Enable support for iscsi multipath connections

Adds new charm config option to enable multipath
connections to iscsi volumes. This is configured
in the [libvirt] section of the nova config.

Since newton, the option has been renamed to
'volume_use_multipath'. To accomodate this,
a newton template has been created.

Change-Id: Ibbf91547c5fc41215873c63219cd83303b1d37cd
Partial-Bug: #1518001

config.yaml

@@ -406,3 +406,13 @@ options:
     description: |
       A comma-separated list of nagios servicegroups. If left empty, the
       nagios_context will be used as the servicegroup.
+  use-multipath:
+    type: boolean
+    default: False
+    description: |
+      Use a multipath connection for iSCSI volumes. Enabling this feature
+      causes libvirt to discover and login to available iscsi targets before
+      presenting the disk via device mapper (/dev/mapper/XX) to the VM instead
+      of a single path (/dev/disk/by-path/XX). If changed after deployment,
+      each VM will require a full stop/start for changes to take affect.
+

hooks/nova_compute_context.py

@@ -197,6 +197,9 @@ class NovaComputeLibvirtContext(context.OSContextGenerator):
         if config('disk-cachemodes'):
             ctxt['disk_cachemodes'] = config('disk-cachemodes')
 
+        if config('use-multipath'):
+            ctxt['use_multipath'] = config('use-multipath')
+
         if config('cpu-mode'):
             ctxt['cpu_mode'] = config('cpu-mode')
         elif ctxt['arch'] in ('ppc64el', 'ppc64le', 'aarch64'):

templates/icehouse/nova.conf

@@ -175,5 +175,8 @@ rbd_secret_uuid = {{ rbd_secret_uuid }}
 {% if disk_cachemodes -%}
 disk_cachemodes = {{ disk_cachemodes }}
 {% endif -%}
+{% if use_multipath -%}
+iscsi_use_multipath = {{ use_multipath }}
+{% endif %}
 
 {% include "parts/section-ephemeral" %}

templates/juno/nova.conf

@@ -170,6 +170,9 @@ live_migration_uri = {{ live_migration_uri }}
 {% if disk_cachemodes -%}
 disk_cachemodes = {{ disk_cachemodes }}
 {% endif %}
+{% if use_multipath -%}
+iscsi_use_multipath = {{ use_multipath }}
+{% endif %}
 
 {% include "parts/section-cinder" %}
 

templates/kilo/nova.conf

@@ -188,6 +188,9 @@ live_migration_uri = {{ live_migration_uri }}
 {% if disk_cachemodes -%}
 disk_cachemodes = {{ disk_cachemodes }}
 {% endif %}
+{% if use_multipath -%}
+iscsi_use_multipath = {{ use_multipath }}
+{% endif %}
 
 {% include "parts/section-database" %}
 

templates/liberty/nova.conf

@@ -198,6 +198,9 @@ live_migration_uri = {{ live_migration_uri }}
 {% if disk_cachemodes -%}
 disk_cachemodes = {{ disk_cachemodes }}
 {% endif %}
+{% if use_multipath -%}
+iscsi_use_multipath = {{ use_multipath }}
+{% endif %}
 
 {% include "parts/section-database" %}
 

templates/mitaka/nova.conf

@@ -208,6 +208,9 @@ disk_cachemodes = {{ disk_cachemodes }}
 # Disable tunnelled migration so that selective
 # live block migration can be supported.
 live_migration_tunnelled = False
+{% if use_multipath -%}
+iscsi_use_multipath = {{ use_multipath }}
+{% endif %}
 
 {% if virt_type == 'lxd' -%}
 [lxd]

