[RFE][L3] l3-agent should have its capacity

Bug #1828494 reported by LIU Yulong on 2019-05-10
This bug affects 1 person
Affects Status Importance Assigned to Milestone
LIU Yulong

Bug Description

Recently we meet some scale issue about L3-agent. According to what I'm informed, most cloud service provider does not charge for the neutron virtual router. This can become a headach for the operators. Every tenant may create free routers for doing nothing. But neutron will create many resource for it, especially the HA scenario, there will be namespaces, keepalived processes, and monitor processes. It will absolutely increase the failure risk, especially for agent restart.

So this RFE is aimming to add a scheduling mechanism, and for l3-agent, it will collect and report some resource usage, for instance available bandiwidth. So during the router scheduler process, if there is no more available, the number of routers can be under a controlled range.

Slawek Kaplonski (slaweq) wrote :

First of all, to control number of resources used by tenants, there is quota mechanism. So it can be limited easily.
Second - is this rfe about adding new scheduler driver to https://github.com/openstack/neutron/blob/master/neutron/scheduler/l3_agent_scheduler.py ? Isn't LeastRoutersScheduler (https://github.com/openstack/neutron/blob/master/neutron/scheduler/l3_agent_scheduler.py#L344) something what You are describing here?

tags: added: rfe
LIU Yulong (dragon889) wrote :

Thanks for the feedback. I know quota. But for a public cloud, the user (tenant) may be free to register. Then they will have some free quota. The unrestricted growth of tenant number will let the router number or any other free resource reach a unbearable number of cluster.
For the second, yes, a scheduling mechanism based on some physical resource will be needed, for intance physical NIC bandwidth ratio. LeastRoutersScheduler can not work, since we do not have a maximum quantity for l3-agent. So router still is free to schedule to any l3-agent.

Changed in neutron:
assignee: nobody → LIU Yulong (dragon889)
status: New → In Progress
LIU Yulong (dragon889) wrote :
Miguel Lavalle (minsel) wrote :

Please see comments that I left in the spec

tags: added: rfe-confirmed
removed: rfe
Changed in neutron:
importance: Undecided → Wishlist
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