Managing balancing pools

To see a list of balancing pools in a load balancer, click its name.

You can open the pool right pane to monitor its performance and health on the Overview tab, see its parameters on the Properties tab, manage its members on the Members tab, and configure its allowed IP ranges on the CIDRs tab.

Limitations

  • The forwarding rule and protocol cannot be changed after the load balancer pool is added.

Prerequisites

  • All VMs that will be added in balancing pools have fixed IP addresses.

To add another balancing pool to a load balancer

  1. On the screen with balancing pools, click Create balancing pool.

  2. In the Forwarding rule section, select a forwarding rule from the load balancer to the backend protocol:

      1. Specify ports for incoming and destination connections.
      2. Ensure that all virtual machines have the same SSL certificate (or a certificate chain).

      3. Enable the PROXY protocol version 1 to add a human-readable header with connection information (the source IP address, destination IP address, and port numbers) as a part of the request header.

      1. Specify ports for incoming and destination connections.
      2. Upload an SSL certificate (or a certificate chain) in the PEM format and a private key in the PEM format.

      3. Choose HTTP headers to insert into the request.

      4. Enable the TLS encryption to re-encrypt traffic from the load balancer to its members.

      5. Enable the PROXY protocol version 1 to add a human-readable header with connection information (the source IP address, destination IP address, and port numbers) as a part of the request header.

      1. Specify ports for incoming and destination connections.

      2. Choose HTTP headers to insert into the request.

      3. Enable the TLS encryption to re-encrypt traffic from the load balancer to its members.

      4. Enable the PROXY protocol version 1 to add a human-readable header with connection information (source IP address, destination IP address, and port numbers) as a part of the request header.

      1. Specify ports for incoming and destination connections.

      2. Enable the TLS encryption to re-encrypt traffic from the load balancer to its members.

    • Specify ports for incoming and destination connections.

  3. In the Balancing settings section, do the following:

    1. Select the balancing algorithm:

      • Least connections. Requests will be forwarded to the VM with the least number of active connections.
      • Round robin. All VMs will receive requests in the round-robin manner.
      • Source IP. Requests from a unique source IP address will be directed to the same VM.

    2. Select Sticky session to enable session persistence. The load balancer will generate a cookie that will be inserted into each response. The cookie will be used to send future requests to the same VM.

      This option is not available in the SSL passthrough mode.

  4. In the Members section, add members, that is, virtual machines, to the balancing pool by clicking Add. Each VM can be included to multiple balancing pools. In the Add members window that opens, select the desired VMs, and then click Add.

    You can select only between VMs that are connected to the chosen network.

  5. In the Allowed CIDRs section, specify IP address ranges in the CIDR format that will be allowed to interact with the balancing pool. This will limit incoming traffic to the specified IP addresses, any other incoming traffic will be rejected. For example:

    • To limit traffic from the IP address 10.10.10.10, add the /32 suffix: 10.10.10.10/32.
    • To limit traffic from the subnet range 10.10.10.0–10.10.10.255, add the /24 suffix: 10.10.10.10/24.
    • To limit traffic from the subnet range 10.10.0.0 - 10.10.255.255, add the /16 suffix: 10.10.10.10/16.

  6. In the Health monitor section, select the protocol that will be used for monitoring members availability:

    • HTTP/HTTPS. The HTTP/HTTPS method GET will be used to check for the response status code 200. Additionally, specify the URL path to the health monitor.
    • TCP/UDP. The health monitor will check the TCP/UDP connection on the backend port.
    • PING. The health monitor will check members’ IP addresses.

    By default, the health monitor removes a member from a balancing pool if it fails three consecutive health checks of five-second intervals. When a member returns to operation and responds successfully to three consecutive health checks, it is added to the pool again. You can manually set the health monitor parameters, such as the interval after which VM health is checked, the time after which the monitor times out, healthy and unhealthy thresholds. To change the default parameters, click Edit parameters, enter the desired values, and then click Save.

  7. Click Create.

The newly added pool will appear in the list of balancing pools.

To edit a balancing pool

  1. On the screen with balancing pools, click the required balancing pool.

  2. On the right pane, click one of the following:

    • To edit the balancing settings such as the HTTP headers, TLS encryption, balancing algorithm, and session persistence, click Edit.
    • To add or remove IP ranges that are allowed to interact with the balancing pool, click Edit allowed CIDRs.
    • To edit the health monitor parameters, click Edit health monitor.

To add more members to a balancing pool

  1. On the screen with balancing pools, click the required balancing pool.
  2. On the right pane, click + Add members.
  3. In the Add members window, select virtual machines to be added to the balancing pool, and then click Add.

To remove a balancing pool

  1. Click the ellipsis icon next to the required balancing pool, and then click Delete.
  2. Click Delete in the confirmation window.