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Bug Reference

https://issues.apache.org/jira/browse/CLOUDSTACK-1456

Branch

Haven't branch out yet.

Introduction

Purpose

Implement isolation in advanced zone. Focus on shared network. The target is:
1. All the user VM cannot reach other user VM.
2. All the user VM can reach DHCP server and Gateway.

The mechanism we chose to implement this feature is Private VLAN.

References

Document History

Glossary

Feature Specifications

  • The isolated port(I-port) in private vlan concept fit prefect for our requirement. Basically we just need to make every user VM connect to I-port of the switch(vswitch or open vswitch), every dhcp server connect to P-port of the switch, then it would be enough for isolation and communication.
  • But open vswitch(used by XenServer and KVM) doesn't have PVLAN support. vSwitch(for VMware) support it by default.
  • So we need extra effort to simulate PVLAN on open vswitch(ovs) for Xen and KVM.
    • We would modify flow table, to:
    • 1. For every traffic leave user VM, tagged with secondary isolate vlan tag.
    • 2. Allow secondary isolated vlan tagged traffic reach DHCP server, by change the vlan tag to primary vlan tag.
    • 3. The gateway should know nothing about PVLAN, and the switch connect to the gateway should translate all the secondary vlan to primary vlan for communicating with gateway.

Assumptions / Pre-requisites

  • Need PVLAN supported switch(refer to http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a0080094830.shtml) to connect to host.
  • Only one switch would connect to gateway, other switches need to be connect to this switch via trunk port.
    • It's an ideal situation. Only Cisco Catalyst 4500 has pvlan promiscuous trunk mode to trunk both normal vlan and pvlan to pvlan-unaware switch.
    • For other Catalyst pvlan support switch, you need to connect switch to upper switch using at least (pvlan number + 1) cables to archive this.

Use cases

  • Once feature is enabled for certain shared network, all the user VMs in the network won't be able to access to each other. But the communicating with DHCP server and gateway remain the same.

Architecture and Design description

  • Straightforward for VMware to enable PVLAN feature.
  • For OVS, flow table need following modifications:
    1. For each VM:
    Outgoing tag with pvlan: priority=50,dl_src=<VM MAC> actions=mod_vlan_vid:<secondary isolated vlan>,output:<trunk port>
    2. For each VM in the same host as DHCP server:
    <a> Allow communitcation with DHCP server(e.g. DNS): priority=100,dl_src=<VM MAC>,dl_dst=<DHCP MAC> actions=NORMAL
    <b> Allow DHCP request: priority=60,udp,dl_src=<VM MAC>,nw_dst=255.255.255.255,tp_dst=67 actions=NORMAL
    3. For each host has DHCP server:
    <a> ARP for DHCP server from outside: priority=160,arp,dl_vlan=<secondary isolated vlan>, nw_dst=<DHCP IP> actions=mod_vlan_vid:<primary vlan>,NORMAL
    <b> ARP for DHCP server: priority=150,arp,nw_dst=<DHCP IP> actions=NORMAL
    <c> Accept packets from outside(e.g. DNS): priority=100,dl_vlan=<secondary isolated vlan>,dl_dst=<DHCP MAC> actions=mod_vlan_vid:<primary vlan>,NORMAL
    <d> Accept DHCP request from outside: priority=60,udp,dl_vlan=<secondary isolated vlan>,nw_dst=255.255.255.255,tp_dst=67 actions=mod_vlan_vid:<primary vlan>,NORMAL
  • The VM migration and host restart would affect the rules, need to be reprogrammed.

Switch configuration

  • Though CloudStack didn't control switch, the switches must support Private VLAN in order to get the whole setup work. This would require certain Cisco Catalyst switches.
    • It's likely we would need Catalyst 4500 series for PVLAN promiscuous trunk support.
  • The topological of switch and router would be:
    • All L2 switch(which are aware of PVLAN) connected to each other, and one of them(and only one of them) connect to router.
    • All the ports connected to the host would be configured in trunk mode, allow mgmt vlan, primary vlan(public vlan) and secondary isolated vlan.
    • The switch port connect to the router would be configured in PVLAN promiscuous trunk mode, which would translate secondary isolated vlan to primary vlan for router(which doesn't have knowledge of PVLAN).
    • If your Catalyst switch support PVLAN but not PVLAN promiscuous trunk mode(AFAIK, only Catalyst 4500 series support the mode), you need:
      • 1. Configure one of switch port as trunk for mgmt network(mgmt vlan)
      • 2. For each PVLAN, connect one port of Catalyst switch to upper switch, set the port in Catalyst Switch in promiscuous mode for one pair of PVLAN, set the port in upper switch to "access" mode, only allow traffic of primary vlan of the PVLAN pair.

Web Services APIs

PVLAN can be enabled on shared networks. Shared networks are created by admin users, end user vms are allowed to have nics on shared networks.
Modify createNetworkCmd (for shared networks)

  • Add a new parameter: secondary_isolated_vlan:
    • Not a required paramter. if the parameter is not null, then PVLAN would be enabled.
    • When the parameter is set, it must be advance shared network.

UI flow

  • The admin creates a shared vlan. She is asked if it is a PVLAN. If yes, in addition to the primary vlan id, she is asked for the secondary vlan id.
    The pre-confirmation dialog asks her to make sure her physical infrastructure is configured in the same fashion.

IP Clearance

  • what dependencies will you be adding to the project?

Appendix

Appendix A:

Appendix B:

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