templates/newton/nova.conf

@@ -0,0 +1,241 @@
+# mitaka
+###############################################################################
+# [ WARNING ]
+# Configuration file maintained by Juju. Local changes may be overwritten.
+{% if restart_trigger -%}
+# restart trigger: {{ restart_trigger }}
+{% endif -%}
+###############################################################################
+[DEFAULT]
+verbose={{ verbose }}
+debug={{ debug }}
+dhcpbridge_flagfile=/etc/nova/nova.conf
+dhcpbridge=/usr/bin/nova-dhcpbridge
+logdir=/var/log/nova
+state_path=/var/lib/nova
+force_dhcp_release=True
+use_syslog = {{ use_syslog }}
+ec2_private_dns_show_ip=True
+api_paste_config=/etc/nova/api-paste.ini
+enabled_apis=osapi_compute,metadata
+auth_strategy=keystone
+my_ip = {{ host_ip }}
+
+{% if arch == 'aarch64' -%}
+libvirt_use_virtio_for_bridges=False
+libvirt_disk_prefix=vd
+{% endif -%}
+
+{% if console_vnc_type -%}
+vnc_enabled = True
+novnc_enabled = True
+vnc_keymap = {{ console_keymap }}
+vncserver_listen = 0.0.0.0
+vncserver_proxyclient_address = {{ console_listen_addr }}
+{% if console_access_protocol == 'novnc' or console_access_protocol == 'vnc' -%}
+novncproxy_base_url = {{ novnc_proxy_address }}
+{% endif -%}
+{% if console_access_protocol == 'xvpvnc' or console_access_protocol == 'vnc' -%}
+xvpvncproxy_port = {{ xvpvnc_proxy_port }}
+xvpvncproxy_host = {{ xvpvnc_proxy_host }}
+xvpvncproxy_base_url = {{ xvpvnc_proxy_address }}
+{% endif -%}
+{% else -%}
+vnc_enabled = False
+novnc_enabled = False
+{% endif -%}
+
+{% if neutron_plugin and neutron_plugin in ('ovs', 'midonet') -%}
+libvirt_vif_driver = nova.virt.libvirt.vif.LibvirtGenericVIFDriver
+{% if neutron_security_groups -%}
+security_group_api = neutron
+firewall_driver = nova.virt.firewall.NoopFirewallDriver
+{% endif -%}
+{% endif -%}
+
+{% if neutron_plugin and neutron_plugin == 'vsp' -%}
+network_api_class=nova.network.neutronv2.api.API
+libvirt_vif_driver=nova.virt.libvirt.vif.LibvirtGenericVIFDriver
+neutron_ovs_bridge=alubr0
+security_group_api=neutron
+firewall_driver = nova.virt.firewall.NoopFirewallDriver
+{% endif -%}
+
+{% if neutron_plugin and (neutron_plugin == 'nvp' or neutron_plugin == 'nsx') -%}
+libvirt_vif_driver = nova.virt.libvirt.vif.LibvirtOpenVswitchVirtualPortDriver
+security_group_api = neutron
+firewall_driver = nova.virt.firewall.NoopFirewallDriver
+{% endif -%}
+
+{% if neutron_plugin and neutron_plugin == 'Calico' -%}
+security_group_api = neutron
+firewall_driver = nova.virt.firewall.NoopFirewallDriver
+{% endif -%}
+
+{% if neutron_plugin and neutron_plugin == 'plumgrid' -%}
+security_group_api=neutron
+firewall_driver = nova.virt.firewall.NoopFirewallDriver
+{% endif -%}
+
+{% if network_manager != 'neutron' and network_manager_config -%}
+{% for key, value in network_manager_config.items() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
+{% if network_manager == 'neutron' -%}
+network_api_class = nova.network.neutronv2.api.API
+use_neutron = True
+{% else -%}
+network_manager = nova.network.manager.FlatDHCPManager
+{% endif -%}
+
+{% if network_device_mtu -%}
+network_device_mtu = {{ network_device_mtu }}
+{% endif -%}
+
+{% if volume_service -%}
+volume_api_class = nova.volume.cinder.API
+{% endif -%}
+
+{% if user_config_flags -%}
+{% for key, value in user_config_flags.items() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
+{% if instances_path -%}
+instances_path = {{ instances_path }}
+{% endif -%}
+
+{% if enable_designate -%}
+notify_on_state_change = {{ notify_on_state_change }}
+{% endif -%}
+
+{% if sections and 'DEFAULT' in sections -%}
+{% for key, value in sections['DEFAULT'] -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
+{% if vcpu_pin_set -%}
+vcpu_pin_set = {{ vcpu_pin_set }}
+{% endif -%}
+reserved_host_memory_mb = {{ reserved_host_memory }}
+
+{% if pci_passthrough_whitelist -%}
+pci_passthrough_whitelist = {{ pci_passthrough_whitelist }}
+{% endif -%}
+
+{% include "section-zeromq" %}
+
+{% if default_availability_zone -%}
+default_availability_zone = {{ default_availability_zone }}
+{% endif -%}
+
+
+{% if resume_guests_state_on_host_boot -%}
+resume_guests_state_on_host_boot = {{ resume_guests_state_on_host_boot }}
+{% endif -%}
+
+{% if network_manager == 'neutron' and network_manager_config -%}
+[neutron]
+url = {{ network_manager_config.neutron_url }}
+{% if network_manager_config.keystone_host -%}
+{% if neutron_plugin and neutron_plugin == 'vsp' -%}
+ovs_bridge = alubr0
+{% endif -%}
+{% if auth_host -%}
+auth_url = {{ auth_protocol }}://{{ auth_host }}:{{ auth_port }}
+auth_type = password
+project_domain_name = default
+user_domain_name = default
+project_name = {{ admin_tenant_name }}
+username = {{ admin_user }}
+password = {{ admin_password }}
+signing_dir = {{ signing_dir }}
+{% endif -%}
+{% if metadata_shared_secret -%}
+metadata_proxy_shared_secret = {{ metadata_shared_secret }}
+service_metadata_proxy=True
+{% endif -%}
+{% endif -%}
+metadata_workers = {{ workers }}
+{% endif -%}
+
+{% include "section-keystone-authtoken-mitaka" %}
+
+{% if glance_api_servers -%}
+[glance]
+api_servers = {{ glance_api_servers }}
+{% endif -%}
+
+{% if console_access_protocol == 'spice' -%}
+[spice]
+agent_enabled = True
+enabled = True
+html5proxy_base_url = {{ spice_proxy_address }}
+keymap = {{ console_keymap }}
+server_listen = 0.0.0.0
+server_proxyclient_address = {{ console_listen_addr }}
+{% endif -%}
+
+[libvirt]
+{% if cpu_mode -%}
+cpu_mode = {{ cpu_mode }}
+{% endif -%}
+{% if cpu_model -%}
+cpu_model = {{ cpu_model }}
+{% endif -%}
+{% if libvirt_images_type -%}
+images_type = {{ libvirt_images_type }}
+{% endif -%}
+{% if libvirt_images_type and rbd_pool -%}
+images_rbd_pool = {{ rbd_pool }}
+images_rbd_ceph_conf = {{ libvirt_rbd_images_ceph_conf }}
+inject_password = false
+inject_key = false
+inject_partition = -2
+{% endif -%}
+rbd_user = {{ rbd_user }}
+rbd_secret_uuid = {{ rbd_secret_uuid }}
+{% if live_migration_uri -%}
+live_migration_uri = {{ live_migration_uri }}
+{% endif -%}
+{% if disk_cachemodes -%}
+disk_cachemodes = {{ disk_cachemodes }}
+{% endif %}
+# Disable tunnelled migration so that selective
+# live block migration can be supported.
+live_migration_tunnelled = False
+{% if use_multipath -%}
+volume_use_multipath = {{ use_multipath }}
+{% endif %}
+
+{% if virt_type == 'lxd' -%}
+[lxd]
+{% if enable_live_migration -%}
+allow_live_migration = True
+{% endif -%}
+{% if storage_pool -%}
+pool = {{ storage_pool }}
+{% endif -%}
+{% endif -%}
+
+{% include "parts/section-database" %}
+
+{% include "section-rabbitmq-oslo" %}
+
+{% include "section-oslo-notifications" %}
+
+{% include "parts/section-cinder" %}
+
+[oslo_concurrency]
+lock_path=/var/lock/nova
+
+[workarounds]
+disable_libvirt_livesnapshot = False
+
+{% include "parts/section-ephemeral" %}
+
+{% include "parts/section-serial-console" %}

