Architectural Decisions

Goals for creating OS images

• minimal set of installed packages
• customization has to be possible
• reproducible builds

Our approach

• build an image based on the published docker images of OS vendors
• add necessary packages and services in a Dockerfile for the OS to provide:
  • sudo functionality
  • an SSH-Server
  • the FRR-Suite for BGP (the servers act as a BGP router/speaker)
  • ignition for userdata execution
  • mdadm for raid fsl configuration
  • lvm for volume group fsl provisioning
  • grub for bootloader installation
  • timesyncd for NTP time synchronization
• these services will be configured by the os-installer invoked during machine provisioning by the metal-hammer
• for out-of-tree custom images, build owners might want to provide a /etc/metal/os-installer.yaml file within the image that can provide special instructions for the os-installer