A recent survey of 1,500 IT directors from international companies with more than 250 employees by the software maker SUSE LINUX found that 82 percent of those firms already use OpenStack or plan to. The cloud operating system continues to gain in popularity – as does the Open Telekom Cloud based on the open standard. But just how does OpenStack actually work?
The system has a modular structure. A dashboard enables users to group together various software components and administer them centrally. The basic components have names like Nova, Neutron or Swift, and describe key cloud services such as processing power, storage space and networking.
HEAT module as a cloud orchestration tool
The component used to piece together various IT resources is called HEAT. Users can operate this service manually or they can set up their IT resources for machine automation. It can call up virtual machines (VMs) and applications, manage them and deactivate them. To do this, HEAT uses predefined text files, or so-called templates.
These templates can be used to determine which IT resources with specific properties are called up for a customer’s cloud. If the same exact resources are ever needed again, the customer can simply activate the template – saving lots of time and effort.
Understanding HEAT: Common terms
Template: Describes the features of a virtual machine (VM), defines the components it contains, as well as the relationship between components.
Resource: Is the specific object created by HEAT, for example, a VM or a designated storage space.
Stack: Is a group of connected resources that are called up by a template and can be managed by relevant HEAT commands.
The easy way to dial up the HEAT
“HEAT uses templates to define how the IT infrastructure should look like,” says Open Telekom Cloud expert Daniela Ebert. “You have a command line…which then tells the HEAT engine what to do. And the HEAT engine is, let’s say, doing all the work. And at the end you will have resources like VMs as an output, you will have networks like IP addresses, like software deployments.”
A template always has the same structure:
- Template version: There are new versions for templates with each release of OpenStack. So users should ensure they have the current version number. Otherwise they could be using an older version – lacking total functionality.
- Description: This is optional item informing users what the template does.
- Parameters: Users can define all necessary characteristics, such as security or the applicable network.
- Resources: A central element defining which IT resources will be created.
- Outputs: Here the user defines the wished result
The VM used in the screenshots is called “my_instance” and is an OS Nova server. Its features can be found under “properties” – for example, the wanted Open Telekom Cloud flavor or the name of the networked used. The result is a VM with an IP address to the login. Once the template is created, it can be copied at any time to be used again. This means users spend less time making new VMs with the same properties.
At the OpenStack Summit 2017 in Boston, Daniela Ebert from T-Systems explained how to work with HEAT step by step:
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