templates/ocata/nova.conf

@@ -209,6 +209,9 @@ disk_cachemodes = {{ disk_cachemodes }}
 # Disable tunnelled migration so that selective
 # live block migration can be supported.
 live_migration_tunnelled = False
+{% if use_multipath -%}
+volume_use_multipath = {{ use_multipath }}
+{% endif %}
 
 {% if virt_type == 'lxd' -%}
 [lxd]

unit_tests/test_nova_compute_contexts.py

@@ -576,3 +576,22 @@ class SerialConsoleContextTests(CharmTestCase):
             {'enable_serial_console': 'true',
              'serial_console_base_url': 'ws://10.10.10.1:6083/'}
         )
+
+    def test_libvirt_use_multipath(self):
+        self.kv.return_value = FakeUnitdata(**{'host_uuid': self.host_uuid})
+        self.lsb_release.return_value = {'DISTRIB_CODENAME': 'yakkety'}
+        self.os_release.return_value = 'ocata'
+        self.test_config.set('use-multipath', True)
+        libvirt = context.NovaComputeLibvirtContext()
+
+        self.assertEqual(
+            {'libvirtd_opts': '',
+             'libvirt_user': 'libvirt',
+             'use_multipath': True,
+             'arch': platform.machine(),
+             'ksm': 'AUTO',
+             'kvm_hugepages': 0,
+             'listen_tls': 0,
+             'host_uuid': self.host_uuid,
+             'force_raw_images': True,
+             'reserved_host_memory': 512}, libvirt())