Please find the latest version of these slides at:

https://code.google.com/p/ganeti/wiki/LISA2013

• Master Node
  • runs ganeti-masterd, rapi, noded, confd and mond
• Master candidates
  • have a full copy of the config, can become master
  • run ganeti-confd, noded and mond
• Master capable
  • can be upgraded to master candidates, if needed
• Regular nodes
  • cannot become master
  • get only part of the config
  • run noded and mond
• Offline nodes, are in repair

• VM capable nodes
  • can run virtual machines
• Drained nodes
  • are being evacuated
• Offlined nodes, are in repair

Core source structure:

• List of opcodes, executed in sequence
• Submitted by the cli, or via rapi, or by other jobs

• Cluster business logic
• Implemented in cmdlib

• Per-node business logic
• Implemented in backend (using bdev, hypervisor, runcmd)

• Tree of "objects" with all the cluster entities
• Replicated to all master candidates

• Flat-file export of parts of the config
• Available on all nodes

Most common customizations:

• Altering hypervisor behavior
• Adding an hypervisor parameter
• Altering cluster business logic
• Adding an option to the cluster business logic
• Adding a backend storage
• Adding a new hypervisor
• Adding a new data collector

• Edit the logic in your hypervisor's file
• For example add a command line flag to kvm, or a config value for xen

• Add the parameter in constants.py (*)
  • eg: HV_KVM_SPICE_USE_VDAGENT
• Edit the logic in your hypervisor's file
  • eg: migration bandwidth and downtime control: commit e43d4f9f

• Change the logic in cmdlib.py
• Be careful w.r.t. locking (do you need more? less?)
• Add any rpc to backend.py, rpc_defs.py, server/noded.py
• If the hypervisor interface changes, update all hypervisors

• Add the option field to opcodes.py, use the right type (see ht.py)
• Use the option in cmdlib (see "altering cluster business logic")
• Add the command line flag to cli.py and the right utility in client/*

• Implement the BlockDev interface in storage/bdev.py
• Add the logic in cmdlib (eg. migration, verify)
• Add the new storage type name to constants
• Add any parameter the new storage needs to constants
• Modify objects.Disk to suppport your storage type
  • eg: adding support for RBD: commit 7181fba

• "just" implement the hypervisor API (easy)
• Add the hypervisor name and parameters to contants.py
• Alter cmdlib as needed for supporting it
• Alter the hypervisor API as needed for supporting it

• Implement the haskell function to read the data you need
• Be careful about the availability of new dependencies
• Please submit a design if you'd like the collector to be included
• Mind latency: data collectors should be fast
• Add the collector exporting the data (eg. 2da679f)