openstack/manila
Code Issues Proposed changes

Update the generic driver 'Known restrictions' section

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This change addresses some limitations for considering this
driver in a production deployment of OpenStack Manila.

Closes-Bug: #1867950
Change-Id: If45d1eabb33b57440c8946a56b5af39447514792
This commit is contained in:
Vida Haririan 2023-05-25 10:15:21 -04:00
parent b3951d06dd
commit 52445fde2e
1 changed files with 18 additions and 1 deletions
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19
doc/source/admin/generic_driver.rst
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@ -146,7 +146,7 @@ Network configurations
If using ``DHSS=True``, there are two possible network configurations that can If using ``DHSS=True``, there are two possible network configurations that can
be chosen for share provisioning using this driver: be chosen for share provisioning using this driver:
- Service VM has one NIC connected to a network that connects to a public - Service VM (SVM) has one NIC connected to a network that connects to a public
router. This is, the service VM will be connected to a static administrative router. This is, the service VM will be connected to a static administrative
network created beforehand by an administrator. This approach is valid in network created beforehand by an administrator. This approach is valid in
'flat' network topologies, where a single Neutron network is defined for 'flat' network topologies, where a single Neutron network is defined for
@ -233,6 +233,23 @@ Known restrictions
``service_network_cidr`` or ``service_network_division_mask``, after manila ``service_network_cidr`` or ``service_network_division_mask``, after manila
has already created some shares using those options is not supported. has already created some shares using those options is not supported.
- One of the limitations that severely affects availability in the cloud is the
Single Point of Failure (SPOF) issue. The driver uses a Nova VM as its NAS
(NFS/CIFS) server. If/When the server goes down, there is no way to continue
serving data. Due to this SPOF, today's open source SVM solutions for
multi-tenant manila service do not really constitute a viable alternative to
using proprietary, vendor-supplied storage arrays or appliances that combine
per-tenant virtualization and solid HA recovery mechanisms. They are useful
as objects of reference and study but are not acceptable to operators of real
life clouds whose customers will not tolerate having to wait for manual
intervention to recover from unpredictable storage data path outages.
- The generic driver assumes the manila-share service is running on a node
where there is an integration bridge where it can plug in the service VM
(nova instance in this case). This condition does not hold in a common
deployment topology where manila-share is run on a controller node and
networking services are run on a separate dedicated node.
Using Windows instances Using Windows instances
~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~