You can add a server pool to manage and share backend servers flexibly and efficiently. A pool manages load balancer distribution methods and has a service monitor attached to it for health check parameters.

Procedure

  1. Open Edge Gateway Services.
    1. Navigate to Networking > Edges.
    2. Select the edge gateway to edit, and click Configure Services.
  2. Navigate to Load Balancer > Pools.
  3. Click the Create (Create button) button.
  4. Type a name and, optionally, a description for the load balancer pool.
  5. Select a balancing method for the service from the Algorithm drop-down menu:

    Option

    Description

    ROUND-ROBIN

    Each server is used in turn according to the weight assigned to it. This is the smoothest and fairest algorithm when the server processing time remains equally distributed.

    IP-HASH

    Selects a server based on a hash of the source and destination IP address of each packet.

    LEASTCONN

    Distributes client requests to multiple servers based on the number of connections already open on the server. New connections are sent to the server with the fewest open connections.

    URI

    The left part of the URI (before the question mark) is hashed and divided by the total weight of the running servers. The result designates which server will receive the request. This option ensures that a URI is always directed to the same server as long as the server does not go down.

    HTTPHEADER

    HTTP header name is looked up in each HTTP request. The header name in parenthesis is not case sensitive which is similar to the ACL 'hdr()' function. If the header is absent or does not contain any value, the round robin algorithm is applied. The HTTP HEADER algorithm parameter has one option headerName=<name>. For example, you can use host as the HTTP HEADER algorithm parameter.

    URL

    URL parameter specified in the argument is looked up in the query string of each HTTP GET request. If the parameter is followed by an equal sign = and a value, then the value is hashed and divided by the total weight of the running servers. The result designates which server receives the request. This process is used to track user identifiers in requests and ensure that a same user ID is always sent to the same server as long as no server goes up or down. If no value or parameter is found, then a round robin algorithm is applied. The URL algorithm parameter has one option urlParam=<url>.

  6. Add members to the pool.
    1. Click the Add (Create button) button.
    2. Enter the name for the pool member.
    3. Enter the IP address of the pool member.
    4. Enter the port at which the member is to receive traffic from the load balancer.
    5. Enter the monitor port at which the member is to receive health monitor requests.
    6. In the Weight text box, type the proportion of traffic this member is to handle. Must be an integer in the range 1-256.
    7. (Optional) In the Max Connections text box, type the maximum number of concurrent connections the member can handle.

      When the number of incoming requests exceeds the maximum, requests are queued and the load balancer waits for a connection to be released.

    8. (Optional) In the Min Connections text box, type the minimum number of concurrent connections a member must always accept.
    9. Click Keep to add the new member to the pool.

      The operation can take a minute to complete.

  7. (Optional) To make client IP addresses visible to the back end servers, select Transparent.

    When Transparent is not selected (the default value), back end servers see the IP address of the traffic source as the internal IP address of the load balancer.

    When Transparent is selected, the source IP address is the actual IP address of the client and the edge gateway must be set as the default gateway to ensure that return packets go through the edge gateway.

  8. Click Keep to preserve your changes.

    The operation can take a minute to complete.

What to do next

Add virtual servers for your load balancer. A virtual server has a public IP address and services all incoming client requests. See Add a Virtual Server.