Description

This article describes how to manage a Pool on a Network Domain in a MCP 2.0 data center location, including:

Prerequisites:

  1. Only the Primary Administrator or a User with the Network role can add a Pool on a Network Domain
  2. Data Center is MCP 2.0

  3. Recommended reading: Introduction to Virtual Listeners / VIPs in MCP 2.0

  4. Must have at least one "Advanced" Network Domain. See How to Deploy a Network Domain in a MCP 2.0 Data Center Location
    This feature is not supported on "Essentials" Network Domains.  

  5. It is important to note that a Pool can have up to 100 associated Nodes.

Content / Solution:

  1. From the Home page, select the Data Center where the MCP 2.0 Network Domain on which you want to manage a Pool is located:


  2. The Data Center Dashboard will be displayed. Click on the Advanced Network Domain where you want to manage the Pool:


  3. The Network Domain dashboard will be displayed:
     

Edit Pool

  1. Click on the Load Balancing / Virtual IPs tab, then click on the Manage gear for the Pool you want to edit and select Edit Pool from the dropdown menu:

    Note: The Pool you want to manage may be in the Unassigned Pools folder if it has not yet been assigned to a Virtual Listener.

  2. The Edit Pool dialog will be displayed:

    Note: The Name of the Pool cannot be edited.
     
  3. Fill out the form with the requested information:

    • Description - The optional Description is limited to a maximum length of 255 characters.
    • Health Monitor 1 & 2 - Procedure that the system uses to check whether or not the Pool is "healthy". The same Health Monitor cannot be specified for both fields.
      • CCDEFAULT.Http - The HTTP monitor performs a simple "GET /" on the port specified on the pool member and returns successfully if any content is returned.
      • CCDEFAULT.Tcp - The default TCP monitor considers a node healthy if the full TCP handshake can be completed.
      • CCDEFAULT.TcpHalfOpen - A TCP Half Open type of monitor performs a quick check on the associated service by sending a TCP SYN packet to the service. As soon as the monitor receives the SYN-ACK packet from the service, the monitor considers the service to be in an up state, and sends a RESET to the service instead of completing the three-way handshake.
      • CCDEFAULT.Udp - The User Datagram Protocol (UDP) health monitor is designed to work with ICMP Destination Unreachable message responses. When the load balancer sends a UDP health monitor request to the host (pool member) and the host's UDP port is unavailable, the monitored host returns an ICMP port unreachable message in response to the monitor request, and the load balancer immediately marks the resource down. If the monitored host goes down (for example, due to a crash or reboot), the host fails to send the ICMP port unreachable messages back to the load balancer, and the host remains marked up. For this reason, it is recommended that you use the UDP monitor in conjunction with a secondary monitor. 
    • Load Balancing Method - Defines how the Pool will handle load balancing. 
      • Round Robin - Round Robin mode passes each new connection request to the next server in line, eventually distributing connections evenly across the array of machines being load balanced.
      • Least Connections Member - This method sends a new connection to the member of a Pool which has the least amount of connections at the exact moment that the connection is initiated. Only connections that exist to that member that are being handled by this Pool are considered.
      • Least Connections Node -  This method sends a new connection to the member of a Pool which has the least amount of connections at the exact moment that the connection is initiated; all connections to that Node, regardless of which Virtual Listener is handling the traffic, counts towards the connection count.
      • Observed Member - Specifies that the system ranks members based on the number of connections. Nodes that have a better balance of fewest connections receive a greater proportion of the connections. This method differs from Least Connections (member), in that the Least Connections method measures connections only at the moment of load balancing, while the Observed method tracks the number of Layer 4 connections to each Node over time and creates a ratio for load balancing. This dynamic load balancing method works well in any environment, but may be particularly useful in environments where Node performance varies significantly.
      • Observed Node - Specifies that the system ranks Nodes based on the number of connections. Nodes that have a better balance of fewest connections receive a greater proportion of the connections. This method differs from Least Connections (Node), in that the Least Connections method measures connections only at the moment of load balancing, while the Observed method tracks the number of Layer 4 connections to each Node over time and creates a ratio for load balancing. This dynamic load balancing method works well in any environment, but may be particularly useful in environments where Node performance varies significantly.
      • Predictive Member - Uses the ranking method used by the Observed (member) methods, except that the system analyzes the trend of the ranking over time, determining whether a Node's performance is improving or declining. The Nodes in the pool with better performance rankings that are currently improving, rather than declining, receive a higher proportion of the connections. This dynamic load balancing method works well in any environment.
      • Predictive Node - Uses the ranking method used by the Observed (member) methods, except that the system analyzes the trend of the ranking over time, determining whether a Node's performance is improving or declining. The Nodes in the pool with better performance rankings that are currently improving, rather than declining, receive a higher proportion of the connections. This dynamic load balancing method works well in any environment.
    • Action on Service Down - When a Pool Member fails to respond to a Health Monitor, the system marks that Pool Member down and removes any persistence entries associated with the Pool Member. The BIG-IP system continues to monitor the Pool Member to determine when the Member becomes available again. While a Pool Member is marked down, the system does not send any new connections to that Pool Member. The Action On Service Down feature specifies how the system should respond to already-established connections when the target Pool Member becomes unavailable.
    • Slow Ramp Time - This allows a Server to slowly ramp up connections. The Slow Ramp Time feature (enabled by default) is used to slowly increase the number of connection requests that are load balanced to a new Pool Member. The Slow Ramp Time setting controls the percentage of connections that are sent to a new Pool Member by specifying the duration (in seconds), that a Pool Member is in slow ramp mode. For example, if the Slow Ramp Time setting is set to 10 seconds (the default setting), when a newly enabled Pool Member has been available for one second, the system begins load balancing 1/10 of the connections that would have been sent to the new Pool Member had the Slow Ramp Time setting been disabled. Each second thereafter, the system increases the amount of traffic load balanced to the new Pool Member. So, after the Pool Member has been available for nine seconds, the system is load balancing 90 percent of the normal load to that Pool Member. When the Pool Member has been available for longer than the Slow Ramp Time value, the Pool Member receives its full proportion of the incoming traffic. Should be an integer between 1 and 120 (measured in seconds). The default is 10. 

