You can change the properties of an origin-server pool by using either the administration console or the CLI.
Note:
When you modify an origin-server pool, you are, in effect, modifying a configuration. So for the updated origin-server pool settings to take effect in the Oracle Traffic Director instances, you should redeploy the configuration as described in Section 4.3, "Deploying a Configuration."
The CLI examples in this section are shown in shell mode (tadm>). For information about invoking the CLI shell, see Section 2.3.1, "Accessing the Command-Line Interface."
Changing the Properties of an Origin-Server Pool Using the Administration Console
To change the properties of an origin-server pool by using the administration console, do the following:
Log in to the administration console, as described in Section 2.3.2, "Accessing the Administration Console."
Click the Configurations button that is situated at the upper left corner of the page.
A list of the available configurations is displayed.
Select the configuration for which you want to modify origin-server pools.
In the navigation pane, select Server Pools.
The Origin Server Pools page is displayed. It shows a list of the origin-server pools that are defined for the configuration.
Click the name of the origin-server pool that you want to modify.
The Origin Server Pool Settings page is displayed. On this page, you can do the following:
Change the network protocol—IPv4, IPv6, or SDP—for the servers in the pool.
Set a proxy server via the Connect to Origin Servers via Proxy Server section. This setting specifies a HTTP forward proxy server to be associated with an origin server pool so that all member origin servers of the pool are communicated with via the configured HTTP forward proxy server.
Change the load-balancing method that Oracle Traffic Director should use to distribute client requests to the pool.
Least connection count (default): When processing a request, Oracle Traffic Director assesses the number of connections that are currently active for each origin server, and forwards the request to the origin server with the least number of active connections.
The least connection count method works on the premise that origin servers that are faster have fewer active connections, and so can take on more load. To further adjust the load distribution based on the capacities of the origin servers, you can assign relative weights to the origin servers.
Note:
WebSocket connections affect the least connection count load balancing algorithm because WebSocket connections are potentially long lasting and will be counted as active connections until they are closed.Least response time: Though least connection count works well on most workloads, there could be situations when the response time of origin servers in a given pool for the same amount of load could differ. For example:
- When origin servers of a given pool are deployed on machines that differ in hardware specification.
- When some origin server nodes are used for other services.
- When network connectivity for different nodes is not uniform or some network interfaces are more loaded than others.
Least response time is useful in such scenarios because it is a dynamic weighted least connection algorithm and it calculates weights based on the response time. These weights are continuously adjusted based on how the origin servers respond. Least response time helps you avoid manual tuning of weights in the least connection algorithm.
Round robin: Oracle Traffic Director forwards requests sequentially to the available origin servers—the first request to the first origin server in the pool, the second request to the next origin server, and so on. After it sends a request to the last origin server in the pool, it starts again with the first origin server.
Though the round-robin method is simple, predictable, and low on processing overhead, it ignores differences in the origin servers' capabilities. So, over time, requests can accumulate at origin servers that are significantly slow. To overcome this problem, you can use a weighted round-robin method, by assigning relative weights to the origin servers.
For more information about assigning weights to origin servers, see Section 7.3, "Modifying an Origin Server."
Configure health-check settings. For more information, see Section 14.3, "Configuring Health-Check Settings for Origin-Server Pools."
Specify whether Oracle Traffic Director should dynamically discover Oracle WebLogic Server managed servers in a cluster. For more information, see Section 6.5, "Configuring an Oracle WebLogic Server Cluster as an Origin-Server Pool."
Note:
You can add, modify, and remove origin servers in the pool, by selecting Origin Servers in the navigation pane. For more information, see Chapter 7, "Managing Origin Servers."Specify the parameters that you want to change.
On-screen help and prompts are provided for all of the parameters.
When you change the value in a field or tab out of a text field that you changed, the Save button near the upper right corner of the page is enabled.
At any time, you can discard the changes by clicking the Reset button.
After making the required changes, click Save.
A message, confirming that the updated configuration was saved, is displayed in the Console Messages pane.
In addition, the Deployment Pending message is displayed at the top of the main pane. You can either deploy the updated configuration immediately by clicking Deploy Changes, or you can do so later after making further changes as described in Section 4.3, "Deploying a Configuration."
Changing the Properties of an Origin-Server Pool Using the CLI
To change the network protocol and load-balancing method for an origin-server pool, run the set-origin-server-pool-prop command.
For example, the following command changes the load-balancing method for the origin-server pool osp1 in the configuration soa to the round-robin method.
tadm> set-origin-server-pool-prop --config=soa --origin-server-pool=osp1 load-distribution=round-robin OTD-70201 Command 'set-origin-server-pool-prop' ran successfully.
To change the health-check parameters for an origin-server pool, run the set-health-check-prop command.
For example, the following command changes the health-check ping interval for servers in the origin-server pool osp1 of the configuration soa to 60 seconds.
tadm> set-health-check-prop --config=soa --origin-server-pool=osp1 interval=60 OTD-70201 Command 'set-origin-server-pool-prop' ran successfully.
For the updated configuration to take effect, you should deploy it to the Oracle Traffic Director instances by using the deploy-config command.
For a list of the properties that you can set or change by using the set-origin-server-pool-prop and set-health-check-prop commands, see the Oracle Traffic Director Command-Line Reference or run the command with the --help option.