Road to AWS Certification: pivot

Change of strategy in my preparation for the AWS Certified Solutions Architect Professional: I have come to the realization that the cloud guru course is not just succinct by leaving students to individual study on whitepapers and re:Invent videos, I think the execution of the course is just sloppy, not worth the money.

I would rather have a course which integrates the important bits from the Whitepapers rather than a course that says “go and read them yourself”. So I’ve looked for some opinions around and settled for the DolfinEd Udemy course, which is more expensive than the acloud.guru, but apparently more complete.

I’ve started the new course, which starts with a AWS Certified Solution Architect Associate exam simulation, to see where you are.

That took pretty much my whole slot of study for the day, the exam simulation alone took 2+ hours 😃.

What I learned from the CSAA exam simulation

I passed the exam simulation (77%, 75% was required), but I’ve realized I have some gaps I’ll need to fix before attempting the Pro Exam. In particular the gaps regarded:

• what’s the retrieval process from S3 Glacier (i.e. temporarily storing for X days on S3 Reduced Redundancy Storage)
• diffrent types of AD (AWS Directory Service > 5000 users with trust relationship with the on-premise AD, Simple AD < 5000 users, AD Connector with a gateway that redirects directory requests to your on-premise Microsoft AD without any caching)
• Redis now supports cluster mode to scale more with sharding over more primary nodes.
• Virtual Interfaces (VIF) for Direct Connect: private VIF for VPC entry points or public VIF for access to AWS services or transit VIF for AWS Transite Gateway hub
• ASG: can span multi-AZ (and auto re-balance), health check grace period after startup is 300 second by default, different auto-scaling policies

Different auto-scaling policies in particular was a topic I completely removed off my head after the certification I took 3 years ago (now I start remembering bits and pieces). There are 4 types of policies:

• Manual scaling: manually change ASC min/desired/max
• Cyclic (schedule based) scaling, for predictable load changes
• On-demand/Dynamic (event based) scaling: in response to a CW alarm (CPU utilization, memory, network I/O) or an event. You need a scale-out and scale-in policy configured. You can have a cool down timer to expire before responding to more alarms (with simple scaling) or a warm-up timer which sets the time it takes for an instance to be ready and contribute to the watched metric
• Predictive scaling (both on demand but also tries to predict future traffic based on daily and weekly trends, using Machine Learning).