We are running 6 Java Spring Boot based microservice projects in one AWS t2.large(2 CPU & 8GB RAM) EC2 machine. When we see the CPU and RAM utilization of this EC2 machine, CPU is underutilized, hardly hits 1% but the RAM usage is always above 85%.
Now we want to add 2 more microservice. We definitely can't deploy these 2 services in the EC2 which we already have as the RAM will be exhausted. So, we need to add one more EC2 machine or we need to upgrade t2.large to t2.xlarge(4 CPU & 16GB RAM) to deploy the 2 new services but we also want to be cost-effective.
We are studying some of the AWS articles and it says that running ECS services will be cost-effective as the billing is based on how much CPU and RAM is being used(reference - ECS Fargate Pricing). As our CPU is always underutilized, we are thinking that ECS Fargate pricing policy will reduce our cost.
So, 3 questions with respect to cost saving for the above case,
If we prefer ECS, will that be really cost-effective than adding one more EC2 instance as ECS pricing is based on how much resources are utilized?
This is worded a little awkward, but I think what you're asking is will Fargate be more cost effective than standard EC2 instances. That, I think, is pretty difficult for us to determine for you, though you should be able to do some quick estimations based on your real-world usage and compare that with the cost of the smallest necessary instance type.
To throw another option in the mix, consider Reserved Instances, as they come at a pretty steep discount if you're willing to reserve them for some period of time. From the linked doc, you'd be looking at somewhere around a 40% discount (compared to on-demand) for a 1 year reservation, and 60% for a 3 year reservation.
Additionally, consider different instance types, specifically the memory optimized instances r4 and x1. These let you purchase more memory and less cpu.
If we need to deploy 8 projects in ECS, will that create 8 EC2 instances or we can still use 1 or 2 EC2 machines for all 8 projects deployment
Assuming you're not referring to Fargate here, the answer is ... it depends; it depends on how you design your system. You can host as many containers on an instance as you want (assuming you have the resources) -- but whether or not that's what you want from a high-availability / disaster scenario is for you to decide.
Should we completely re-think about our deployment process in a different way?
This will be answered when you come to a conclusion on your first question.