I use Ansible as well and it does not allow me to scale my app containers easily, especially because of dependencies. I think I either have to manage _everything_ by Ansible including firewalls, IRB/SVI on switches, Openstack security zones, users, roles etc. or I am asking for problems and they will definitely come. NB I do not like to manage my switches, routers and firewalls with Ansible.

But my infrastructure is fairly complicated, some bare metal services, many VMs, several docker hosts with dozens of various app containers, private Openstack and some public cloud services (VPNs), Ceph cluster, nagios, ELK etc.

Ansible does not watch and maintain the infrastructure and services state - it is a passive tool (I am not sure if Tower is different). You definitely could configure your monitoring to invoke Ansible script if your app server goes down and reschedule services that ran on that host to a different one and reconfigure other parts of infrastructure as needed (dependencies, VXLANs, security rules, service discovery db update, load balancing update etc.) But you would essentially copy the Kubernetes controller functionality.

Kubernetes can take care of the service discovery, load balancing, deployment, configuration and networking and other parts of your infrastructure and it does it pretty well in my experience. It maintains the declared state and reacts to its changes.

Somebody posted here that it takes just several hours to learn it. YMMV but deploying a resilient cluster in my environment took me much more time. And I have to agree that documentation is pretty weak. E.g. provisioning Cinder volumes and connecting them to the VMs running Kubernetes nodes was a real horror.

Btw Ansible generates many of my k8s YAMLs and deploys them.