Generic approach for share provisioning
The Shared File Systems service can be configured to use Nova
VMs and Cinder volumes. There are two modules that handle them in manila:
1) ‘service_instance’ module creates VMs in Nova with predefined image called
service image. This module can be used by any backend driver for provisioning
of service VMs to be able to separate share resources among tenants.
2) ‘generic’ module operates with Cinder volumes and VMs created by
‘service_instance’ module, then creates shared filesystems based on volumes
attached to VMs.
Network configurations
Each backend driver can handle networking in its own way,
see: https://wiki.openstack.org/wiki/Manila/Networking
- One of two possible configurations can be chosen for share provisioning
- using ‘service_instance’ module:
- Service VM has one net interface from net that is connected to public router.
For successful creation of share, user network should be connected to public
router too.
- Service VM has two net interfaces, first one connected to service network,
second one connected directly to user’s network.
Requirements for service image
Linux based distro
NFS server
Samba server >=3.2.0, that can be configured by data stored in registry
SSH server
Two net interfaces configured to DHCP (see network approaches)
‘exportfs’ and ‘net conf’ libraries used for share actions
- Following files will be used, so if their paths differ one needs to create at
least symlinks for them:
- /etc/exports (permanent file with NFS exports)
- /var/lib/nfs/etab (temporary file with NFS exports used by ‘exportfs’)
- /etc/fstab (permanent file with mounted filesystems)
- /etc/mtab (temporary file with mounted filesystems used by ‘mount’)
Supported shared filesystems
- NFS (access by IP)
- CIFS (access by IP)
Known restrictions
- One of Nova’s configurations only allows 26 shares per server. This limit
comes from the maximum number of virtual PCI interfaces that are used for
block device attaching. There are 28 virtual PCI interfaces, in this
configuration, two of them are used for server needs and other 26 are used
for attaching block devices that are used for shares.
- Juno version works only with Neutron. Each share should be created with
neutron-net and neutron-subnet IDs provided via share-network entity.
- Juno version handles security group, flavor, image, keypair for Nova VM and
also creates service networks, but does not use availability zones for
Nova VMs and volume types for Cinder block devices.
- Juno version does not use security services data provided with share-network.
These data will be just ignored.
- Liberty version adds a share extend capability. Share access will be briefly
interrupted during an extend operation.
- Liberty version adds a share shrink capability, but this capability is not
effective because generic driver shrinks only filesystem size and doesn’t
shrink the size of Cinder volume.
The manila.share.drivers.generic Module
Generic Driver for shares.
-
class GenericShareDriver(*args, **kwargs)
Bases: manila.share.driver.ExecuteMixin, manila.share.driver.ShareDriver
Executes commands relating to Shares.
-
check_for_setup_error()
Returns an error if prerequisites aren’t met.
-
create_cgsnapshot(context, *args, **kwargs)
-
create_consistency_group(context, *args, **kwargs)
-
create_consistency_group_from_cgsnapshot(context, *args, **kwargs)
-
create_share(context, *args, **kwargs)
-
create_share_from_snapshot(context, *args, **kwargs)
-
create_snapshot(context, snapshot, share_server=None)
Creates a snapshot.
-
delete_cgsnapshot(context, *args, **kwargs)
-
delete_consistency_group(context, cg_dict, share_server=None)
Deletes a consistency group.
Since we are faking the CG object we do nothing here.
-
delete_share(context, share, share_server=None)
Deletes share.
-
delete_snapshot(context, snapshot, share_server=None)
Deletes a snapshot.
-
do_setup(context)
Any initialization the generic driver does while starting.
-
ensure_share(context, *args, **kwargs)
-
extend_share(context, *args, **kwargs)
-
get_network_allocations_number()
Get number of network interfaces to be created.
-
manage_existing(share, driver_options)
Manage existing share to manila.
Generic driver accepts only one driver_option ‘volume_id’.
If an administrator provides this option, then appropriate Cinder
volume will be managed by Manila as well.
| Parameters: |
- share – share data
- driver_options – Empty dict or dict with ‘volume_id’ option.
|
|---|
| Returns: | dict with share size, example: {‘size’: 1}
|
|---|
-
manage_existing_snapshot(snapshot, driver_options)
Manage existing share snapshot with manila.
| Parameters: |
- snapshot – Snapshot data
- driver_options – Not used by the Generic driver currently
|
|---|
| Returns: | dict with share snapshot size, example: {‘size’: 1}
|
|---|
-
shrink_share(context, *args, **kwargs)
-
unmanage_snapshot(snapshot)
Unmanage share snapshot with manila.
-
update_access(context, *args, **kwargs)
-
ensure_server(f)
The manila.share.drivers.service_instance Module
Module for managing nova instances for share drivers.
-
class BaseNetworkhelper(service_instance_manager)
Bases: object
-
NAME
Returns code name of network helper.
-
get_network_name(network_info)
Returns name of network for service instance.
-
setup_connectivity_with_service_instances()
Sets up connectivity between Manila host and service instances.
-
setup_network(network_info)
Sets up network for service instance.
-
teardown_network(server_details)
Teardowns network resources provided for service instance.
-
class NeutronNetworkHelper(service_instance_manager)
Bases: manila.share.drivers.service_instance.BaseNetworkhelper
-
NAME
-
admin_project_id
-
get_network_name(network_info)
Returns name of network for service instance.
-
neutron_api
-
service_network_id
-
setup_connectivity_with_service_instances()
Sets up connectivity with service instances.
Creates host port in service network and/or admin network, creating
and setting up required network devices.
-
setup_network(*args, **kwargs)
-
teardown_network(*args, **kwargs)
-
class NovaNetworkHelper(service_instance_manager)
Bases: manila.share.drivers.service_instance.BaseNetworkhelper
Nova network helper for Manila service instances.
All security-group rules are applied to all interfaces of Nova VM
using Nova-network. In that case there is no need to create additional
service network. Only one thing should be satisfied - Manila host
should have access to all tenant networks.
This network helper does not create resources.
-
NAME
-
get_network_name(network_info)
Returns name of network for service instance.
-
setup_connectivity_with_service_instances()
Nothing to do. Placeholder.
-
setup_network(network_info)
-
teardown_network(server_details)
Nothing to do. Placeholder.
-
class ServiceInstanceManager(driver_config=None)
Bases: object
Manages nova instances for various share drivers.
This class provides following external methods:
- set_up_service_instance: creates instance and sets up share
infrastructure.
- ensure_service_instance: ensure service instance is available.
- delete_service_instance: removes service instance and network
infrastructure.
-
delete_service_instance(context, server_details)
Removes share infrastructure.
Deletes service vm and subnet, associated to share network.
-
ensure_service_instance(context, server)
Ensures that server exists and active.
-
get_common_server()
-
get_config_option(key)
Returns value of config option.
| Parameters: | key – key of config’ option. |
|---|
| Returns: | str – value of config’s option.
first priority is driver’s config,
second priority is global config. |
|---|
-
network_helper
-
reboot_server(server, soft_reboot=False)
-
set_up_service_instance(context, network_info)
Finds or creates and sets up service vm.
| Parameters: |
- context – defines context, that should be used
- network_info – network info for getting allocations
|
|---|
| Returns: | dict with service instance details
|
|---|
| Raises: | exception.ServiceInstanceException
|
|---|
-
wait_for_instance_to_be_active(instance_id, timeout)