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[Corey Bryant <1751923@xxxxxxxxxxxxxxxxxx>]

This bug was fixed in the package nova - 2:18.3.0-0ubuntu1~cloud3
---------------

 nova (2:18.3.0-0ubuntu1~cloud3) bionic-rocky; urgency=medium
 .
   * Force refresh instance info_cache during heal (LP: #1751923):
     - d/p/0001-Force-refresh-instance-info_cache-during-heal.patch


** Changed in: cloud-archive/rocky
       Status: Fix Committed => Fix Released

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https://bugs.launchpad.net/bugs/1751923

Title:
  [SRU]_heal_instance_info_cache periodic task bases on port list from
  nova db, not from neutron server

Status in Ubuntu Cloud Archive:
  Fix Released
Status in Ubuntu Cloud Archive queens series:
  Fix Committed
Status in Ubuntu Cloud Archive rocky series:
  Fix Released
Status in Ubuntu Cloud Archive stein series:
  Fix Released
Status in OpenStack Compute (nova):
  Fix Released
Status in nova package in Ubuntu:
  Fix Released
Status in nova source package in Bionic:
  Fix Released
Status in nova source package in Disco:
  Fix Released

Bug description:
  [Impact]

  * During periodic task _heal_instance_info_cache the instance_info_caches are not updated using instance port_ids taken from neutron, but from nova db.
  * This causes that existing VMs to loose their network interfaces after reboot.

  [Test Plan]

  * This bug is reproducible on Bionic/Queens clouds.

  1) Deploy the following Juju bundle: https://paste.ubuntu.com/p/HgsqZfsDGh/
  2) Run the following script: https://paste.ubuntu.com/p/c4VDkqyR2z/
  3) If the script finishes with "Port not found" , the bug is still present.

  [Where problems could occur]

  Instances created prior to the Openstack Newton release that have more
  than one interface will not have associated information in the
  virtual_interfaces table that is required to repopulate the cache with
  interfaces in the same order they were attached prior. In the unlikely
  event that this occurs and you are using Openstack release Queen or
  Rocky, it will be necessary to either manually populate this table.
  Openstack Stein has a patch that adds support for generating this
  data. Since as things stand the guest will be unable to identify it's
  network information at all in the event the cache gets purged and
  given the hopefully low risk that a vm was created prior to Newton we
  hope the potential for this regression is very low.

  [Discussion]
  SRU team, please review the most recent version of nova	2:17.0.13-0ubuntu3 in the unapproved queue. The older version can be rejected.

  ------------------------------------------------------------------------------

  Description
  ===========

  During periodic task _heal_instance_info_cache the
  instance_info_caches are not updated using instance port_ids taken
  from neutron, but from nova db.

  Sometimes, perhaps because of some race-condition, its possible to
  lose some ports from instance_info_caches. Periodic task
  _heal_instance_info_cache should clean this up (add missing records),
  but in fact it's not working this way.

  How it looks now?
  =================

  _heal_instance_info_cache during crontask:

  https://github.com/openstack/nova/blob/ef4000a0d326deb004843ee51d18030224c5630f/nova/compute/manager.py#L6525

  is using network_api to get instance_nw_info (instance_info_caches):

            try:
                # Call to network API to get instance info.. this will
                # force an update to the instance's info_cache
                self.network_api.get_instance_nw_info(context, instance)

  self.network_api.get_instance_nw_info() is listed below:

  https://github.com/openstack/nova/blob/ef4000a0d326deb004843ee51d18030224c5630f/nova/network/neutronv2/api.py#L1377

  and it uses _build_network_info_model() without networks and port_ids
  parameters (because we're not adding any new interface to instance):

  https://github.com/openstack/nova/blob/ef4000a0d326deb004843ee51d18030224c5630f/nova/network/neutronv2/api.py#L2356

  Next: _gather_port_ids_and_networks() generates the list of instance
  networks and port_ids:

      networks, port_ids = self._gather_port_ids_and_networks(
                context, instance, networks, port_ids, client)

  https://github.com/openstack/nova/blob/ef4000a0d326deb004843ee51d18030224c5630f/nova/network/neutronv2/api.py#L2389-L2390

  https://github.com/openstack/nova/blob/ef4000a0d326deb004843ee51d18030224c5630f/nova/network/neutronv2/api.py#L1393

  As we see that _gather_port_ids_and_networks() takes the port list
  from DB:

  https://github.com/openstack/nova/blob/ef4000a0d326deb004843ee51d18030224c5630f/nova/objects/instance.py#L1173-L1176

  And thats it. When we lose a port its not possible to add it again with this periodic task.
  The only way is to clean device_id field in neutron port object and re-attach the interface using `nova interface-attach`.

