LBaaS API and Object Model improvement

https://blueprints.launchpad.net/neutron/+spec/lbaas-api-and-objmodel-improvement

LBaaS needs improved API and object model to provide base line for new API parts that provide advanced use cases such as L7, TLS, HA, etc.

This blueprint describes the changes that should be made to object model so that further design and implementation of L7 switching, TLS and HA feature is possible. The new API that exposes the new entities will be done in an separate extension.

This blueprint is not describing design of L7, TLS API parts but may briefly assume some aspects of possible design of those features. Nor does it describe the changes to the API that will fit with this object model.

Problem Description

The “advanced” LB configuration which is supported by all LB vendors, both hw and sw, may consist of multiple service endpoints on one ip address, and multiple pools. Here, ‘service endpoint’ means IP address + port.

The problem with existing API/object model is that it only accounts for single VIP and single pool per loadbalancer.

One of the biggest issue of the existing API and object model is that Pool is playing ‘root object’ role and this solely prevents multiple pools per single configuration.

Proposed Change

There are a few things that needs to be done in order to make LBaaS API suitable for addition of TLS, L7 and HA features.

1. This will entirely be a new extension and service plugin. LBaaS V1 code should not be affected, but there may be exceptions.

2. Currently Pool object is the root object(*), which is logically incorrect and confusing. From API perspective that means that creating Pool object will not be a starting point of the workflow.

  1. Member object will add subnet_id as an optional attribute.

4. VIP object will not be used. Its attributes will be added to the LoadBalancer object and the Listener object.

5. LoadBalancer object becomes the root object(*) of the LBaaS object model. It will hold the attributes that pertain to the vip and will be the parent of one or many listeners.

6. Additional object Listener is introduced, which is a placeholder for former VIP parameters such as protocol_port, and protocol, see detailed description below

LoadBalancer and Listener relate as 1:M. Listener will initially only be a child of a LoadBalancer, so its life-cycle is limited to a LoadBalancer. Deleting a LoadBalancer will not be alllowed when it has children Listeners.

In the future, this relationship may become M:N if it is decided it is needed. The M:N change will be an additive change so it will not break contract, however, this blueprint will not attempt this.

7. To prevent entities in the database being out of sync with the backend due to concurrent requests, no operations will be allowed if an entity is in a transient state (PENDING_CREATE, PENDING_UPDATE, PENDING_DELETE).

  1. Pool to Health Monitor relationship will change from M:N to 1:1 for now.

9. Attributes of health monitor and member will stay nearly identical except for references to parents.

10. A new synchronous haproxy driver will be created to easily test out the API and DB changes. It will not be meant for production use. Refactoring the agent haproxy driver will be left to another blueprint.

11. Since there are two types of statuses we should worry about, LoadBalancer and Listener will have both provisioning_status and operating_status fields, while Pool and Member will have an operating_status field.

12. operating_status will be an enum of (‘ONLINE’, ‘OFFLINE’, ‘DEGRADED’, ‘ERROR’)

13. provisioning_status will be an enum of (‘ACTIVE’, ‘PENDING_CREATE’, ‘PENDING_UPDATE’, ‘PENDING_DELETE’, ‘ERROR’)

14. Every update of a LoadBalancer, including updates to and adding/removing children entities, will put the LoadBalancer into a PENDING_UPDATE provisioning_status. No other updates to that LoadBalancer or its children will be allowed until the operation has completed.

(*) Root object is an object that represents ‘service instance’. It could be deployed/undeployed, turned on/off, or capability requirements may be applied to it. It also is a starting point of configuration workflow.

