Advanced Features

Control the VM Placement

By default, VMs are placed by NOVA using its own scheduling logic. However, traffic can be shaped precisely to fill the appropriate network links by using specific configuration settings. KloudBuster can change that behavior, and force NOVA to place VMs on desired hypervisors as we defined by supplying the topology file.

The format of the topology file is relatively simple, and group into two sections. See file “cfg.topo.yaml” for an example.

The “servers_rack” section contains the hypervisors that the server side VMs will be spawned on, and the “clients_rack” section contains the hypervisors that the client side VMs will be spawned on. The hypervisor names can be obtained from Horizon dashboard, or via “nova hypervisor-list”. Note that the name in the config files must exactly match the name shown in Horizon dashboard or NOVA API output.

A typical use case is to place all server VMs on one rack, and all client VMs on the other rack to test Rack-to-Rack performance. Similarly, all server VMs on one host, and all client VMs on the other host to test the Host-to-Host performance.

To use this feature, just pass -t <path_to_topo_file> to the kloudbuster command line.


Admin access is required to use this feature.

Interactive mode

When using the CLI, the “–interactive” option allows to re-run the workloads any number of times from the prompt after the resources are staged. This is useful for example to avoid restaging after each run.

Running KloudBuster without admin access

When there is no admin access to the cloud under test, KloudBuster does support to run and reused the existing tenant and user for running tests. You have to ask the cloud admin one time to create the resources in advance, and KloudBuster will create the resources using the pre-created tenant/user.

When running under the tenant/user reusing mode:

  • Only one tenant will be used for hosting both server cloud and client cloud resources;
  • Only two users will be used for creating resources, and each cloud has its own user;

And also there are some limitations that you should aware:

  • The VM placement feature will not be supported;
  • The flavor configs will be ignored, and the KloudBuster will automatically pick the closest flavor settings from the existing list;
  • KloudBuster will not automatically adjust the tenant quota, and give warnings when quota exceeded;

See file “cfg.tenants.yaml” for an example. Modify the settings to match your cloud.

To use this feature, just pass -l <path_to_tenants_file> to the kloudbuster command line.

Displaying the Results

Results can be saved in a file in json format or in HTML format. The json format is more appropriate for usage by any post-processing tool or script while the HTML file is more adapted for human usage.

The KloudBuster Web UI will display the results using charts and tables when the test is finished running. The KloudBuster CLI provides an option to generate the HTML file from the results (–html option). It can also generate the HTML file from the JSON results (–charts-from-json option).

Examples of running KloudBuster

Assuming the OpenStack RC file is stored at ~/, and the password is “admin”. Running the program is relatively easy, some examples are given to help get started quickly.


Before going to large scale test, it is strongly recommended to start with a small scale. The default config is a good point to start with. It will make sure KloudBuster is talking to the clouds well.

Example 1: HTTP Scale, Single-cloud Mode

Kloudbuster will create both server VMs and client VMs in the same cloud if only one RC file is provided:

$ kloudbuster --rc ~/ --passwd admin

Example 2: HTTP Scale, Dual-cloud Mode, Save results

Assume the cloud for server VMs is ~/, and the cloud for client VMs is ~/ The password for both clouds is “admin”. Also save the results to a JSON file once the run is finished:

$ kloudbuster --rc ~/ --passwd admin --testing-rc ~/ --testing-passwd admin --json result.json

Example 3: HTTP Scale, Single-cloud Mode, Customized VM placements

$ kloudbuster --rc ~/ --passwd admin -t cfg.topo.yaml

Example 4: Storage benchmark, Save results to JSON

$ kloudbuster --rc ~/ --passwd lab --storage --json aio.json