Support linux bridge on neutron helm chart¶
This specification will address enablement of LinuxBridge network virtualization for OpenStack Helm (OSH). LinuxBridge is second available networking technology in Neutron's reference architecture. The first one is OVS, that is already implemented in OSH.
The LinuxBridge (LB) is Neutron's L2 agent, using linux kernel bridges as network configuration for VMs. Both OVS and LB are part of Neutron's Modular Layer 2 (ML2) framework, allowing to simultaneously utilize the variety of layer 2 networking technologies.
Other services inside Neutron reference stack (L3/DHCP/metadata agents) are dependent on L2 connectivity agent. Thus, replacing OVS with LB would cause changes in mentioned services configuration.
LinuxBridge installation with neutron chart takes advantaged of decomposable
neutron chart in OSH. LinuxBridge agent will be added as daemonset, similarly
how OVS is implemented. New value
daemonset_lb_agent should be added in
manifests: (...) daemonset_dhcp_agent: true daemonset_l3_agent: true daemonset_lb_agent: false daemonset_metadata_agent: true daemonset_ovs_agent: true daemonset_ovs_db: true daemonset_ovs_vswitchd: true (...)
daemonset_lb_agent will be set to false to remain default
behaviour of installing OVS as networking agent.
Installing OVS requires Kubernetes worker node labeling with tag
openvswitch=enabled. To mark nodes where LB should be used, new tag
will be introduced:
LinuxBridge should support external bridge configuration, as well as auto bridge add mechanism implemented for OVS.
As mentioned before, configuration of L3/DHCP/metadata agent should be adjusted to use LinuxBridge, sample configuration override:
conf: neutron: default: agent: interface_driver: linuxbridge ml2_conf: ml2_type_flat: neutron: ml2: mechanism_drivers: linuxbridge, l2population dhcp_agent: default: neutron: base: agent: interface_driver: linuxbridge l3_agent: default: neutron: base: agent: interface_driver: linuxbridge
Having services configured, also the services pod dependencies should be updated to reflect the new kind on L2 agent:
dependencies: dhcp: pod: - requireSameNode: true labels: application: neutron component: neutron-lb-agent metadata: pod: - requireSameNode: true labels: application: neutron component: neutron-lb-agent l3: pod: - requireSameNode: true labels: application: neutron component: neutron-lb-agent
LinuxBridge should be also enabled in
manifests: daemonset_lb_agent: true daemonset_ovs_agent: false daemonset_ovs_db: false daemonset_ovs_vswitchd: false
In above example OVS and Neutron OVS agent are disabled.
Another place where Neutron L2 agent should be pointed is dependencies list
in other OpenStack projects. Currently,
nova-compute has dependency for
nova/values.yaml, it should be changed to:
dependencies: compute: daemonset: - lb-agent
No security impact.
VM networking performance would be dependent on linux bridge implementation.
OVS is an alternative in Neutron reference architecture. It is already in tree.
korzen (Artur Korzeniewski)
Add LinuxBridge daemonset
Add gate job testing VM network connectivity
Add documentation on how to use LinuxBridge
Gate job testing VM network connectivity.
Documentation on how to use LinuxBridge with Neutron chart.