[knowshan]

Both Salt and Ansible look interesting. It's much easier to define system state using Ansible or Salt than Puppet.

However, I am not sure how would one use Ansible where VMs get launched dynamically (private cloud/virtualization fabric where devs can instantiate systems) and then receive their configuration without any manual steps.

For example, one can create kickstart/VM-images which get a hostname based on certain regex pattern, register with a Puppet master, the Puppet master auto-signs certs matching this specific hostname pattern and then client nodes receive their catalog. This is really useful pattern wherein systems pull their configuration state almost immediately after boot. It requires manual setup only while writing kickstart/VM-iamge profile and Puppet master configuration.

Ansible's SSH keys setup requires manual intervention, however, I think it can be automated using pre-defined keys in kickstart/VM-images. Haven't tried it yet though...

[killing_time]

Yes, having predefined keys in your VM images does the trick, and is exactly what we do for (almost) zero-intervention deployments of our servers in my particular environment.

We tend to destroy and recreate servers more often than we scale out, so we haven't bothered to remove the manual step of adding the server's hostname to the ansible inventory_hosts file. However, that's easily automatable...

Ansible will _execute_ your inventory_hosts file if it's executable, and IIRC it just needs to return a JSON or YML data structure representing all your servers and the groups they're in. So, as long as you have a library which can query your infrastructure (e.g. boto for EC2 etc) it's not hard to automate this.