Reviewed: https://review.openstack.org/400384 Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=3f8daf080411b84ec0669f0642524ce8a7d19057 Submitter: Zuul Branch: master
commit 3f8daf080411b84ec0669f0642524ce8a7d19057 Author: Lee Yarwood <lyarw...@redhat.com> Date: Mon Nov 21 15:29:30 2016 +0000 libvirt: Re-initialise volumes, encryptors, and vifs on hard reboot We call _hard_reboot during reboot, power_on, and resume_state_on_host_boot. It functions essentially by tearing as much of an instance as possible before recreating it, which additionally makes it useful to operators for attempting automated recovery of instances in an inconsistent state. The Libvirt driver would previously only call _destroy and _undefine_domain when hard rebooting an instance. This would leave vifs plugged, volumes connected, and encryptors attached on the host. It also means that when we try to restart the instance, we assume all these things are correctly configured. If they are not, the instance may fail to start at all, or may be incorrectly configured when starting. For example, consider an instance with an encrypted volume after a compute host reboot. When we attempt to start the instance, power_on will call _hard_reboot. The volume will be coincidentally re-attached as a side-effect of calling _get_guest_xml(!), but when we call _create_domain_and_network we pass reboot=True, which tells it not to reattach the encryptor, as it is assumed to be already attached. We are therefore left presenting the encrypted volume data directly to the instance without decryption. The approach in this patch is to ensure we recreate the instance as fully as possible during hard reboot. This means not passing vifs_already_plugged and reboot to _create_domain_and_network, which in turn requires that we fully destroy the instance first. This addresses the specific problem given in the example, but also a whole class of potential volume and vif related issues of inconsistent state. Because we now always tear down volumes, encryptors, and vifs, we are relying on the tear down of these things to be idempotent. This highlighted that detach of the luks and cryptsetup encryptors were not idempotent. We depend on the fixes for those os-brick drivers. Depends-On: I31d72357c89db53a147c2d986a28c9c6870efad0 Depends-On: I9f52f89b8466d03699cfd5c0e32c672c934cd6fb Closes-bug: #1724573 Change-Id: Id188d48609f3d22d14e16c7f6114291d547a8986 ** Changed in: nova Status: In Progress => Fix Released -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to OpenStack Compute (nova). https://bugs.launchpad.net/bugs/1724573 Title: encrypted volumes are directly attached to instances after a compute host reboot Status in OpenStack Compute (nova): Fix Released Bug description: Description =========== Encrypted volumes are directly attached to instances after a compute host reboot. These volumes should be decrypted by the os-brick encryptors that provide libvirt with decrypted dm devices for use by the instance/domain. This is due to the following encryptor.attach_volume call being skipped in the _hard_reboot where reboot=True as it is assumed the dm devices are already present on the host: 5204 def _create_domain_and_network(self, context, xml, instance, network_info, 5205 block_device_info=None, 5206 power_on=True, reboot=False, 5207 vifs_already_plugged=False, 5208 post_xml_callback=None, 5209 destroy_disks_on_failure=False): [..] 5218 if (not reboot and 'data' in connection_info and 5219 'volume_id' in connection_info['data']): 5220 volume_id = connection_info['data']['volume_id'] 5221 encryption = encryptors.get_encryption_metadata( 5222 context, self._volume_api, volume_id, connection_info) 5223 5224 if encryption: 5225 encryptor = self._get_volume_encryptor(connection_info, 5226 encryption) 5227 encryptor.attach_volume(context, **encryption) Steps to reproduce ================== - Create an instance with an attached encrypted volume: $ cinder type-create LUKS $ cinder encryption-type-create --cipher aes-xts-plain64 --key_size 512 --control_location front-end LUKS nova.volume.encryptors.luks.LuksEncryptor $ cinder create --display-name 'encrypted volume' --volume-type LUKS 1 $ nova boot --image cirros-0.3.5-x86_64-disk --flavor 1 test $ nova volume-attach c762ef8d-13ab-4aee-bd20-c6a002bdd172 3f2cfdf2-11d7-4ac7-883a-76217136f751 - Before continuing note that the instance is connected to the decrypted dm device: $ sudo virsh domblklist c762ef8d-13ab-4aee-bd20-c6a002bdd172 Target Source ------------------------------------------------ vda /opt/stack/data/nova/instances/c762ef8d-13ab-4aee-bd20-c6a002bdd172/disk vdb /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 $ ll /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 lrwxrwxrwx. 1 root root 56 Oct 18 08:28 /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 -> /dev/mapper/crypt-scsi-360014054c6bbc8645494397ad372e0e6 - Restart the n-cpu host _or_ fake a host reset by stopping the n-cpu service, destroying the domain, removing the decrypted dm device, unlinking the volume path before finally restarting n-cpu: $ sudo systemctl stop devstack@n-cpu $ sudo virsh destroy c762ef8d-13ab-4aee-bd20-c6a002bdd172 $ sudo cryptsetup luksClose /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 $ sudo unlink /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 $ sudo systemctl start devstack@n-cpu - The instance should be SHUTDOWN after n-cpu starts up again. So start the instance: $ nova start c762ef8d-13ab-4aee-bd20-c6a002bdd172 - The instance is restarted but now points at the original encrypted block device: $ sudo virsh domblklist c762ef8d-13ab-4aee-bd20-c6a002bdd172 Target Source ------------------------------------------------ vda /opt/stack/data/nova/instances/c762ef8d-13ab-4aee-bd20-c6a002bdd172/disk vdb /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 $ ll /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 lrwxrwxrwx. 1 root root 9 Oct 18 08:32 /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 -> ../../sde - Additional stop and start requests will not correct this: $ nova stop c762ef8d-13ab-4aee-bd20-c6a002bdd172 $ nova start c762ef8d-13ab-4aee-bd20-c6a002bdd172 $ sudo virsh domblklist c762ef8d-13ab-4aee-bd20-c6a002bdd172 Target Source ------------------------------------------------ vda /opt/stack/data/nova/instances/c762ef8d-13ab-4aee-bd20-c6a002bdd172/disk vdb /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 $ ll /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 lrwxrwxrwx. 1 root root 9 Oct 18 08:32 /dev/disk/by-id/scsi-360014054c6bbc8645494397ad372e0e6 -> ../../sde Expected result =============== The decrypted volume is attached to the instance once it is restarted. Actual result ============= The encrypted volume is attached to the instance once it is restarted. Environment =========== 1. Exact version of OpenStack you are running. See the following list for all releases: http://docs.openstack.org/releases/ # git rev-parse HEAD fce56ce8c04b20174cd89dfbc2c06f0068324b55 2. Which hypervisor did you use? (For example: Libvirt + KVM, Libvirt + XEN, Hyper-V, PowerKVM, ...) What's the version of that? Libvirt + KVM 2. Which storage type did you use? (For example: Ceph, LVM, GPFS, ...) What's the version of that? LVM+iSCSI 3. Which networking type did you use? (For example: nova-network, Neutron with OpenVSwitch, ...) N/A Logs & Configs ============== See above. 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