=============================================== Scripts to migrate from nova-network -> Neutron

These scripts will migrate an install a simple flat nova-network setup to Neutron. It will use linuxbridge plugin.

"simple" and "flat" meaning one or more shared provider networks (neutron speak)

It requires that the control pane will be unavailable to users during the migration. Instance traffic will largely be unaffected with a ~5 second downtime while renaming the interfaces. The nova-api-metadata service will also be unavailable during the migration

This has been tested in a Juno environment.

Steps to migrate

Prep

• Setup neutron DB and server
• Collect all you network information
• install neutron ml2 linuxdridge on compute nodes. (ensure stopped)

Gameday

• Lock down APIs - Ensure users can't access nova and neutron or anything that would in turn touch nova or neutron (eg. trove). Compute nodes and control infrastructure will still need access.
• Run the 'generate_network_data.py' script. This will collect all network data and store in a DB table. This is required as duing the migration the network information coming from the API may disapear as instance info_cache network_info changes.
• Enable Neutron endpoints in keystone
• Change compute driver on all your hypervisors to fake.FakeDriver and setup necessary configs in nova to use neutron
• Stop nova-network and nova-api-metadata everywhere
• Run 'migrate-control.py' script, this will create the networks and subnets in neutron and also create all the ports. It will then simulate interface attaches (This is where the fake driver comes in)
• Run migrate-secgroup.py script
• Start network node services neutron-*(metadata, dhcp, linuxbridge)
• install neutron ml2 linuxdridge on compute nodes. (ensure stopped)
• Run 'migrate-compute.py' script - This will rename the interfaces the way neutron expects them to be.
• Set compute driver back to libvirt and start neutron-linux-bridge
• Clear iptables and restart nova-compute and neutron-linuxbridge
• (May be needed) Add rule for metadata iptables -t nat -I PREROUTING -d 169.254.169.254/32 -p tcp -m tcp --dport 80 -j DNAT --to-destination <metadata_host>:80 - this may be needed depending on how your metadata works
• killall nova dnsmasq process

Gotchas

• You can't migrate instances in suspended state, this is because the libvirt xml imformation is stored in binary in the .save file
• IPv6 hasn't been tested yet.