AWS Certified Database - Specialty

This is Sanjib Behera, passed the new AWS Certified Database Specialty exam on 26th Sep 2020.

This new exam focuses on all the Database services provided by AWS (RDS/Aurora/DynamoDB/ElastiCache for REDIS/ElastiCache for Memcached/Redshift/DocumentDB(Mongo)/QLDB/Neptune/Keyspaces(Cassandra)), just note that Timestream is still in beta on this time of writing, maybe sometime later it will be generally available. Also CloudFormation service for IAC and (DMS & SCT) services for migration. Additionally, CloudWatch service, S3, EBS (backups & snapshots), HA/FT/DR questions will be asked, also there will be questions where you need to choose between SSM parameter store/Secrets Manager, so knowing the difference between them is necessary, Security in Transit/Security at Rest queries will be asked. Make sure you know the difference between MultiAZ and Read Replicas and how to encrypt unencrypted DBs and the migration techniques and strategies. Also, make sure you understand Multi-master concept, Global table concept, Serverless DB concept, which is more favorable in which use-case. Whether to use ElastiCache or Read Replica can do the work.

I have working with Databases especially RDBMS databases from the last 19 years(including my college days) & NoSQL DBs from the last 3 years. So I have good know-how about them already and also working with AWS services has helped to understand how they work in and outs. But still, I did not have exposure to few AWS DB services like Aurora (which features heavily in the exam), and NoSQL DB like QLDB/Neptune/Keyspaces.

So at first, I downloaded their documentation from AWS documentation and also went through the AWS online training for free online courses. Also, I started reading the AWS Database blog to gain my knowledge. Below are a few links from AWS online training. Hope it will help everybody who will write this exam in the future.

Note: Please go through the 11th link at the very last when you are confident and are ready to appear for the exam, to do the last minute check whether you are really ready or not.

.Once I completed the AWS online training barring the last link, then I started with the Stephane Maarek & Riyaz Sayyad Udemy course for the same. Once I went through the course, I started with the Jon Bonso practice tests and was parallelly reading the AWS Database blog as well. I started my studies in the first week of September and gave the exam on 26th September.

Also, my main mantra was to study daily 6-7 hours to achieve this certification within a month. As, I am a fan of late-night studies and with a daily job, I only have that time which I use for my upskilling.

Last but not least, if you are going to give this exam, make sure you use your free AWS account to practice all the databases services and check all the features since you never know which question can be asked. Also, it is better to know which metrics are shown in CloudWatch and which in Performance Insights. Have good know-how of CloudFormation service and how it can be used to create the Databases in 1 account, multiple accounts, and in multiple regions. Also, know about the rollback strategy for DBs created via each RDS DB engine. Read the AWS Database blog site for more in-depth information. Also, I regularly follow the AWS Blog & AWS DynamoDB Twitter account to regularly update my knowledge on different usecase(s) and solutions. So these are some pointers that I use for my certifications.

So this is it, here is the detailed journey, how I went about it and what I read to crack this difficult exam.

Prerequisites

The AWS Database exam blueprint recommends that examinee’s have at least 5 years’ experience with database technologies and two years’ experience working with AWS. You should be familiar with open source SQL and NoSQL databases.

In addition, I advise you have at least AWS Associate Developer or DevOps Professional certificate before taking the exam. This would make it easier to answer questions on deployments and monitoring.

Preparation

I went through all the material prescribed in the ramp up guide. These included courses on AWS training website, user guides for all AWS purpose built databases, whitepapers and AWS Databases blog posts. I also watched re: Invent videos on DynamoDB, Elasticache, QLDB, Redshift and DocumentDB.

As part of preparations, I also used practice tests and video courses on DynamoDB and Migration from Whizlabs. I wrapped it up with the practice exam from AWS (20 questions).

General Overview

RDS and Aurora are the most tested products on the exam. These products account for 50-60% of questions on the exam. You should know the architectures of both RDS and Aurora. Features that both share and those that supported by only Aurora. DynamoDB and DocumentDB may account for about 20% of the questions. All other purpose built database products account for the remaining questions.

Before you take the exam, you should know how the following services work on AWS: VPCs, Security groups, IAM, CloudWatch, Cloudformation, CloudTrail and S3.

Even though the exam is theoretical, experience with the purpose built database services on AWS should guarantee success.

Exam Domains

1 Workload Specific Database design

This section requires you to understand all AWS database offerings and their use cases.

You should consider the following for the exam:

·         One size does not fit all. There is a database solution for every type of workload. The exam tests you on choosing the right database for the given scenario.