      For information on Health Monitors, see: Introduction to Health Monitors at an MCP 2.0 Data Center 

      Note: There is a relationship between the presence of Health Monitors on a Pool and the settings of its Pool Members; for details please refer to: How to Add a Node as a Pool Member
       
  4. Once the Edit Pool form has been filled out, click the Save button:


  5. The system will display a success message:

     

  6. The edits will be applied and the UI will be updated to reflect the changes: 
     

Add New Nodes to Pool

  1. Click on the Load Balancing / Virtual IPs tab, then click on the Manage gear for the Pool you want to manage and select 'Add new Nodes to Pool' from the dropdown menu:


  2. The Create Nodes form will be displayed:

    Note: See How to Create a Node on a Cloud Network Domain for further details on creating a Node. 
     

  3. Once the Create Nodes form has been filled out, click the Create button:

    Note: If you choose to create a Node with a Health Monitor, you will have to edit the Pool Member settings:

      • Port - Enter the Port you would like the Pool Member to be associated with. 

      • Pool Member Status - Select an initial Status for the Pool Member from the dropdown menu.
        • Enabled - Permits traffic.
        • Disabled - Continues to process persistent and active connections. It can accept new connections only if the connections belong to an existing persistence session.
        • Forced Offline - Allows existing connections to time out, but no new connections are allowed.
           
  4. The system will display a success message:


  5. The new Node will be added to the Pool and the UI will be updated to reflect the change:

Add Existing Nodes to Pool

  1. Click on the Load Balancing / Virtual IPs tab, then click on the Manage gear for the Pool you want to manage and select 'Add existing Nodes to Pool' from the dropdown menu:


  2. The Add Existing Nodes to Pool dialog will be displayed:

    Note: The form will be pre-populated with the name of the Pool to which you want to add an existing Node. 

  3. Fill out the form by selecting the desired Node from the dropdown menu, then click Add Nodes:
     

    Note: You can use the  button to add multiple existing Nodes to a Pool:

    Note: If the Pool has a Health Monitor, you will need to enter a port in the Pool Member Settings section.
    If the Pool does not have a Health Monitor, you can select 'Any' port or select a specific Port.

  4. The system will display a success message:


  5. The Node will be added to the Pool and the UI will be updated to reflect the change:

Delete Pool

  1. Click on the Load Balancing / Virtual IPs tab, then click on the Manage gear for the Pool you want to delete and select Delete Pool from the dropdown menu:


  2. The Delete Pool confirmation dialog will be displayed. Click Delete:


  3. The system will display a success message:

     

  4. The Pool will be deleted and the UI will be updated to reflect the change:
     

    Note: Any Nodes that were assigned solely to the deleted Pool will be placed in the Unassigned Nodes folder.