Ansible - Radically simple configuration-management, application deployment, task-execution, and multi-node orchestration engine
ServiceM8 - ServiceM8 (Service Mate) is cloud software that allows you to manage any service business. Manage jobs, produce mobile quotes and invoices on the go. Get Control.
Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Fergus - Job management software for plumbers & electricians
Puppet Enterprise - Get started with Puppet Enterprise, or upgrade or expand.
Clik - Clik Service helps field service industries organise every aspect of their business. The most important features include scheduling engineers, creating bespoke reports, invoicing, managing customers, raising job sheets and tracking stock.