  When the interface is missing and there is no port configured on
  compute host (for example after compute reboot) - interface is not
  added to instance and from neutron point of view port state is DOWN.

  When the interface is missing in cache and we reboot hard the instance
  - its not added as tapinterface in xml file = we don't have the
  network on host.

  Steps to reproduce
  ==================
  1. Spawn devstack
  2. Spawn VM inside devstack with multiple ports (for example also from 2 different networks)
  3. Update the DB row, drop one interface from interfaces_list
  4. Hard-Reboot the instance
  5. See that nova list shows instance without one address, but nova interface-list shows all addresses
  6. See that one port is missing in instance xml files
  7. In theory the _heal_instance_info_cache should fix this things, it relies on memory, not on the fresh list of instance ports taken from neutron.

  Reproduced Example
  ==================
  1. Spawn VM with 1 private network port
  nova boot --flavor m1.small --image cirros-0.3.5-x86_64-disk --nic net-name=private  test-2
  2. Attach ports to have 2 private and 2 public interfaces
  nova list:
  | a64ed18d-9868-4bf0-90d3-d710d278922d | test-2 | ACTIVE | -          | Running     | public=2001:db8::e, 172.24.4.15, 2001:db8::c, 172.24.4.16; private=fdda:5d77:e18e:0:f816:3eff:fee8:3333, 10.0.0.3, fdda:5d77:e18e:0:f816:3eff:fe53:231c, 10.0.0.5 |

  So we see 4 ports:
  stack@mjozefcz-devstack-ptg:~$ nova interface-list a64ed18d-9868-4bf0-90d3-d710d278922d
  +------------+--------------------------------------+--------------------------------------+-----------------------------------------------+-------------------+
  | Port State | Port ID                              | Net ID                               | IP addresses                                  | MAC Addr          |
  +------------+--------------------------------------+--------------------------------------+-----------------------------------------------+-------------------+
  | ACTIVE     | 6c230305-43f8-42ec-9936-61fe67551168 | 96343d33-5dd2-4289-b0cc-e6c664c2ddd9 | 10.0.0.3,fdda:5d77:e18e:0:f816:3eff:fee8:3333 | fa:16:3e:e8:33:33 |
  | ACTIVE     | 71e6c6ad-8016-450f-93f2-75e7e014084d | 9e702a96-2744-40a2-a649-33f935d83ad3 | 172.24.4.16,2001:db8::c                       | fa:16:3e:6d:dc:85 |
  | ACTIVE     | a74c9ee8-c426-48ef-890f-3988ecbe95ff | 9e702a96-2744-40a2-a649-33f935d83ad3 | 172.24.4.15,2001:db8::e                       | fa:16:3e:cf:0c:e0 |
  | ACTIVE     | b89d6863-fb4c-405c-89f9-698bd9773ad6 | 96343d33-5dd2-4289-b0cc-e6c664c2ddd9 | 10.0.0.5,fdda:5d77:e18e:0:f816:3eff:fe53:231c | fa:16:3e:53:23:1c |
  +------------+--------------------------------------+--------------------------------------+-----------------------------------------------+-------------------+
  stack@mjozefcz-devstack-ptg:~$

  We can also see 4 tap interfaces in xml file:

  stack@mjozefcz-devstack-ptg:~$ sudo virsh dumpxml instance-00000002 | grep -i tap
      <target dev='tap6c230305-43'/>
      <target dev='tapb89d6863-fb'/>
      <target dev='tapa74c9ee8-c4'/>
      <target dev='tap71e6c6ad-80'/>
  stack@mjozefcz-devstack-ptg:~$

  3. Now lets 'corrupt' the instance_info_caches for this specific VM.
  We also noticed some race-condition that cause the same problem, but
  we're unable to reproduce it in devel environment.

