# Configuration¶

## Hosts¶

Tenks uses Ansible inventory to manage hosts. A multi-host setup is therefore supported, although the default hosts configuration will deploy an all-in-one setup on the host where the ansible-playbook command is executed (localhost).

• Configuration management of the Tenks cluster is always performed on localhost.

• The hypervisors group should not directly contain any hosts. Its sub-groups must contain one or more system. Systems in its sub-groups will host a subset of the nodes deployed by Tenks.

• The libvirt group is a sub-group of hypervisors. Systems in this group will act as hypervisors using the Libvirt provider.

## Variable Configuration¶

A variable override file should be created to configure Tenks. Any variables specified in this file will take precedence over their default settings in Tenks. This will allow you to set options as necessary for your setup, without needing to directly modify Tenks’ variable files. An example override file can be found in ansible/override.yml.example.

Most of the configuration you will need to do relates to variables defined in ansible/host_vars/localhost. You can set your own values for these in your override file (mentioned above). In addition to other options, you will need to define the types of node you’d like to be able to manage as a dict in node_types, as well as the desired deployment specifications in specs. Format and guidance for available options will be found within the variable file.

Broadly, most variables in ansible/group_vars/* have sensible defaults which may be left as-is unless you have a particular need to configure them. A notable exception to this is the variable physnet_mappings in ansible/group_vars/hypervisors, which should map physical network names to the device to use for that network: this can be a network interface, or an existing OVS or Linux bridge. If these mappings are the same for all hosts in your hypervisors group, you may set a single dict physnet_mappings in your overrides file, and this will be used for all hosts. If different mappings are required for different hosts, you will need to individually specify them in an inventory host_vars file: for a host with hostname myhost, set physnet_mappings within the file ansible/inventory/host_vars/myhost.