Ansible vs Docker vs Kubernetes

Our whole DevOps stack consists of the following tools:

• @{GitHub}|tool:27| (incl. @{GitHub Pages}|tool:683|/@{Markdown}|tool:1147| for Documentation, GettingStarted and HowTo's) for collaborative review and code management tool
• Respectively @{Git}|tool:1046| as revision control system
• @{SourceTree}|tool:1599| as @{Git}|tool:1046| GUI
• @{Visual Studio Code}|tool:4202| as IDE
• @{CircleCI}|tool:190| for continuous integration (automatize development process)
• @{Prettier}|tool:7035| / @{TSLint}|tool:5561| / @{ESLint}|tool:3337| as code linter
• @{SonarQube}|tool:2638| as quality gate
• @{Docker}|tool:586| as container management (incl. @{Docker Compose}|tool:3136| for multi-container application management)
• @{VirtualBox}|tool:774| for operating system simulation tests
• @{Kubernetes}|tool:1885| as cluster management for docker containers
• @{Heroku}|tool:133| for deploying in test environments
• @{nginx}|tool:1052| as web server (preferably used as facade server in production environment)
• @{SSLMate}|tool:2752| (using @{OpenSSL}|tool:3091|) for certificate management
• @{Amazon EC2}|tool:18| (incl. @{Amazon S3}|tool:25|) for deploying in stage (production-like) and production environments
• @{PostgreSQL}|tool:1028| as preferred database system
• @{Redis}|tool:1031| as preferred in-memory database/store (great for caching)

The main reason we have chosen Kubernetes over Docker Swarm is related to the following artifacts:

• Key features: Easy and flexible installation, Clear dashboard, Great scaling operations, Monitoring is an integral part, Great load balancing concepts, Monitors the condition and ensures compensation in the event of failure.
• Applications: An application can be deployed using a combination of pods, deployments, and services (or micro-services).
• Functionality: Kubernetes as a complex installation and setup process, but it not as limited as Docker Swarm.
• Monitoring: It supports multiple versions of logging and monitoring when the services are deployed within the cluster (Elasticsearch/Kibana (ELK), Heapster/Grafana, Sysdig cloud integration).
• Scalability: All-in-one framework for distributed systems.
• Other Benefits: Kubernetes is backed by the Cloud Native Computing Foundation (CNCF), huge community among container orchestration tools, it is an open source and modular tool that works with any OS.

I am looking for an easy to use platform or VPS hosting service that will allow me to deploy additional VPS at will and quickly install the OS as well.

I am also looking for a backend software that allows team messaging (chat service, video, and audio) that can be self-hosted and is free. Also, an easy to use webRTC library would be great too!

I would recommend DigitalOcean for quick VPS creation. But it worth to consider Kubernetes or at least Docker. Once I did a project with DigitalOcean. They were guarantee kind of 90 seconds for creation of new VPS from a predefined template. But if you will decide to use Kubernetes (you can use DigitalOcean for that too, or other clouds, like Google, Azure, Amazon) - the deployment would be even much quicker than 90 seconds.