My current company is small. Our servers are in AWS. You can ask AWS to pre-populate authorized_keys when launching servers. In my old company my team maintain

My current company is small. Our servers are in AWS. You can ask AWS to pre-populate authorized_keys when launching servers. In my old company my team maintained a bunch of microservices running on AWS. we used basically the same strategy, except there was one key for each service. Our application server ran on our own datacenter. Access to that was granted through LDAP, not SSH keys.