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Overview

Octavia provides network load balancing for OpenStack and is the reference implementation LBaaS (Load Balancer as a Service). Since the OpenStack Liberty release, Octavia has fully replaced and has become the reference implementation for Load Balancing as a Service (LBaaS v2).

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Status	Reason
ONLINE	Entity is operating normally. All Pool members are healthy
DRAINING	Member is not accepting new connections
OFFLINE	Entity is administratively disabled
DEGRADED	One or more components are in ERROR
ERROR Please refer to error messages	Entity has failed. Member is failing health monitoring check. All pool members are in ERROR
NO_MONITOR	No health monitor is configured. Current status in known

References

https://docs.openstack.org/octavia/train/reference/introduction.html

https://docs.openstack.org/octavia/train/user/guides/basic-cookbook.html

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Load Balancer as a Service Quick Start

This quick start assumes you have a VM set up with SSH and a webserver that you want to expose. The steps included are applicable to other ports and services too. This example assumes you’ve configured your machine following Running an NGinX webserver inside a Docker container. The steps will be similar for bespoke systems too.

First we will create a load balancer and use it to provide ssh access to a VM initially, then add another listener and pool to point to the webserver on the VM.

Create a Loadbalancer

In the Openstack web interface, expand Network and then click Load Balancers on the left hand side of the screen.

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Click “Create Load Balancer”

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On the “Load Balancer Details” screen enter a name for the load balancer and select the subnet for your projects private network. Leave the IP Address and Flavor fields blank. Then click “Next”

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On the “Listener Details” screen select Protocol TCP and set port 200 (which we’ve randomly selected). To avoid conflicts it’s best to select random port numbers greater than 1024. Enter the name as ssh. The other defaults are fine. Click “Next”

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On the “Pool Details” screen enter the name as SSH and set the Algorithm and Session Persistence to “Source IP”. Click “Next”

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On the “Pool Members” screen add the VM you want to point at and set the port to 22. Click “Next”

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On the “Monitor Details” screen enter the name ssh and set the type to “TCP”. Click “Create Load Balancer”

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You will then see the loadbalancer that you created in the list with the Provisioning Status of “Pending Create”

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After a few minutes the Provisioning Status will be updated to “Active”

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Now Click the arrow next to “Edit Load Balancer” and click “Associate Floating IP”

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Select one of your floating IPs and then click “Associate”

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You should now be able to ssh to your VM on port 200 of the IP you assigned to the load Balancer

Code Block
ssh username@130.246.215.87 -p 200

Viewing details

If you click on the Name of the load balancer you can view details of the listerners and pools

Unfortunately a number of the “Operating Status” fields always report “Offline” even when they are online

You can add another Listener to this load balancer by hitting “Create Listener” and following similar steps to the above :ref: create_octavia_listener

Try using these steps to load balance access to the nginx webserver created in the other tutorial.

Explanation of terms

Algorithms:

Least connections - sends each connection to whichever pool member has the

Round Robin - sends connections to each backend node in return

Source IP - Sends connections to backend nodes based on the hash of the client’s IP

Session Persistence:

Source IP - Uses the hash of the client’s IP to maintain session persistence

HTTP Cookie - Session persistence based on http cookies

APP Cookie - Session persistence based on application cookies

Monitor Types:

HTTP - Checks for a configurable http response

HTTPS - Checks for a http 200. Requires that the certificate is trusted by the loadbalancer and we currently dont have a way to inject new CAs

PING - A simple ping test

TCP - A simple tcp handshake

TLS-HELLO - A tls handshake

UDP-CONNECT - Checks for an open udp socket.

LBaaS v2: Heat Stacks

Load balancing in a template consists of:

Pool: A group of servers which are identified by their floating IP addresses. The size of the pool can be increased or decreased in response to traffic to the instances detected by the load balancer.
Listener: Represent a listening endpoint for the vip. Listener resources listen for the client traffic.
Health Monitor: Monitors the health of the pool.
Load Balancer: Balances the traffic to server pools. In combination with the health monitor and listener, the load balancer can redistribute traffic to servers in the event of one server failing for example.

Octavia Resources in Heat

Code Block

pool:
  type: OS::Octavia::Pool
  properties:
    ## required ##########
    lb_algorithm: String #algorithm to distribute the load between the members of the pool: ROUND_ROBIN, LEAST_CONNECTIONS, SOURCE_IP
    protocol: String #protocol of the pool: TCP, HTTP, HTTPS, TERMINATED_HTTPS, SOURCE_IP

    ## optional ##########
    admin_state_up: Boolean #the administrative state of the pool
    description: String #description of the pool
    listener: String #listener name/ID to be associated with the pool
    loadbalancer: String #the loadbalancer name/ID to be associated to the pool
    name: String #name of this pool
    session_persistence: {"type": String, "cookie_name": String} #configuration of session persistence.
      #required - type: the method of session persistence feature: SOURCE_IP, HTTP_COOKIE, APP_COOKIE
      #optional - cookie_name: name of the cookie - required if type is APP_COOKIE
    tls_enabled: Boolean #default - false. Enable backend member re-encryption

listener:
  type: OS::Octavia::Listener
  properties:
    ## required ############
    protocol: String # protocol on which to listen for client traffic: TCP, HTTP, HTTP/S, TERMINATED_HTTPS, PROXY, UDP
    protocol_port: Integer # TCP or UDP Port on which to listen for client traffic