Alternatives

Data Model Impact

LBaaS v1 tables will remain unchanged and the following tables will be added for LBaaS v2 use: * neutron.lbaas_loadbalancers * neutron.lbaas_listeners * neutron.lbaas_pools * neutron.lbaas_members * neutron.lbaas_healthmonitors * neutron.lbaas_sessionpersistences * neutron.lbaas_listener_statistics

  1. lbaas_loadbalancers
  • id - unique identifier
  • tenant_id
  • name
  • description
  • vip_port_id - the neutron port tied to the vip (this can be used to get the vip_subnet, and vip_address). This will be stored in the database but not exposed through the API.
  • vip_subnet_id - the subnet a neutron port should be created on
  • vip_address - the address of the subnet
  • provisioning_status
  • operating_status
  • admin_state_up
  • listeners - a list of back-references child listener ids
  • provider - provider in which this load balancer should be provisioned
  1. lbaas_listeners
  • id - identity
  • tenant_id
  • loadbalancer_id
  • default_pool_id - ID of default pool. Must have compatible protocol with listener.
  • protocol - Protocol to load balancer: HTTP, HTTPS, TCP, UDP
  • protocol_port - port number to listen
  • admin_state_up - admin state (True or False)
  • provisioning_status
  • operating_status

Listener model will later be amended with L7 and TLS-related attributes which are out of scope of this blueprint.

  1. lbaas_pools
  • id - identity
  • tenant_id
  • name
  • description
  • protocol - Protocol to load balance
  • lb_method - load balancing method
  • healthmonitor_id - id of health monitor
  • admin_state_up - admin state (True/False). That attribute defines administrative state of the pool on all of the backends where it is actually deployed.
  • operating_status
  1. lbaas_members
  • id - identity
  • tenant_id
  • address - ip address
  • pool_id - required parent pool
  • subnet_id - optional subnet this member is on
  • protocol_port
  • weight
  • operating_status
  • admin_state_up
  1. lbaas_healthmonitors
  • id - id
  • tenant_id
  • type - (TCP, HTTP)
  • delay
  • timeout
  • max_retries
  • http_method
  • url_path
  • expected_codes
  • admin_state_up
  1. lbaas_sessionpersistences
  • pool_id
  • type - (HTTP_COOKIE, SOURCE_IP, APP_COOKIE)
  • cookie_name
  1. lbaas_listener_statistics
  • listener_id
  • bytes_in
  • bytes_out
  • active_connections
  • total_connections

REST API Impact

A separate extension will be created exposing the following resources:

  • /lbaas/loadbalancers
  • /lbaas/listeners
  • /lbaas/pools
  • /lbaas/pools/{pool_id}/members
  • /lbaas/healthmonitors

Resource Attributes:

/lbaas/loadbalancers

CSVTable
Attribute Name Type Access Default Value Validation Conversion Description
id string (UUID) RO, all generated N/A identity
tenant_id string (UUID) RW, all (No Update) generated string tenant identity
name string RW, all ‘’ string Human-readable
description string RW, all ‘’ string Human-readable
vip_subnet_id string (UUID) RW, all (No Update) required string creates vip on this subnet
vip_address string (IP Address) RW, all (No Update) generated IPv4 or IPv6 Frontend IP address
admin_state_up bool RW, all True bool enabled
provisioning_status string RO, all N/A provisioning status  
operating_status string RO, all N/A operational status  

Deleting a load balancer will only succeed if it is not a parent of any listeners.

/lbaas/listeners

CSVTable
Attribute Name Type Access Default Value Validation Conversion Description
id string (UUID) RO, all generated N/A identity
tenant_id string (UUID) RW, all generated string tenant identity
name string RW, all ‘’ string Human-readable
description string RW, all ‘’ string Human-readable
loadbalancer_id string (UUID) RW, all (No Update) required string parent load balancer
connection_limit integer RW, all -1 integer max connections to the protocol port
protocol string RW, all (No Update) required ‘TCP’,’HTTP’,’HTTPS’ listening protocol
protocol_port integer RW, all required 0-65535 listening port
admin_state_up bool RW, all True bool enabled
provisioning_status string RO, all N/A provisioning status  
operating_status string RO, all N/A operational status  

Note that loadbalancer_id is required for now. This will not preclude later implementations that may want to allow M:N loadbalancer to listeners as this is only an API attribute and thus can be changed from required to optional.

Note that default_pool_id is not specified here as the pool will define its parent listener.

Deleting a Listener will only succeed if it is not the parent of a pool.

