diff --git a/specs/6.0/1-1-nova-compute-vsphere-cluster-mapping.rst b/specs/6.0/1-1-nova-compute-vsphere-cluster-mapping.rst new file mode 100644 index 00000000..2c39e98a --- /dev/null +++ b/specs/6.0/1-1-nova-compute-vsphere-cluster-mapping.rst @@ -0,0 +1,231 @@ +.. + This work is licensed under a Creative Commons Attribution 3.0 Unported + License. + + http://creativecommons.org/licenses/by/3.0/legalcode + +==================================================== +1-1 mapping between nova-compute and vSphere cluster +==================================================== + +https://blueprints.launchpad.net/fuel/+spec/1-1-nova-compute-vsphere-cluster-mapping + +Problem description +=================== + +Currently single nova-compute service instance utilizes all vSphere clusters +(clusters that are formed by ESXi hosts) managed by a single vCenter server +which is specified by a user. This behaviour prevents user to specify a +vSphere's cluster on which user may launch a VM instance at. Currently this +decision happens automatically and is controlled by nova-scheduler logic and +vCenter DRS logic. + +:: + + +--------------------+ +------------------+ +-------------------+ + | | | | | | + | OpenStack | | vCenter server | | vSphere cluster 1 | + | Controller | | +- - - - -+-------+ | + | | | | +-------------------+ + | | | | | + ++------------------++ | | +-------------------+ + || || | | | | | + || nova-compute |--------+ - - - -+- - - - -+-------+ vSphere cluster 2 | + || || | | | | | + || || | | +-------------------+ + ++------------------++ | | | + | | | | +-------------------+ + | | | | | | | + | | | +- - - - -+-------+ vSphere cluster N | + | | | | | | + +--------------------+ +------------------+ +-------------------+ + + +A single nova-compute service instance also acts as a single point of failure, +even if we defend it with Pacemaker. If the service fails for some reason a +whole cloud loses access to compute resources. + +Also, VMware itself recommends to avoid 1-M mapping between a nova-compute +service and vSphere clusters. + +Proposed change +=============== + +Launch multiple instances of nova-compute service and configure each service to +use a single vSphere cluster. Nova-compute services will be running on +OpenStack controller nodes like it does now. We are not proposing creation of a +separate compute node for each nova-compute, because it requires us to +configure additional pacemaker group that will backup nova-compute services on +those compute nodes. It also requires a customer to procure additional hardware +to run additional nova-compute process which might be unacceptable. + +:: + + +--------------------+ + | | + | OpenStack | + | Controller | + | | + |+------------------+| +------------------+ +-------------------+ + || || | | | | + || nova-compute-1 +--------+ - - - - - - - - -+-------+ vSphere cluster 1 | + || (login1/pass1) || | | | | + || || | | +-------------------+ + |+------------------+| | | + | | | | + |+------------------+| | vCenter server | +-------------------+ + || || | | | | + || nova-compute-2 +--------+ - - - - - - - - -+-------+ vSphere cluster 2 | + || (login2/pass2) || | | | | + || || | | +-------------------+ + |+------------------+| | | + | | | | + |+------------------+| | | +-------------------+ + || || | | | | + || nova-compute-N +--------+ - - - - - - - - -+-------+ vSphere cluster N | + || (loginN/passN) || | | | | + || || | | +-------------------+ + |+------------------+| +------------------+ + +--------------------+ + +Currently we will use same credentials for all nova-computes, but in future we +must add an opportunity for user to specify different credentials for different +vSphere clusters on web UI. Nevertheless puppet manifests must be ready for +accepting different pairs of login/password. + + +Alternatives +------------ + +We can leave things as they work right now: single nova-compute instance +utilizes multiple vSphere clusters that are specified in +*/etc/nova/nova-compute.conf*. + + +Data model impact +----------------- + +None. + + +REST API impact +--------------- + +None. + + +Upgrade impact +-------------- + +None. + + +Security impact +--------------- + +None. + + +Notifications impact +-------------------- + +None. + + +Other end user impact +--------------------- + +None. + +Performance Impact +------------------ + +Controller node will be running number of nova-compute processes equal to +number of specified vSphere clusters (simple deployment mode considered as +worst case). Maximum number of ESXi hosts that are supported by vCenter is +1000, it means that each host can form a cluster of itself, so in worst case +maximum number of nova-compute instances might raise to 1000. +(http://www.vmware.com/pdf/vsphere5/r55/vsphere-55-configuration-maximums.pdf). +So controller must be able to run additional 1000 processes. + +There is a limit on number of concurrent vSphere connections to vCenter (100 +and 180 for vSphere Web Client). Some nova-computes connections must scheduled +across timeline. + +Other deployer impact +--------------------- + +None. + + +Developer impact +---------------- + +None. + + +Implementation +============== + +Assignee(s) +----------- + +Drafter: + Igor Zinovik (izinovik) + +Primary assignee: + Andrey Danin (gcon-monolake) + Igor Zinovik (izinovik) + +Reviewer: + Andrey Danin (gcon-monolake) + Evgeniya Shumakher (eshumakher) + +QA: + Tatiana Dubyk (tdubyk) + +Work Items +---------- + +#. Modify puppet manifests that will create multiple nova-compute instances in + simple deployment mode. Create appropriate configuration file for each + nova-compute instance. + +#. Modify puppet manifests that will creates multiple pacemaker's nova-compute + resources in HA deployment mode. Create one nova-compute resource and + corresponding configuration file per one vSphere cluster. + +#. Reference architecture in our documentation must be updated and reflect + implementation of this specification. + + +Dependencies +============ + +None. + + +Testing +======= + +Manual testing using checklists according to acceptance criteria below. + +Acceptance Criteria: + +Stage I: + +- Verify that OpenStack environment that is running with vCenter that manages + multiple vSphere clusters as hypervisor option runs nova-compute services on + controllers and that each nova-compute has a single vSphere cluster in its + configuration file. + + +Documentation Impact +==================== + +The proposed change modifies Reference Architecture. All vCenter related +sections must be reviewed and updated. + +References +========== +