SaltStack Platform is a Python-based open-source configuration management software and remote execution engine. Supporting the "Infrastructure as Code" approach to deployment and cloud management, the configuration management and orchestration tool enables system administrators to automate server provisioning and management tasks. The master-slave architecture of Salt permit it to work as both a push and a pull system.
GitLab is a single application for the whole DevOps lifecylce that includes not only configuration management, but also capabilities for project management, source code management, CI/CD, and monitoring. GitLab is designed for Kubernetes and cloud native applications.