/lbaas/pools

CSVTable
Attribute Name Type Access Default Value Validation Conversion Description
id string (UUID) RO, all generated N/A identity
tenant_id string (UUID) RW, all generated string tenant identity
name string RW, all ‘’ string Human-readable
description string RW, all ‘’ string Human-readable
listener_id string (UUID) RW, all (No Update) required string parent listener
protocol string RW, all (No Update) required ‘TCP’,’HTTP’,’HTTPS’ protocol to send to members
lb_algorithm string RW, all required ‘ROUND_ROBIN’,’LEAST_CONNECTIONS’,SOURCE_IP load balancing algorithm
session_persistence dictionary RW, all {} type: ‘SOURCE_IP’,’HTTP_COOKIE’,’APP_COOKIE’, cookie_name: string session persistence definition
admin_state_up bool RW, all True bool enabled
operating_status string RO, all generated N/A operational status
members list RO, all generated N/A list of members belonging to this pool

Note that listener_id is required for now. There will be validation that the listener has only one pool as a child.

This should not preclude a later implementation of M:N listener to pools.

Deleting a pool will not succeed if it is the parent of a health monitor. It will however succeed if it is the parent of any children, and those children will be deleted as well.

/lbaas/pools/{pool_id}/members

CSVTable
Attribute Name Type Access Default Value Validation Conversion Description
id string (UUID) RO, all generated N/A identity
tenant_id string (UUID) RW, all generated string tenant identity
address string (IP) RW, all (No Update) required IPv4 or IPv6 IP Address member is listening
protocol_port integer RW, all required 0-65535 port member is listening
weight integer RW, all 1 integer traffic distribution weight
subnet_id string (UUID) RW, all (No Update) None string subnet to access member port
admin_state_up bool RW, all True bool enabled
operating_status string RO, all generated N/A operational status

/lbaas/healthmonitors

CSVTable
Attribute Name Type Access Default Value Validation Conversion Description
id string (UUID) RO, all generated N/A identity
tenant_id string (UUID) RW, all generated string tenant identity
type string RW, all (No Update) required ‘HTTP’,’HTTPS’,’PING’,’TCP’ type of health check
pool_id string (UUID) RW, all (No Update) required string id of pool to monitor
delay integer RW, all required integer seconds before health check
timeout integer RW, all required integer seconds for a failed check
max_retries integer RW, all required integer number of failed checks before member is considered OFFLINE
http_method string RW,all ‘GET’ ‘GET’,’POST’,’PUT’ http verb to send http checks
url_path string RW, all ‘/’ string url to send http checks
expected_codes string RW, all ‘200’ comma delimited HTTP response codes expected HTTP response codes for a successful check
admin_state_up bool RW, all TRUE bool enabled

Note that pool_id is a required attribute. Similar to listener_id on the pool object, this does not preclude later implementations of 1:M pool to health monitor relationship.

(*) denotes a required attribute

Security Impact

Standard Neutron tenant object ownership rules will apply.

Notifications Impact

None

New notifications: - loadbalancer - listener - pool - healthmonitor - member

Other End User Impact

Users may have access to a new lbaas resources. The CLI commands will be slightly different depending on which extension that is loaded.

Performance Impact

None

IPv6 Impact

None

Other Deployer Impact

LBaaS V1 and LBaaS V2 can coexist in the codebase, but should not be run at the same time. This will have to be enforced in the code.

No migration path from LBaaS V1 to V2 will be done for this blueprint, however another blueprint should do this as it will be a complicated effort.

Developer Impact

A new extension, service plugin, and driver.

Community Impact

This change has been in review since Juno. Much discussion has taken place over IRC and the mailing list.

Implementation

Assignee(s)

Primary assignees:
brandon-logan

Work Items

  • object model change
  • new loadbalancer extension for new API
  • unit tests

Dependencies

None

Testing

Functional Tests

Functional Tests for the load balancer plugin.

API Tests

All new resources added by the extension will have positive and negative tests.

Documentation Impact

User Documentation

Differences between LBaaS V1 and V2 should be documented.

Developer Documentation

There should be a new LBaaS V2 API document section documenting the new resources added by the extension.