Key Concepts
Instance
Instances of Bare Metal Server are deployed directly onto non-virtualized physical servers with an operating system and related software installed exclusively. These instances possess various status values, including operational and workload conditions, allowing users to monitor and perform management tasks accordingly.
Instance type
Bare metal server instances allow direct access to the server's processor and memory, making them ideal for workloads requiring non-virtualized environments or proprietary hypervisors. Unlike standard instances, they fully occupy a physical server, ensuring superior performance and stability.
KakaoCloud offers BMS instance types, including memory optimized and accelerated computing, with more options being continuously added.
The general purpose instance in Bare Metal Server will be supported in the future.
Instance lifecycle
Instances possess various status values, such as operational and processing states, allowing their lifecycle from creation to termination to be monitored through the status values and lifecycle stages. You can manage instances by checking this states. The lifecycle of instances provided by Bare Metal Server is as follows:
Instance lifecycle
Commands/Features
| Feature name (CLI command) | Description | State after execution |
|---|---|---|
Start (start) | Starts the instance | Active |
Stop (stop) | Stops the instance | Stopped |
Terminate (terminate) | The instance is running and in a usable status | Shelved_offloaded |
Hard Reboot (hard reboot) | Hard reboot the instance | Active |
Instance rebuild (rebuild) | Reinstall instance OS image and reset key pair | Active |
Delete (delete) | Completely deletes the instance | - |
Instance state and billing
| State | Description | Billed |
|---|---|---|
Spawning | Creating the instance | No |
Active | Running the instance | Yes |
Stopped | Stopping the instance, but resources are still allocated | Yes |
Rebuild_spawning | Rebuilding the instance | Yes |
Rebooting_hard | Force restart of the instance has begun | Yes |
Rebooting_started_hard | Force restarting the instance | Yes |
Powering-off | Stopping the instance | Yes |
Powering-on | Restarting the stopped instance | Yes |
Error | Instance has encountered an error and is unusable | No |
Deleting | Work in progress to completely delete the instance | No |
Image
Depending on the purposes, you can choose the necessary Operating System (OS) and applications to launch an instance.
In the Bare Metal Server, you are not be able to create or manage images directly; only the default images provided by KakaoCloud are available for use.
Default images available
| Category | Image |
|---|---|
| Linux | Ubuntu 20.04 |
| Ubuntu 20.04 (GPU) | |
| Ubuntu 22.04 | |
| Ubuntu 22.04 (GPU) | |
| CentOS Stream 8 | |
| Rocky Linux 8 | |
| Rocky Linux 9 | |
| Alma Linux 9 |
Key pair
A key pair consist of a pair of keys used for secure communication and authentication with instances or virtual machines. This pair is composed of a public key and a private key.
-
Public key: The public key can be shared with others or systems. Users or clients seeking to connect to an instance use this public key to encrypt data and send it to the instance. The public key facilitates the decryption of encrypted data by others or the instance itself.
-
Private key: The private key is a secret key that pairs with the public key and must be securely protected. Only the user or client who owns the key pair should have access to the private key. The private key is used when connecting to an instance, decrypting data, or logging into the instance.
Network
All Bare Metal Server instances are provided within a Virtual Private Cloud (VPC). You can build a logically separated service environment according to the required network requirements. For more information about the network, please refer to VPC.
IAM-based role management
Role management in Bare Metal Server follows IAM role-based access control (RBAC), and all resources within the product are created and managed under a project. Users with Project Admin or Project Member privileges can create and manage all resources under the project. However, only the owner who created the key pair can delete it.
| Permissions by Role | Project Admin | Project Member | Project Reader |
|---|---|---|---|
| Manage project members | ✓ | ||
| Associate public IP | ✓ | ||
| Manage instances | ✓ | ✓ | △(View only) |
| Volumes | ✓ | ✓ | △(View only) |
| Images | ✓ | ✓ | △(View only) |
| Key pair | ✓ | ✓ | △(View only) |