  Original one:

  ---
  mysql> select * from instance_info_caches where instance_uuid="a64ed18d-9868-4bf0-90d3-d710d278922d"\G;
  *************************** 1. row ***************************
   created_at: 2018-02-26 21:25:31
   updated_at: 2018-02-26 21:29:17
   deleted_at: NULL
           id: 2
  network_info: [{"profile": {}, "ovs_interfaceid": "6c230305-43f8-42ec-9936-61fe67551168", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "fdda:5d77:e18e:0:f816:3eff:fee8:3333"}], "version": 6, "meta": {"ipv6_address_mode": "slaac", "dhcp_server": "fdda:5d77:e18e:0:f816:3eff:fee7:b04"}, "dns": [], "routes": [], "cidr": "fdda:5d77:e18e::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "fdda:5d77:e18e::1"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "10.0.0.3"}], "version": 4, "meta": {"dhcp_server": "10.0.0.2"}, "dns": [], "routes": [], "cidr": "10.0.0.0/26", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "10.0.0.1"}}], "meta": {"injected": false, "tenant_id": "0314943f52014a5b9bc56b73bec475e6", "mtu": 1450}, "id": "96343d33-5dd2-4289-b0cc-e6c664c2ddd9", "label": "private"}, "devname": "tap6c230305-43", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:e8:33:33", "active": true, "type": "ovs", "id": "6c230305-43f8-42ec-9936-61fe67551168", "qbg_params": null}, {"profile": {}, "ovs_interfaceid": "b89d6863-fb4c-405c-89f9-698bd9773ad6", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "fdda:5d77:e18e:0:f816:3eff:fe53:231c"}], "version": 6, "meta": {"ipv6_address_mode": "slaac", "dhcp_server": "fdda:5d77:e18e:0:f816:3eff:fee7:b04"}, "dns": [], "routes": [], "cidr": "fdda:5d77:e18e::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "fdda:5d77:e18e::1"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "10.0.0.5"}], "version": 4, "meta": {"dhcp_server": "10.0.0.2"}, "dns": [], "routes": [], "cidr": "10.0.0.0/26", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "10.0.0.1"}}], "meta": {"injected": false, "tenant_id": "0314943f52014a5b9bc56b73bec475e6", "mtu": 1450}, "id": "96343d33-5dd2-4289-b0cc-e6c664c2ddd9", "label": "private"}, "devname": "tapb89d6863-fb", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:53:23:1c", "active": true, "type": "ovs", "id": "b89d6863-fb4c-405c-89f9-698bd9773ad6", "qbg_params": null}, {"profile": {}, "ovs_interfaceid": "a74c9ee8-c426-48ef-890f-3988ecbe95ff", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "2001:db8::e"}], "version": 6, "meta": {}, "dns": [], "routes": [], "cidr": "2001:db8::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "2001:db8::2"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "172.24.4.15"}], "version": 4, "meta": {}, "dns": [], "routes": [], "cidr": "172.24.4.0/24", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "172.24.4.1"}}], "meta": {"injected": false, "tenant_id": "9c6f74dab29f4c738e82320075fa1f57", "mtu": 1500}, "id": "9e702a96-2744-40a2-a649-33f935d83ad3", "label": "public"}, "devname": "tapa74c9ee8-c4", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:cf:0c:e0", "active": true, "type": "ovs", "id": "a74c9ee8-c426-48ef-890f-3988ecbe95ff", "qbg_params": null}, {"profile": {}, "ovs_interfaceid": "71e6c6ad-8016-450f-93f2-75e7e014084d", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "2001:db8::c"}], "version": 6, "meta": {}, "dns": [], "routes": [], "cidr": "2001:db8::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "2001:db8::2"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "172.24.4.16"}], "version": 4, "meta": {}, "dns": [], "routes": [], "cidr": "172.24.4.0/24", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "172.24.4.1"}}], "meta": {"injected": false, "tenant_id": "9c6f74dab29f4c738e82320075fa1f57", "mtu": 1500}, "id": "9e702a96-2744-40a2-a649-33f935d83ad3", "label": "public"}, "devname": "tap71e6c6ad-80", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:6d:dc:85", "active": true, "type": "ovs", "id": "71e6c6ad-8016-450f-93f2-75e7e014084d", "qbg_params": null}]
  instance_uuid: a64ed18d-9868-4bf0-90d3-d710d278922d
      deleted: 0
  1 row in set (0.00 sec)
  ----

