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[Nobuto Murata <1939869@xxxxxxxxxxxxxxxxxx>]

** This bug is no longer a duplicate of bug 1969971
   Live migrations failing due to remote host identification change

** Project changed: charm-nova-cloud-controller => null-and-void

** Changed in: null-and-void
       Status: Fix Committed => Invalid

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https://bugs.launchpad.net/bugs/1939869

Title:
  block migration of config_drive_format=iso9660 doesn't take into
  account a dedicated live-migration network

Status in OpenStack Compute (nova):
  In Progress
Status in NULL Project:
  Invalid

Bug description:
  Downstream issue: https://bugs.launchpad.net/charm-nova-
  compute/+bug/1939719

  How to reproduce:
  1. Prepare two underlying networks/subnets for Libvirt+KVM based OpenStack Nova deployment (one network as main, the other as dedicated live-migration network) 
  2. Distribute SSH public keys under authorized_keys, pre-populate known_hosts (with the live-migration network IP addresses), and make sure StrictHostKeyChecking is NOT "no"
  3. Set live_migration_scheme=ssh and live_migration_inbound_addr to the ones in the live-migration network in nova.conf
  4. Launch a VM with config-drive (iso9660 as the default)
  5. Live-migrate the VM with `openstack server migrate --live-migration --block-migration`

  Expected result:
  Live migration works

  Actual result:
  Live migration fails with an error on the *destination* host at the point of:
  https://opendev.org/openstack/nova/src/commit/370830e9445c9825d1e34e60cca01fdfe88d5d82/nova/virt/libvirt/driver.py#L10170-L10189
  with:
  Command: scp -r <source_host_fqdn>:/var/lib/nova/instances/a1cc19a2-2c34-49c7-b85a-bc4a96265fea/disk.config /var/lib/nova/instances/a1cc19a2-2c34-49c7-b85a-bc4a96265fea
  Exit code: 1
  Stdout: ''
  Stderr: 'Host key verification failed.\r\n'

  The source host FQDN is used probably the code relies on
  instance.host, and it's resolved as an IP address on the main network
  instead of the live-migration network. And the IP addresses on the
  main network are not on known_hosts so the key verification failed.

  Current workaround is either using config_drive_format=vfat or
  including IP addresses of the main network in to known_hosts. But
  wondered if copying the config drive of iso9660 can be invoked on the
  source side as pushing the data using live_migration_inbound_addr
  instead of pulling the data from the destination host.

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