I use spot instances for my development environment; saves me a ton on GPU instance types. I have an AMI w/ NICE DCV configured, Launch Template and a ASG set up that starts one up on-demand when needed. I have EFS set up as my persistent storage. Works great honestly.

Spot instances can offer significant cost savings, but they come with the inherent risk of being interrupted when the capacity is no longer available or the Spot price exceeds your bid price. The behavior you're describing suggests a sudden and significant increase in demand for c6i instances in the us-east-1 region, leading to frequent interruptions. Reasons why they are dying may be just because there is a major increase in requests of spots such as the price is raising quicker than before, surpassing your bid. Another reason may be that they are making up for missing onDemand machines so AWS would take from the spot pool. I would suggest you review your business case on using spot instances or wait to see if it changes.

Actually there are three allocation types:

• on demand - kind of "default" mode. You request an instance, if there is free capacity, you will get the instance. No long term commitment, but once you get an instance, it's yours. It may happen that you will get a message that there is no free capacity for the specific instance type and AZ (so far it happened to me only once with AWS).

• reserved - AWS reserves the capacity for you. You have guarantee that you will get the instance type in the selected region or AZ.

• spot instance - it's kind of auction / bidding of unused capacity. You ask for an instance, you provide your maximum price and if there is free capacity and your price is at the current price or higher, you will get an instance. The difference is - if the free capacity is exhausted, or the current price is higher than your maximum bid price, your spot instance is terminated . You can get a termination warning event upfront.