  Modified one (I removed first port from list):
  tap6c230305-43

  ----
  mysql> select * from instance_info_caches where instance_uuid="a64ed18d-9868-4bf0-90d3-d710d278922d"\G;
  *************************** 1. row ***************************
   created_at: 2018-02-26 21:25:31
   updated_at: 2018-02-26 21:29:17
   deleted_at: NULL
           id: 2
  network_info: [{"profile": {}, "ovs_interfaceid": "b89d6863-fb4c-405c-89f9-698bd9773ad6", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "fdda:5d77:e18e:0:f816:3eff:fe53:231c"}], "version": 6, "meta": {"ipv6_address_mode": "slaac", "dhcp_server": "fdda:5d77:e18e:0:f816:3eff:fee7:b04"}, "dns": [], "routes": [], "cidr": "fdda:5d77:e18e::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "fdda:5d77:e18e::1"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "10.0.0.5"}], "version": 4, "meta": {"dhcp_server": "10.0.0.2"}, "dns": [], "routes": [], "cidr": "10.0.0.0/26", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "10.0.0.1"}}], "meta": {"injected": false, "tenant_id": "0314943f52014a5b9bc56b73bec475e6", "mtu": 1450}, "id": "96343d33-5dd2-4289-b0cc-e6c664c2ddd9", "label": "private"}, "devname": "tapb89d6863-fb", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:53:23:1c", "active": true, "type": "ovs", "id": "b89d6863-fb4c-405c-89f9-698bd9773ad6", "qbg_params": null}, {"profile": {}, "ovs_interfaceid": "a74c9ee8-c426-48ef-890f-3988ecbe95ff", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "2001:db8::e"}], "version": 6, "meta": {}, "dns": [], "routes": [], "cidr": "2001:db8::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "2001:db8::2"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "172.24.4.15"}], "version": 4, "meta": {}, "dns": [], "routes": [], "cidr": "172.24.4.0/24", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "172.24.4.1"}}], "meta": {"injected": false, "tenant_id": "9c6f74dab29f4c738e82320075fa1f57", "mtu": 1500}, "id": "9e702a96-2744-40a2-a649-33f935d83ad3", "label": "public"}, "devname": "tapa74c9ee8-c4", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:cf:0c:e0", "active": true, "type": "ovs", "id": "a74c9ee8-c426-48ef-890f-3988ecbe95ff", "qbg_params": null}, {"profile": {}, "ovs_interfaceid": "71e6c6ad-8016-450f-93f2-75e7e014084d", "preserve_on_delete": false, "network": {"bridge": "br-int", "subnets": [{"ips": [{"meta": {}, "version": 6, "type": "fixed", "floating_ips": [], "address": "2001:db8::c"}], "version": 6, "meta": {}, "dns": [], "routes": [], "cidr": "2001:db8::/64", "gateway": {"meta": {}, "version": 6, "type": "gateway", "address": "2001:db8::2"}}, {"ips": [{"meta": {}, "version": 4, "type": "fixed", "floating_ips": [], "address": "172.24.4.16"}], "version": 4, "meta": {}, "dns": [], "routes": [], "cidr": "172.24.4.0/24", "gateway": {"meta": {}, "version": 4, "type": "gateway", "address": "172.24.4.1"}}], "meta": {"injected": false, "tenant_id": "9c6f74dab29f4c738e82320075fa1f57", "mtu": 1500}, "id": "9e702a96-2744-40a2-a649-33f935d83ad3", "label": "public"}, "devname": "tap71e6c6ad-80", "vnic_type": "normal", "qbh_params": null, "meta": {}, "details": {"port_filter": true, "datapath_type": "system", "ovs_hybrid_plug": true}, "address": "fa:16:3e:6d:dc:85", "active": true, "type": "ovs", "id": "71e6c6ad-8016-450f-93f2-75e7e014084d", "qbg_params": null}]
  instance_uuid: a64ed18d-9868-4bf0-90d3-d710d278922d
      deleted: 0
  ----

  4. Now lets take a look on `nova list`:

  stack@mjozefcz-devstack-ptg:~$ nova list | grep test-2
  | a64ed18d-9868-4bf0-90d3-d710d278922d | test-2 | ACTIVE | -          | Running     | public=2001:db8::e, 172.24.4.15, 2001:db8::c, 172.24.4.16; private=fdda:5d77:e18e:0:f816:3eff:fe53:231c, 10.0.0.5 |
  stack@mjozefcz-devstack-ptg:~$

  So as you see we missed one interface (private).

