We're running a multi container Docker setup on AWS Elastic beanstalk. We're in the process of load testing, and noticed that no matter what the load was, CPU% maxed out at 50%. The instance size has 2 cores, so it should be able to use both.
- The main docker container runs Ruby on Rails, and this is what gets taxed under load testing. The other containers are rarely used.
- I've double checked our TaskDefinition for ECS. This is set to allow a max of 2 cores for any container.
- I've SSH'd into the EC2 instance and monitored the container. The ruby process maxes out at 100% (1 core). I also see docker in there, but it runs at a much smaller %.
My question is: How can we remove the CPU cap on this setup? Since it doesn't seem likely that ECS is the culprit, what is?