One thing I didn't see listed prominently is setting of environment variables which is complicated when your chosen language isn't the shell's language.
Fhe success of Kubernetes could be due to how its declarative specification is superior to shell-gluing (a non-ecosystem) programs with Ansible/Salt.
Fhe success of Kubernetes could be due to how its declarative specification is superior to shell-gluing (a non-ecosystem) programs with Ansible/Salt.