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Custom Image Templates

Important

As a user you are fully responsible for maintaining and keeping your custom images up to date.

Custom Image Templates in OpenStack provide a way to create pre-configured images that can be used to quickly launch new instances with predefined configurations. These templates streamline the deployment process, ensuring consistency and saving time. Custom images can include the operating system, application software, and other configurations tailored to specific needs.

Why Use Custom Image Templates?

  • Consistency: Deploying instances with a uniform configuration.
  • Efficiency: Reducing the time needed to configure instances.
  • Scalability: Simplifying the process of scaling out applications.

Supported Formats

OpenStack supports various image formats, but RAW and QCOW2 are preferable due to their flexibility and efficiency:

  • RAW: Uncompressed and straightforward, suitable for simplicity and speed.
  • QCOW2: Offers advanced features like compression and snapshots, making it more versatile.

Create Custom Image Templates

Creating custom image templates involves setting up a base image, installing necessary software, and configuring the system.

Navigate to Project > Compute > Images and click Create Image.

Fill in the Create Image form:

  • Name: Enter a descriptive name for the image.
  • Image Description: enter an image description (e.g. my-web-server)
  • Image Source: Upload the image file (RAW or QCOW2 format).
  • Format: Select the format of the image (RAW or QCOW2).
  • Architecture: Specify the architecture (e.g., x86_64).
  • Minimum Disk: Set the minimum disk space required.
  • Minimum RAM: Set the minimum RAM required.
  • Kernel: Choose an image to be used as the kernel (if applicable).
  • Ramdisk: Choose an image to be used as the ramdisk (if applicable).
  • Visibility: Set the visibility of the image:
    • Private: Only accessible by the user who created it.
    • Shared: Can be shared with other users.
    • Community: Available to all users in the community.
  • Protected: Decide if the image should be protected from deletion.

Click Create Image to upload and register the image.

Use the following command to create an image:

openstack image create "MyCustomImage" \
  --file /path/to/image-file.qcow2 \
  --disk-format qcow2 \
  --container-format bare \
  --visibility public \
  --min-disk 10 \
  --min-ram 2048 \
  --property kernel_id=KERNEL_ID \
  --property ramdisk_id=RAMDISK_ID

Explanation:

  • MyCustomImage: The name of your image.
  • /path/to/image-file.qcow2: The path to the image file.
  • qcow2: The disk format (can be raw for RAW format).
  • bare: The container format.
  • --visibility: Set the visibility of the image (options: private, shared, community).
  • --min-disk: Minimum disk size.
  • --min-ram: Minimum RAM size.
  • --property kernel_id=KERNEL_ID: The ID of the kernel image (if applicable).
  • --property ramdisk_id=RAMDISK_ID: The ID of the ramdisk image (if applicable).

Manage Custom Image Templates

Once created, you can manage your custom images through the Horizon or OpenStack CLI.

Navigate to Project > Compute > Images and select an image. Use the dropdown menu attached to the Launch button to edit or delete the image.

To view all images, use:

openstack image list

To view details of a specific image, use:

openstack image show <image_id>

To update image properties, use:

openstack image set <image_id> --property key=value

To delete an image, use:

openstack image delete <image_id>

Use Cases and Best Practices

Use Cases

  • Development Environments: Quickly deploy environments with necessary tools and configurations.
  • Production Deployments: Ensure consistent application deployment across multiple instances.
  • Testing: Create reproducible test environments.

Best Practices

  • Regular Updates: Keep images updated with the latest patches and software versions.
  • Security: Ensure images are free from vulnerabilities before deployment.
  • Metadata Management: Use metadata to categorize and manage images efficiently.
  • Backup: Maintain backups of critical images to prevent data loss.