    ## optional ############
    admin_state_up: Boolean
    allowed_cidrs: [String, String, ...]
    connection_limit: Integer
    default_pool: String
    default_tls_container_ref: String
    description: String
    loadbalancer: String
    name: String
    sni_container_refs: [Value, Value, ...]
    tenant_id: String

health_monitor:
  type: OS::Octavia::HealthMonitor
  properties:
    ## required properties ############
    delay: Integer #(seconds) minimum time between regular connections of pool member
    max_retries: Integer # max number of permissible connection failures before changing member status to INACTIVE
    pool: String #name/ID of load balancing pool (type: octavia.pool)
    timeout: Integer # maximum number of seconds for a monitor to wait for a connection to be established before timeout.
    type: String #type of health monitor: PING, TCP, HTTP, HTTPS, UDP-CONNECT
    ## Optional ##############
    admin_state_up: Boolean #(default: true) administrative state of a health monitor.
    expected_codes: String #expected HTTP codes for a healthy monitor e.g. a single value (200), a list (200,202), or a range (202-204)
    http_method: String #method used for requests by HTTP monitor
    tenant_id: String #ID of tenant which owns the monitor
    url_path: String #HTTP path used in the HTTP request used by the monitor to test a member's health

load_balancer:
  type: OS::Octavia::LoadBalancer
  properties:
    ## required ############
    vip_subnet: String #name/ID of the subnet on which to allocate the VIP address
    ## optional ############
    admin_state_up: Boolean #administrative state of the load balancer (default: true)
    description: String #description of the load balancer
    flavor: String #name/id of the flavor of the load balancer
    name: String #name of the loadbalancer
    provider: String #the provider of this load balancer
    tenant_id: String #id of the tenant which owns the loadbalancer
    vip_address: String #IP address for the VIP

The table below lists the attributes for each resource:

Code Block

| Resource                          | Attributes
|-----------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| OS::Octavia::LoadBalancer         | **flavor_id:** The flavor ID of the LoadBalancer<br><br>**pools:** the pools this LoadBalancer is associated with<br><br>**show:** detailed       information about the resource<br><br>**vip_address:** the VIP addresses of the LoadBalancer<br><br>**vip_port_id:** the VIP port of the LoadBalancer<br>           <br>**vip_subnet_id:** the VIP subnet of LoadBalancer   |
| OS::Octavia::Pool                 | **healthmonitor_id:** the ID of the health monitor associated with this pool<br><br>**listeners:** listener associated with this pool <br><br>**members:** members associated with this pool<br><br>**show:** detailed information about resource                                                                                                             |
| OS::Octavia::HealthMonitor        | **pool:** the list of pools related to this monitor<br><br>**show:** detailed information about the resource                                                                                                                                                                                                                                                  |
| OS::Octavia::Listener             | **default_pool_id:** ID of the default pool the listener is associated to<br><br>**loadbalancers:** the ID of the load balancer this listener     is associated to<br><br>**show:** detailed information about resource                                                                                                                                               |

Example

The example below shows how the Octavia resources can be defined in a Heat Template.

Code Block

#HTTP health monitor
health_monitor:
  type: OS::Octavia::HealthMonitor
  properties:
    delay: 3 #three second delay
    type: "HTTP"
    timeout: 3 # seconds
    max_retries: 3
    pool: {get_resource: pool}
    url_path: /healthcheck #this is a URL path that is configured on the servers in the pool that the monitor can reach to check pool health.

pool:
  type: OS::Octavia::Pool
  properties:
    lb_algorithm: "LEAST_CONNECTIONS" #the preferred algorithm
    protocol: "HTTP"
    listener: {get_resource: listener}

member:
  type: OS::Octavia::PoolMember
  properties:
    address: {get_attr: [server, first_address]}
    pool: {get_resource: pool}
    protocol_port: 80
    subnet: {get_param: private_subnet}

listener:
  type: OS::Octavia::Listener
  properties:
    protocol: "HTTP"
    protocol_port: 80 # listen on the HTTP port
    loadbalancer: {get_resource: lb}

lb:
  #define the load balancer and the private subnet to use
  type: OS::Octavia::LoadBalancer
  properties:
    vip_subnet: <private-subnet-id>

# Attach a floating IP to the load balancer
floating_ip_association:
  # Associate a floating IP to the Load Balancer so that it can be accessed
  # using an external IP
  type: OS::Neutron::FloatingIPAssociation
  properties:
    floatingip_id: <floating-ip-id>
    port_id: {get_attr: [lb,vip_port_id]}