus:
    image: prom/prometheus:latest
    container_name: prometheus
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
    ports:
      - '9090:9090'

  grafana:
    image: grafana/grafana:latest
    container_name: grafana
    ports:
      - '3000:3000'

  node_exporter:
    image: prom/node-exporter:latest
    container_name: node_exporter
    volumes:
      - /proc:/host/proc:ro
      - /sys:/host/sys:ro
      - /:/rootfs:ro
    command:
      - '--path.procfs=/host/proc'
      - '--path.sysfs=/host/sys'
      - '--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($$|/)'
    ports:
      - '9100:9100'



root@ip-172-31-22-198:~/monitroing# cat prometheus.yml
global:
  scrape_interval: 15s

scrape_configs:
  - job_name: 'prometheus'
    static_configs:
      - targets: ['localhost:9090']

  - job_name: 'node_exporter'
    static_configs:
      - targets: ['node_exporter:9100']

The Docker Compose file defines three containers: prometheus, grafana, and node_exporter. The Prometheus configuration file specifies the global scrape interval and the targets for two jobs: prometheus and node_exporter.

The prometheus container runs the Prometheus server, and mounts the prometheus.yml file into the container as its configuration file. The container is exposed on port 9090 and mapped to the same port on the host machine (localhost:9090).

The grafana container runs the Grafana server, and is exposed on port 3000. Grafana is a popular open-source visualization platform that is often used with Prometheus to create custom dashboards and visualizations.

The node_exporter container runs the Prometheus node_exporter service, which collects system metrics from the host machine and makes them available to Prometheus. The container is exposed on port 9100 and mapped to the same port on the host machine (node_exporter:9100).

Overall, this Docker Compose file and Prometheus configuration should set up a basic monitoring stack that collects system metrics from the host machine using node_exporter, stores them in Prometheus, and allows you to visualize them using Grafana.

To start the Docker Compose stack defined in your docker-compose.yml file, you can use the docker-compose up command in the directory where the file is located.

Here are the steps to do this:

  1. Open a terminal window and navigate to the directory where your docker-compose.yml file is located (~/monitroing in your case).

  2. Run the following command:

    docker-compose up

  • This will start all the containers defined in the docker-compose.yml file and output their logs to the terminal window.

  • Once the containers are running, you should be able to access the Prometheus server at http://localhost:9090 and the Grafana server at http://localhost:3000.

    Note that the node_exporter container is not directly accessible from the host machine, but its metrics should be available to Prometheus via its internal network.

  • To stop the containers, press Ctrl+C in the terminal window where you ran the docker-compose up command. This will stop and remove all the containers.

    If you want to stop the containers without removing them, you can use the docker-compose stop command. To start the containers again after stopping them, you can use the docker-compose start command.

How to Rebuild MongoDB Replica-Set Node Fast in Few Minutes

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Sometimes it happens that the MongoDB replica set node goes out of sync from replica set members and due to high lag, it cannot synchronise itself from the replica set members.

There are traditional ways to rebuild the node, like removing the replica set node from the cluster and adding it back, but the issue arises when your database size is in TBs, and node sync takes hours or days. Also, in some cases, it degrades the performance. You use the following steps and rebuild your replica set member in a few minutes.

Step1

Remove the node from cluster

				
					Prod:PRIMARY> rs.remove("<IP Address or hostname of the node to be removed>:27017")
Step2

login to ssh to Secondary Node and delete all the content of mongodb directory folder 

Step3

Log in to the Primary node. If you don’t know who is primary run this command rs. slave(ok)  from any node and then run rs.status(). rs. status will give you the [rimary node IP address or Hostname. Just ssh or login to primary and shut the MongoDB services

				
					--Stop MongoDB

--linux 
service mongod stop
or 
sudo systemctl stop mongodb

or 

mongod --dbpath /path/to/your/db --shutdown


-- Windows
net stop MongoDB

--MongoDB prompt
> use admin
> db.shutdownServer();

or 

mongo --eval "db.getSiblingDB('admin').shutdownServer()"

-- Mac

ps -ef| grep -i mongo
kill -9 <pid></pid>
Step 4

Zip/tar the MongoDB data folder from the Primary node and Copy or SCP to the secondary node Data folder according to mongo.conf. And start the MongoDB services of primary node

Step 5

Start the MongoDB process and if it fails check the MongoDB log. If required inrse the MongoDB service timeout to 800 (TimeoutStartSec=800) and reload the process using systemctl daemon-reload. Once MongoDB services are running fine add the node from the primary. After node addition check synchronization delay using rs. printslavereplicationinfo() and once it’s zero you are GOOD!!!.

				
					Prod:PRIMARY> rs.add("<IP Address or hostname of the node to be removed>:27017")


rs.printslavereplicationinfo()

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Essential AWS Services for Database Administrators to Learn

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Why AWS?

Cloud is becoming a vital part of Database Administration because it provides various database services & Infrastructure to run Database Ecosystems instantly. AWS (Amazon Web Services) is one of the pioneers in the Cloud according to the Gartner magic quadrant. Knowing more cloud infrastructure technologies is going to give more mileage to your Administrator career. In this article, you will find some of the AWS services which Database Administrators should know as they are basic to run Database opration.

