Creating resource inventories for Schematics actions

A resource inventory defines a single IBM Cloud resource or a group of resources where you want to run Ansible playbooks, modules, or roles by using Schematics actions.

You can specify your resource inventory by using a static inventory file, or dynamically retrieve target IBM Cloud resources from Schematics workspaces.

Creating static inventory files

Schematics supports the definition of hosts.ini files where you specify a single target host or a group of target hosts using their IP address. You can assign names to a group of target hosts, such as [webserver], and use this name in your Ansible playbook to instruct Schematics where to run the playbook tasks.

Defining static hosts

To connect to a target host through SSH, Ansible requires either a DNS resolvable hostname or an IP address.

Typical usage of Schematics actions to configure VSI's on IBM Cloud is through a bastion host. See actions documentation. Access to the private network interface of a VSI is through a bastion host. This means using the hosts private IP address to connect to the target host, as private host names are not advertised by DNS to Schematics. For private hosts, inventory must be configured with an IP address and the IP address of a bastion host.

VSI's with public IP addresses and publicly registered DNS host names can be referenced by fully qualified DNS host names.

The use of (short form) hostnames is not supported.

Creating the host file

Log in to IBM Cloud console.
Click the Menu icon > Platform Automation > Schematics > Ansible.
Click the playbook name.
Click Inventory > Create Inventory.
Enter a name for your inventory, verify your location, and select your Resource group where you want to create an inventory.
Select the Define manually tab.
In the File field, enter the target hosts where you want to run the Ansible playbook. Make sure to specify your hosts in an INI syntax. For a sample syntax, see File format. Review the limitations to ensure that your inventory definition is supported in Schematics.
Click Create inventory.
Follow the steps to create a Schematics actions and use the resource inventory that you created.

File format

Review the following sample hosts.ini file to see the structure of the static host inventory list. For more information about hosts.ini file structures, see Ansible documentation.

This example references both publicly accessible hosts through host name and private hosts through IP address.

```text {: screen}
mail.example.com

[webservers]
web1.mydomain.com
web2.mydomain.com

[dbservers]
172.16.5.9
172.16.5.10
172.16.5.11

[datacenters]
172.15.4.0
```

Limitations

Review the following limitations of static inventory files in Schematics:

Schematics supports only the INI file syntax.
Variables are not supported in hosts.ini files.
Specifying host groups by using key-value pairs in hosts.ini files is not supported.
You must manually update the hosts.ini file if hostname or IP address of target hosts change.
Where hosts are secured by a bastion host and only accessible through private IP address, the IP address of the host must be specified.
Where hosts are accessible through a publicly accessible IP address and have a registered DNS name, the host can be referenced by its fully qualified host name.
All target hosts must be configured with the same public SSH key. When you use the static inventory file in your Schematics action, you can specify one SSH key to authenticate with all target hosts that are included in your resource inventory. The SSH key should contain \n at the end of the key details in case of command-line or API calls. For more information about SSH keys, see Adding an SSH key.

Dynamically building resource inventories from Schematics workspaces

You can dynamically build your resource inventory from the IBM Cloud resources that you provisioned with Schematics workspaces.

Dynamic resource inventories references IBM Cloud resources that you provisioned with Schematics workspaces. To retrieve the IBM Cloud resources from your workspaces, use predefined resource queries. You do not need to keep track of the IP addresses that were assigned to your target resources as Schematics automatically determines the target hosts when you use this inventory in the Schematics action.

Log in to IBM Cloud console.
Click the Menu icon > Platform Automation > Schematics > Ansible.
Click the playbook name.
Click Inventory > Create Inventory.
Enter a name for your inventory, verify your location, and select your Resource group where you want to create an inventory.
Select the Host groups tab.
Click Create host group.
Enter a name for your host group and select the Schematics workspace that provisioned the target hosts that you want to add to your host group.
Optional: Click Add query to add another condition to your query and limit the number of target hosts that are added to your host group. You can choose to identify your hosts by using the resource name or a tag. For more information, see supported resource queries.
Repeat step 5-8 to add more host groups.
From the table list, select the host groups that you want to include in your resource inventory.
Click Create inventory.
Follow the steps to create the Schematics actions and use the resource inventory that you created.

Supported resource queries

Resource query
Supported query	Description
Workspace name	Select all the IBM Cloud resources from a specific workspace.
Workspace name AND resource name	Select a specific resource from a specific workspace by using the resource name. To select multiple resources from the same workspace, you can add multiple queries of this type.
Workspace name AND tag	Select a specific resource from a specific workspace by using tags. Tags are added to the resource when you create the workspace and provision your resource. To select multiple resources with different tags from the same workspace, you can add multiple queries of this type.

Limitations

Review the following limitations of dynamic inventories in Schematics:

You can choose among the supported queries to select the target virtual server instances to include in your resource inventory.
Schematics retrieves the IP address of a target Virtual Servers for VPCs and adds the IP address to the resource inventory. If the target Virtual Servers for VPC has a public IP address, the public IP address is used for the resource inventory. If there is no public IP address, the private IP address is used for the resource inventory.
All target hosts must be configured with the same public SSH key. When you use the static inventory file in your Schematics action, you can specify one SSH key to authenticate with all target hosts that are included in your resource inventory. The SSH key should contain \n at the end of the key details in case of command-line or API calls. For more information about SSH keys, see Adding an SSH key.