·         RDS (5 engines), (PostgreSQL and MySQL), Aurora, Redshift, Elasticache (Redis and Memcached), DynamoDB, DocumentDB, Keyspaces, Neptune, Timestream, QLDB are the Database offerings tested on the exam.

·         The architectures of all the database offerings.  Understand how to implement disaster recovery and high availability when using these services.

·         Understand how these services are charged, their performance (latencies) and best practices in securing data.

Pro tip:

·         RDS and Neptune use the multi-AZ architecture.

·         Aurora and DocumentDB use the shared volume architecture. Aurora supports global databases, DocumentDB does not. Compute is separated from storage and hence both are scaled differently.

·         DynamoDB supports global multi-write (hence gives low latency reads and writes). Aurora Global databases support only one writer endpoint. Aurora Multi-Master databases are regional not global.

·         Aurora Serverless databases are best suited for development and can shut down when there are no reads or writes.

·         DynamoDB, Keyspaces and QLDB are serverless.

2 Deployment and Migration

 Consider the following for the exam:

·         How to use Cloud Formation for deployments. Understand drifts, stacks, stack sets and change sets.

·         You should be familiar with the roles DMS,SCT and WQF play in migration

·         You should know when to use native migration tools, their limitations and which tool to use for which migration task

·         How to migrate LOBs

·         You should know which databases support cloning and when to use Aurora read replica to migrate a database

·         You should be know how to validate migrated data.

·         When to use snowball or Direct connect

Pro Tip:

·         Oracle handles null and time zones differently from PostgreSQL.

·         DMS is used for online migration (slow but minimizes downtime), native migration tools are used for offline migration (quick but causes downtime). You can combine both native tools and DMS (CDC) for the best of both worlds.

3 Management and Operations

This section tests your ability to perform everyday database management activities.

You should know the following for the exam:

·         Automatic/continuous backups and manual backups

·         Backup and maintenance windows

·         Considerations for minor and major engine upgrades

·         How backups, copying/sharing snapshots and read replicas meet RTO and RPO objectives

·         Parameter Groups and Option groups (permanent and persistent options)

·          How to Secrets Manager works with Databases

·         When changes are applied – rebooting instances or maintenance windows. How to applying changes immediately.

·         When to use DAX and Elasticache

·         When changes are applied – rebooting instances or maintenance windows. How to applying changes immediately.

4 Monitoring and Troubleshooting

This section tests your ability use AWS services to monitor workloads and troubleshooting common database issues.

You should know the following for the exam:

·         CloudWatch, CloudWatch Logs, RDS Events, Performance Insights, CloudTrail , Enhanced Monitoring , CloudWatch Application Insights for .Net and SQL Server and Trusted Advisor

·         Basic troubleshooting for the database offerings

·         Best practices for each database engine.

·         Read about IOPS, Tuning queries, Secondary indexes, TTL, sharding, Read Replicas etc.

5 Security

You will find questions on securing database workloads on AWS.

You should know the following for the exam:

·         KMS – which services use AWS managed keys and CMKs. Disabled/Deleted keys and their impact on workloads. Key rotation

·          

·         How IAM integrates with the various database products and how IAM DB Authentication works. Understand which services support fine-grained access control and those that do not

·         Data in Transit – How to enforce data encryption on each RDS engine. Data in transit for all other database offerings

·         VPC endpoints, VPN and Direct connect

·         Private subnets, NACLs and Security Groups

·         How to auditing works for different database products

·         Security controls supported by the different database engines

Links to Resources used

AWS Ramp-Up Guide: Databases

https://d1.awsstatic.com/training-and-certification/ramp-up-guides/RampUp_Databases_2182020.pdf

Exam Readiness: AWS Certified Database – Specialty https://www.aws.training/Details/eLearning?id=47245

AWS DynamoDB Deepdive –Beginner to Intermediate ($5)

https://www.whizlabs.com/learn/course/aws-dynamodb-deep-dive-begineer-to-intermediate/

Database Migration to AWS Masterclass ($5)

https://www.whizlabs.com/learn/course/database-migration-to-aws-master-class/

Practice Tests - 145 questions ($20)

https://www.whizlabs.com/learn/course/aws-certified-database-specialty

I did it in two weeks, you can do it too. All the best !!!

Prepare the exam by focus on exam guide. If you start from the begining (no prio DB experience, start with https://d1.awsstatic.com/training-and-certification/ramp-up-guides/RampUp_Databases_2182020.pdf Read through the recommendation.)

In the exam guide, focus on DB migration, RDS + dynamo, encryption and audit. Understand different databases use cases. Search for DB design pattern or advanced topics in reinvent videos, lvl 300-400 are usually very good.