Essential AWS Services List For Database Administrator (DBA)

Network
VPCs
Subnets
Elastic IPs
Internet Gateways
Network ACLs
Route Tables
Security Groups
Private Subnets
Public Subnets
AWS Direct Connect

Virtual Machine 
EC2
AWS Work Space

Storage
EBS
EFS
S3

Database as Services (RDS)
MySQL / MariaDB
PostgreSQL
Oracle
Micrsoft SQL Server
AWS Aurora PostgreSQL/MySQL

Database Managed Services
AWS Dynamo DB
AWS Elasticsearch 
Amazon DocumentDB

Messaging & Event Base Processing 
Apache Kafka (Amazon MSK)

 

Warehousing/ OLAP /Analytics Stagging DB
AWS Redshift

 

Monitoring 
Cloud watch
Amazon Grafana
Amazon Prometheus

 

Email Service
Amazon Simple Notification Service

Security 
IAM
Secrets Manager

Database Task Automation
AWS Batch
AWS Lambda
Cloud Formation

Command-line interface (CLI) to Manage AWS Services
AWSCLI

Migration 
Database Migration Service

Budget 
AWS Cost Explorer
AWS Budgets

Some other Services & Combination worth of Exploring

Bastion Host For DBA
MongoDB running on EC2
ELK (Elastic Search , LogStach, Kibana) running on EC2
Tunnels for Non stranded ports for Database Connections for more security
pg_pool or pg_Bouncer for PostgreSQL Databases

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Running MongoDB on Docker Compose

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In this article, we will discuss how DBA can run a MongoDB instance using docker-compose. It’s very easy and quite flexible to handle. According to my opinion docker-compose removes all the installation and configuration pain when you need a test instance immediately. In a non-production environment for proof of concepts (POC) environment, you can easily use MongoDB on docker-compose.

 

High-Level Steps for Installation & Configuration

  • Install Docker 
  • Install Docker compose
  • Take the docker-compose code with MongoDB 
  • Run the docker-compose 
  • Connect to MongoDB Database
  • Connect From MongoDB from Docker bash

Prerequisites

mkdir -p /opt/docker_com_repo

cd /opt/docker_com_repo

vi docker-compose.yml

Copy Below docker compose code for MongoDB and paste in side the docker-compose.yml

 

IMP: Remove all the comments with “< abc>” From compose code

mkdir -p  /opt/mongo/datafiles/db

mkdir  -p /opt/mongo/configfiles

Docker Compose Code

version: ‘3.3’   
services:
mongodb_container:
container_name: mongodb4.0                                                                 
image: mongo:4.0                                                                                          < Container Image>
environment:
MONGO_INITDB_DATABASE: thedbadmin                                             
MONGO_INITDB_ROOT_USERNAME: root                                                < Database Admin username>
MONGO_INITDB_ROOT_PASSWORD: oracle                                          < Database Admin Password>
ports:
– 27017:27017                                                                                                     
volumes:
– /opt/mongo/datafiles/db:/data                                                     < Persistent Volume for Data files>
– /opt/mongo/configfiles:/etc/mongod                                          < Persistent volume for MongoDB configuration file>

Ruing Docker Compose

cd /opt/docker_com_repo

docker-compose up -d

Check if the MongoDB instance started?

[root@master01 mongodb]# docker-compose ps
Name Command State Ports
———————————————————————————————–
mongodb4.0 docker-entrypoint.sh mongod Up 0.0.0.0:27017->27017/tcp,:::27017->27017/tcp

Test Database connection

[root@master01 mongodb]# telnet localhost 27017
Trying ::1…
Connected to localhost.
Escape character is ‘^]’.

if looks good than go for the next step or stop the Linux firewall 

Open MongoDB compass and connect to Database. Follow the screenshots 

Click on “Fill in connection Fields individually“

Change the hostname as per your server or machine

You can hit Create database and start using MongoDB

Connect MongoDB from the command Line 

[root@master01 mongodb]# docker exec -it mongodb4.0 bash

root@58054f03c382:/# mongo -u root -p
MongoDB shell version v4.0.24
Enter password:
connecting to: mongodb://127.0.0.1:27017/?gssapiServiceName=mongodb
Implicit session: session { “id” : UUID(“0d7bb9a1-9549-491c-89c3-dfc9caab7547”) }
MongoDB server version: 4.0.24
Server has startup warnings:
2021-10-02T09:05:13.292+0000 I CONTROL [initandlisten]
2021-10-02T09:05:13.293+0000 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/enabled is ‘always’.
2021-10-02T09:05:13.293+0000 I CONTROL [initandlisten] ** We suggest setting it to ‘never’
2021-10-02T09:05:13.293+0000 I CONTROL [initandlisten]
2021-10-02T09:05:13.293+0000 I CONTROL [initandlisten] ** WARNING: /sys/kernel/mm/transparent_hugepage/defrag is ‘always’.
2021-10-02T09:05:13.293+0000 I CONTROL [initandlisten] ** We suggest setting it to ‘never’
2021-10-02T09:05:13.293+0000 I CONTROL [initandlisten]
—
Enable MongoDB’s free cloud-based monitoring service, which will then receive and display
metrics about your deployment (disk utilization, CPU, operation statistics, etc).

The monitoring data will be available on a MongoDB website with a unique URL accessible to you
and anyone you share the URL with. MongoDB may use this information to make product
improvements and to suggest MongoDB products and deployment options to you.

To enable free monitoring, run the following command: db.enableFreeMonitoring()
To permanently disable this reminder, run the following command: db.disableFreeMonitoring()
—

> show databases;
admin 0.000GB
config 0.000GB
local 0.000GB

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