Admin network on bond

https://blueprints.launchpad.net/fuel/+spec/admin-network-on-bond

This blueprint describes a way to bond admin interface using non-lacp bond modes.

Problem description

In some cases user wants to bond admin interface. It is not possible for FUEL 6.0 and earlier release using UI. It is possible to bond admin interface via API and CLI, but in this case there is a problem with determining admin interface mac address during the provisioning stage. This is Nailgun provisioning serializer issue. If admin interface was bonded, serializer returns mac of the bond interface(empty value) and it breaks provisioning process.

Proposed change

Nailgun provisioning serializer should be fixed to handle case when admin interface is bonded. Serializer may return first bonded slave interface mac address instead bond mac address. Lacp modes should be denied for admin interface via Nailgun API(add validation rules).

Additional pxe db field should be added into the nic interfaces db model to properly track initial admin interface(node’s interface what was used for node’s registering in Nailgun API). It necessary for identifying pxe interface if user decide to disassemble bond which includes admin interface. This property will be sent in registration request from Nailgun agent. Nailgun agent will identify pxe interface by:

• ip address ( if some of node’s interfaces IPs belong to the same network as IP for Nailgun API which is taken from configuration file “/etc/nailgun-agent/config.yaml”)
• mac address ( Nailgun agent does already have an ability to identify interface which belongs to network with default gateway; it helps to identify admin interface during the bootstrap stage ) in case if we are using multiple node groups

This property will be automatically calculated in the Nailgun(on the data from Nailgun agent) and user will not be able to change it.

Possibility to bond admin interface via UI should be added. Available bond modes for admin interface in UI should be limited(only non-lacp modes). This limitation will be described in metadata which describes bonding settings in following way:

bonding:
    linux:
      mode:
        - values: ["balance-rr", "active-backup"]
        - values: ["802.3ad"]
          condition: "'experimental' in version:feature_groups or
                      interface:pxe == false"
        - values: ["balance-xor", "broadcast", "balance-tlb",
                   "balance-alb"]
          condition: "'experimental' in version:feature_groups"

“interface:pxe == false” condition indicates interfaces which are able to be bonded using lacp mode. This flag calculation will be based on interfaces’s property : pxe.

It is proposed to use only non-lacp bond modes for admin interface due to complex and unclear implementation in regarding to following reasons:

• During the pre-provisioning (bootstrap) and provisioning stages the switch sees both ports up and may attempt to send traffic on both, depending on load balancing algorithms. This behaviour may crush PXE booting and OS installing processes.
• It’s not clear when lacp bonding should be enabled on the node(before the OS installation, after OS installation, etc.)

But, there are several switches models what support fallback to non-bond mode if LACP session did not established. So, It was decided to allow using of lacp mode for admin interface in experimental mode. UI condition “‘experimental’ in version:feature_groups” describes it.

Alternatives

None

Data model impact

Additional pxe boolean db field should be added into the node_nic_interfaces DB model.

REST API impact

Additional API validation rules should be added to prevent passing of lacp bond mode for admin interface. Also API will be extended with rules preventing assignment of admin network to non-pxe interface.

Upgrade impact

Additional pxe field will be injected into nic interfaces db model and set to True for interfaces which belong to admin network during the database migration procedure. Also Nailgun server code will be fixed to properly calculate pxe interface in case if we have no pxe property set for any interface (to support old Nailgun agent versions). Calculation will be based on ‘node.mac’ property which is present in old agent’s versions. Admin interface’s bonding is not allowed for old releases, so metadata for old releases will be updated to not allow any bonding mode for pxe interface.

Updated metadata example:

bonding:
    linux:
      mode:
        - values: ["balance-rr", "active-backup", "802.3ad"]
          condition: "interface:pxe == false"
        - values: ["balance-xor", "broadcast", "balance-tlb",
                   "balance-alb"]
          condition: "interface:pxe == false and "
                     "'experimental' in version:feature_groups and "

Security impact

None

Notifications impact

None

Other end user impact

User will be able to bond admin interface via UI, API and CLI using non-lacp modes.

Performance Impact

None

Plugin impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Valyavskiy Viacheslav <slava-val-al>

Work Items

• Fix provisioning serializer to proper handle case when admin interface is bonded
• Deny lacp modes for admin interface via Nailgun API
• Deny to reassign admin network on non pxe interface via Nailgun API
• Add possibility to bond admin interface via UI
• Limit bond modes for admin interface via UI
• Fix Nailgun to stick pxe property to admin interface during the bootstrap stage
• Fix Nailgun agent to calculate pxe property for interfaces

Acceptance criteria

User is able to bond admin interface using non-lacp bond modes. User is able to bond admin interface using lacp bond modes in experimental mode.

Dependencies

None

Testing

It is necessary to improve devops to support tests with admin interface bonding.

Documentation Impact

Extend Deployment Guide with following items: * add new possible network topologies * how to prepare an env for installation with bonded admin interface * how to deploy OpenStack env with bonded admin interface

References

• https://blueprints.launchpad.net/fuel/+spec/admin-network-on-bond