I created multiple (say 16) AWS EC2 ubuntu instances such as:
I want to keep these instances to have the same settings for later jobs. My question is how I could manage them jointly. For example, how could I install Docker in all of them at once and so that I can use docker swarm?
Ideally you would actually configure the server build before you deploy the 16 instances.
You would launch a fresh Ubuntu server and install all of the software on it with its configuration. Once all software is installed you'd create an AMI. When you go to launch the 16 servers you'd go ahead with launching them from your AMI instead of the Ubuntu image.
To follow best practices you'd not do this installation by hand, instead using a configuration automation tool such as Ansible, Chef or Puppet to configure the server to your liking.
You can make use of aws user data to install same software on all the instance during ec2 creation. https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/user-data.html
