For convenience you can save a certain instance configuration as a template, if it’s frequently used. Template is a list of volumes that attach to instance during it’s launching (Block Device Mapping). The list may contain both empty volumes and volumes created from a snapshot. These volumes may exceed the master image in size.
The table below lists all possible options.
The devices listed above must meet the following requirements:
- there must be root device, CD-ROM or floppy disk;
- root device can’t be empty.
The first volume will be automatically specified as the system volume, while other volumes will be additional ones.
If the snapshot contains OS boot image, then you have to ensure quality and security of instances created from this snapshot before allowing other users to access it. It is strongly recommended to avoid distributing snapshots with a preset system administrator password. A random password can be generated at the system launch and displayed to user via remote console. Be careful when using licensed software. License cloning is not allowed in some cases.
A new instance can be launched immediately after the template is created.
Creating a template¶
There are two ways of creating a template:
- by listing all necessary volumes manually;
- by creating a template of existing instance. In this case, instance must be stopped first.
When creating a template from a VM, images will be created for all the volumes attached to the VM except for CD-ROM and floppy. To avoid inclusion of additional volumes in the template, detach them before the template creation.
When creating your own template, pay attention to the following:
- the system must support ACPI to ensure correct instance stop;
- the system must support obtaining IP address via DHCP, otherwise the instance will be inaccessible from an external network (even if public IP address is associated explicitly);
- the system must have VirtIO drivers installed, otherwise attachment/detachment of additional volumes will be impossible;
- make sure that all services required for remote access to the system are launched when the system starts.
When creating a template, it gets a unique ID in cmi-xxxxxxxx form. We recommend you to give each template a brief description for convenience. It is desirable to specify the OS name and version. To create new template, open Templates section in main menu and click in the working area.
In a dialog window that opens, set new template parameters and select volumes. (Optimization can be disabled when creating a template)
Adding a volume¶
When adding a volume, you can create an empty volume or add a volume from a snapshot prepared earlier. When adding a volume, specify its size and type.
You can add up to 16 volumes to a template, but only the first volume in the sequence will be marked as root device. Use arrow buttons to arrange volumes in list in a desired order.
After the template is created, you can edit its description. Click in the dialog window to apply the changes.
Accessing template from other projects¶
By default, a created template is private. Instance can be launched based on this template only within the project, in which this template was created. You can specify the projects, which should have access to the template, or mark the template as public.
If you select Grant access to other project from the drop-down list, a dialog window is displayed. In this dialog window, enter full name of the project in <project name>@<customer name> format and confirm the action.
If you select Revoke access from other project from the drop-down list, you need to select a project, to which this operation will apply.
The Share template option allows you to share this template with all CROC Cloud users.
For templates, shared with all CROC Cloud users, the Private template option becomes available. This option revokes shared access to the template, making it accessible only within the current project.
Deleting a template¶
Click Delete to delete the selected template. In the dialog window you will also be prompted to delete all snapshots which are associated with this template.
Displaying template properties¶
Click a link with unique ID to display detailed template information.