Are these Linux servers VMs that are managed by our vCenters and visible in your vRO? If yes, check the workflows under Library > vCenter > Virtual Machine management > Power Management, for example, Reboot guest OS and Reset virtual machine and wait
As for the list of server names, you have several options. You can provide it as input parameter of your workflow (so the user will be able to choose the servers when the workflow is launched). Or you can define the names in a configuration (or resource) element, that your workflow will read as a first step when launched.