Instances (VMs)

In a Nutshell

Instances can be created via the Dashboard wizard, select: name → image → flavor → network → SSH key → launch. If your project runs out of resources, you can request additional quota via the bwSupportPortal. Existing instances can be resized to larger flavors. Always back up important data beforehand, as the VM will reboot during the process. To access your bwCloud-OS virtual machines, you must register an SSH key pair and assign it when creating instances.

Creating Instances

Create an Instance (GUI)

1. Click Instances in the left menu. On the new page, select the Launch Instance button. A dialog will open, guiding you through the process step by step.
2. First, give the instance a meaningful name (e.g., myVM01). Click Next at the bottom.
3. Select a source/image for the instance (e.g., Debian X). Add the selection using the ↑ symbol; the chosen image will appear under Allocated. To discard a selection, click the ↓ symbol in the row.
4. In the next step, select a Flavor. If the current quota is too low, a yellow warning icon will appear.
5. Next, choose the Network. In most cases, the default settings are usually sufficient; no changes are needed.
6. For the Security Group, no adjustments are necessary. Changes can be made later if needed.
7. Select the public SSH key to be integrated into the instance. This step is mandatory; without a registered SSH key, access to the running instance is not possible.
8. Click Launch Instance. The instance will start.
9. After the instance has successfully started, the IP address will be displayed in the overview. The instance can be accessed at this address.

Configure an Instance with Ansible

It is also possible to create an instance automatically. Details can be found here.

Resources of Instances

Various resource packages (flavors) are available in bwCloud-OS. If you need more quota to use them, you can request it, as explained here. BwCloud-OS Provided-Flavors

Resizing of an instance

If your project has been allocated enough quota (vCPU, RAM, etc.), you can upgrade an existing VM to a larger flavor. This will restart the VM and change the flavor (vCPU/RAM).

Important:

• Data on attached volumes (Cinder) will remain unchanged.
• Back up important data before performing the resize.

Prerequisites

• Sufficient quota in the selected region.
• Appropriate larger flavor available (see Hardware Flavors).
• Schedule a maintenance window (short restart / brief downtime).

Step-by-Step (Dashboard)

1. Log in to the bwCloud-OS Dashboard and select the desired region in the top left.
2. Navigate to Project → Compute → Instances.
3. Open the dropdown menu for the desired instance and select Resize Instance.
4. Select a larger flavor (e.g., from m1.small to m1.medium) and confirm with Resize.
5. Wait until the status shows VERIFY_RESIZE and the VM is reachable again.

After Resizing: Verify & Confirm

1. Check that the resources match:
   1. RAM/CPU: free -h, nproc
   2. Disk layout: lsblk, df -h
2. If everything is working: select Confirm Resize in the instance dropdown.
3. If problems occur: select Revert Resize (restores the previous flavor).

Notes

• The VM will be restarted during the resize; the IP address remains unchanged.
• You can resize an instance to a smaller flavor to reduce allocated resources. However, this is not recommended, as it may lead to unpredictable behavior or system instability.
• Attached data volumes must be resized separately via Volumes → Extend Volume and then extended within the guest system (e.g., sudo resize2fs or sudo xfs_growfs).

Connecting to Instances

SSH Keys

To connect to your virtual machines, you need an SSH key pair. You can either use your own keys or generate new ones via bwCloud-OS. Detailed instructions can be found here.

SSH ACCESS

After your instance is running, you can connect via SSH from Windows, macOS, or Linux using the following command:

ssh -i /path/to/private-key <username>@<ip-address>

The corresponding SSH usernames are listed in this reference list.

LOST ACCESS

If you lose your SSH key, it cannot be replaced — not even by the Support. Access is only possible if you previously enabled password login via the virtual console.

A (tedious) workaround is described here.