How to use spot instance with amazon elastic beanstalk?

I was asking this myself and found a builtin solution in elastic beanstalk. It was described here as follows:

• Add a file under the .ebextensions folder, for our setup we’ve named the file as spot_instance.config (the .config extension is important), paste the content available below in the file https://gist.github.com/rahulmamgain/93f2ad23c9934a5da5bc878f49c91d64
• The value for EC2_SPOT_PRICE, can be set through the elastic beanstalk environment configuration. To disable the usage of spot instances, just delete the variable from the environment settings.
• If the environment already exists and the above settings are updates, the older auto scaling group will be destroyed and a new one is created.
• The environment then submits a request for spot instances which can be seen under Spot Instances tab on the EC2 dashboard.
• Once the request is fulfilled the instance will be added to the new cluster and auto scaling group.
• You can use Spot Advisor tool to ascertain the best price for the instances in use.
• A price point of 30% of the original price seems like a decent level.

I personally would just use the on-demand price for the given instance type given this price is the upper boundary of what you would be willing to pay. This reduces the likelihood of being out-priced and thus the termination of your instances.

This might be not the best approach for production systems as it is not possible to split between a number of on-demand instances and an additional number of spot instances and there might be a small chance that there are no spot instances available as someone else is buying the whole market with high bids.

For production use cases I would look into https://github.com/AutoSpotting/AutoSpotting, which actively manages all your auto-scaling groups and tries to meet the balance between the lowest prices and a configurable number or percentage of on-demand instances.

As of 25th November 2019, AWS natively supports using Spot Instances with Beanstalk.

Spot instances can be enabled in the console by going to the desired Elastic Beanstalk environment, then selecting Configuration > Capacity and changing the Fleet composition to "Spot instance enabled".

There you can also set options such as the On-Demand vs Spot percentage and the instance types to use.

More information can be found in the Beanstalk Auto Scaling Group support page

Here at Spotinst, we were dealing with exactly that dilemma for our customers.

As Elastic Beanstalk creates a whole stack of services (Load Balancers, ASG’s, Route 53 access point etc..) that are tied together, it isn’t a simple task to manage Spots within it.

After a lot of research, we figured that removing the ASG will always be prone to errors as keeping the configuration intact gets complex. Instead, we simply replicate the ASG and let our Elastigroup and the ASG live side by side with all the scaling policies only affecting the Elastigroup and the ASG configuration updates feeding there as well.

With the instances running inside Elastigroup, you achieve managed Spot instances with full SLA.

Some of the benefits of running your Spot instances in Elastigroup include:

1) Our algorithm makes live choices for the best Spot markets in terms of price and availability whenever new instances spin up.

2) When an interruption happens, we predict it about 15 minutes in advance and take all the necessary steps to ensure (and insure) the capacity of your group.

3) In the extreme case that none of the markets have Spot availability, we simply fall back to an on-demand instance.