  Nova interface-list shows it (because it calls neutron instead nova
  itself):

  stack@mjozefcz-devstack-ptg:~$ nova interface-list a64ed18d-9868-4bf0-90d3-d710d278922d
  +------------+--------------------------------------+--------------------------------------+-----------------------------------------------+-------------------+
  | Port State | Port ID                              | Net ID                               | IP addresses                                  | MAC Addr          |
  +------------+--------------------------------------+--------------------------------------+-----------------------------------------------+-------------------+
  | ACTIVE     | 6c230305-43f8-42ec-9936-61fe67551168 | 96343d33-5dd2-4289-b0cc-e6c664c2ddd9 | 10.0.0.3,fdda:5d77:e18e:0:f816:3eff:fee8:3333 | fa:16:3e:e8:33:33 |
  | ACTIVE     | 71e6c6ad-8016-450f-93f2-75e7e014084d | 9e702a96-2744-40a2-a649-33f935d83ad3 | 172.24.4.16,2001:db8::c                       | fa:16:3e:6d:dc:85 |
  | ACTIVE     | a74c9ee8-c426-48ef-890f-3988ecbe95ff | 9e702a96-2744-40a2-a649-33f935d83ad3 | 172.24.4.15,2001:db8::e                       | fa:16:3e:cf:0c:e0 |
  | ACTIVE     | b89d6863-fb4c-405c-89f9-698bd9773ad6 | 96343d33-5dd2-4289-b0cc-e6c664c2ddd9 | 10.0.0.5,fdda:5d77:e18e:0:f816:3eff:fe53:231c | fa:16:3e:53:23:1c |
  +------------+--------------------------------------+--------------------------------------+-----------------------------------------------+-------------------+
  stack@mjozefcz-devstack-ptg:~$

  5. During this time check the logs - yes, the
  _heal_instance_info_cache has been running for a while but without
  success - stil missing port in instance_info_caches table:

  Feb 26 22:12:03 mjozefcz-devstack-ptg nova-compute[27459]: DEBUG oslo_service.periodic_task [None req-ac707da5-3413-412c-b314-ab38db2134bc service nova] Running periodic task ComputeManager._heal_instance_info_cache {{(pid=27459) run_periodic_tasks /usr/local/lib/python2.7/dist-packages/oslo_service/periodic_task.py:215}}
  Feb 26 22:12:03 mjozefcz-devstack-ptg nova-compute[27459]: DEBUG nova.compute.manager [None req-ac707da5-3413-412c-b314-ab38db2134bc service nova] Starting heal instance info cache {{(pid=27459) _heal_instance_info_cache /opt/stack/nova/nova/compute/manager.py:6541}}
  Feb 26 22:12:04 mjozefcz-devstack-ptg nova-compute[27459]: DEBUG nova.compute.manager [None req-ac707da5-3413-412c-b314-ab38db2134bc service nova] [instance: a64ed18d-9868-4bf0-90d3-d710d278922d] Updated the network info_cache for instance {{(pid=27459) _heal_instance_info_cache /opt/stack/nova/nova/compute/manager.py:6603}}

  5. Ok, so lets pretend that customer restart the VM.
  stack@mjozefcz-devstack-ptg:~$ nova reboot a64ed18d-9868-4bf0-90d3-d710d278922d --hard
  Request to reboot server <Server: test-2> has been accepted.

  6. And now check connected interfaces - WOOPS there is no
  `tap6c230305-43` on the list ;(

  stack@mjozefcz-devstack-ptg:~$ sudo virsh dumpxml instance-00000002  | grep -i tap
      <target dev='tapb89d6863-fb'/>
      <target dev='tapa74c9ee8-c4'/>
      <target dev='tap71e6c6ad-80'/>

  Environment
  ===========
  Nova master branch, devstack

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