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diff --git a/Scenario/scenario_analysis_multi_site.rst b/Scenario/scenario_analysis_multi_site.rst deleted file mode 100644 index 016fe58..0000000 --- a/Scenario/scenario_analysis_multi_site.rst +++ /dev/null @@ -1,70 +0,0 @@ -5, Multisite Scenario -==================================================== - -The Multisite scenario refers to the cases when VNFs are deployed on multiple VIMs. -There could be two typical usecases for such scenario. - -One is in one DC, multiple openstack cloud are deployed. Taking consideration that the -number of compute nodes in one openstack cloud are quite limited (nearly 100) for -both opensource and commercial product of openstack, multiple openstack cloud will -have to be deployed in the DC to manage thousands of servers. VNFs in such DC should -be possible to be deployed accross openstack cloud. -..[MT] Do we anticipate HA VNFs that require more than 100 VMs so that they need to -be deployed across DCs? Or the goal is to provide higher availability by deploying -across DCs? -..[fq] Here I just try to explain what multisite scenario means. I don't think HA should -be discussed in this scenario since as you said, we can not have 100 more VMs deployed -to be HA. - -The other typical usecase is geographic redundancy. GR deployment is to deal with more -catastrophic failures (flood, earthquake, propagating software fault, and etc.) for one site. -In the Geographic redundancy usecase, VNFs are deployed in two sites, which are -geographically seperated and are managed by seperate VIM. When such a catastrophic -failure happens, the VNFs at the failed site can failover to the redundant one so as to -proceed the service. -..[MT] I agree and this scenario is definitely not limited to HA VNFs. Thus there could -be different mechanisms for the state replication between the sites and from an HA -perspective in this case it is important that the replication mechanism does not degrade -the performance at normal behaviour. - -The multisite scenario is also captured by the Multisite project, in which specific -requirements of openstack are also proposed for different usecases. However, -the multisite project mainly focuses on the requirement of these multisite -usecases on openstack. HA requirements are not necessarily the requirement -for the approaches discussed in multisite. While the HA project tries to -capture the HA requirements in these usecases. -https://gerrit.opnfv.org/gerrit/#/c/2123/ -https://gerrit.opnfv.org/gerrit/#/c/1438/. - - -An architecure of stateful VNF with redundancy in the multisite scenario can be as -follows. Architecture for the other cases can be worked out accordingly. -https://wiki.opnfv.org/_detail/stateful_vnf_in_multisite_scenario.png?id=scenario_analysis_of_high_availability_in_nfv -..[MT] What is the relation of the VMs of a single site e.g. on the left hand side? -Do they collaborate? Do they protect each other? What makes the two VIMs independent -if they need to support that VNF and its VNFM? Could they be logically the same -VIM and wouldn't that be a better solution for the VNF? -..[fq] This is kind of architecture captureed from the multisite project's work. -One VM on the left site is acting as the active VNFC, and the other VM at the right -site is acting as the standby. I assume the two VIM are cooperate with each other -under the control of the orchestrator. I am also thinking that if the two VMs contrled -by one VIM would be a better solution. But apparently that is not the scenario for -multisite, cause they are thinking multisite means you have multi openstack. - - -Below listed the additinal labor and extra requirements of multisite comparing with -the basic usecases. - -1, specific network support for the active/standby or active/active VNFs across VIM. - -In the multisite scenario, instances constructing the VNFs can be placed across VIM. -This will introduce extra network support requirement. For example, heartbeat between -active/standby VMs placed across VIM requires overlay L2 network. The IP address used -for VNF to connect with other VNFs should be able to be floating across VIM as well. - -2, in the multisite scenario, a logical instance of VNFM should be put on multiple -VIM to manage the instances of VNFs placed across the VIM. - -3, in the VM failure scenarios, recovery of failed VM requires interface between -VNFM and the VIM. In the multisite scenario, the VNFM should have knowledge of -which VIM it should communicate with so as to recover the failed VNF.
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