Instances¶

An instance is a virtual machine (VM) that runs inside ScienceCloud.

When you start a new instance it is never automatically deleted, so we kindly ask you to terminate the instance whenever it's not needed anymore in order to free up resources from the system.

Instance creation and setup¶

To start an instance, you have to choose:

• a VM name
• an image
• a flavor
• (optional) a key pair (if you have only one it will be preselected by the system)
• (optional) a network

We define quotas on a per-project basis, and you check whether you are under quota on the web interface when you try to start a new instance. However, being within your quota does not guarantee access, as it might be possible that during peak periods ScienceCloud will not have enough resources to start your instance even though you are well under your quota.

Launch / Create instance¶

For detailed instructions, please refer to the Training Handout section training / Launch an instance.

Instance launch error: unavailable flavor¶

If your instance enters an "error" state during launch - such as with the message "No valid host was found" - it may be due to the selected flavor being unavailable in ScienceCloud. Please consult the near-real-time ScienceCloud Flavor Availability Report (internal network or VPN required). If the flavor is unavailable, delete the failed instance and retry with an available flavor. For persistent issues, contact us.

Create Windows VMs¶

For detailed instructions, please refer to the article How to create Windows VMs.

Generate SSH keys¶

Like most Infrastructure-as-a-Service (IaaS) platforms, ScienceCloud users are required to upload own SSH public key. This key is injected into instances at launch, enabling secure access via SSH.

When creating an instance, you must select a key pair - either by uploading an existing SSH public key or generating a new one. Only the matching private key, stored securely on your local machine, can be used to access the instance.

SSH keys offer stronger security than passwords and are highly resistant to brute-force attacks. Each key pair consists of a public key (stored on the instance) and a private key (kept on your computer). It is essential to never share your private key.

Instructions for creating and uploading a key pair to ScienceCloud are provided below.

Generate a key pair on Linux/Mac/Windows10¶

For detailed instructions, please refer to the Training Handout section training / create a key on linux mac windows10.

Generate a key pair on older Windows¶

For detailed instructions, please refer to the Training Handout section training / create a keypair on older windows.

Access and connectivity¶

Login to instance¶

Login from Linux/Mac/Windows10¶

For detailed instructions, please refer to the Training Handout section training / login / On Linux/Mac/Windows10 run SSH in terminal.

Login from older Windows¶

If you're using a Windows-based system to control and connect to ScienceCloud and its instances, you need to use tools like PuTTY and PuTTYgen to connect to a running Linux-based instance. Instructions for importing a keypair and connecting to an instance are available here.

When using PuTTY to connect via SSH, users may encounter a Connection timed out error - even if the connection previously worked. If the instance has an IP address in the uzh-only network, access must be made via the UZH VPN.

For detailed instructions, please refer to the Training Handout section training / login / On older Windows.

Security groups¶

The table below lists the default security group created for every new project on ScienceCloud.

For detailed instructions on opening specific ports in the VM, please refer to the Training Handout section training / Access specific ports on your VM.

Associate floating IP¶

To associate an available floating IP to a port of your instance, please refer to the user guide How to start a VM with floating IPs.

Instance management¶

Lock instance to protect against accidental deletion¶

You can prevent accidental deletion by locking your instance. To do this from the OpenStack web interface, use the drop-down menu on the right side of your instance's information panel and select Lock Instance. Locking an instance restricts not only deletion but also actions such as rebooting, attaching or detaching volumes, resizing, and changing the instance state.

Resize instance¶

By selecting "Resize Instance", you can update the instance's flavor by choosing a new one. After the operation completes successfully, the resize needs to be confirmed to take effect.

More information can be found in the following articles in ScienceCloud (Legacy) documentation:

• In the user guide section Resize instance;
• In the article How to resize your instance;
• In the FAQ on troubleshooting an issue related to resizing of an instance I resized my instance and now I get a message stating "WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!". What do I do / Is this a problem?;
• In the FAQ on troubleshooting an issue related to resizing of an instance I resized/rebooted my instance but now I cannot find the files stored on attached volume — what should I do?.

Soft reboot vs. hard reboot¶

You can perform a soft or hard reboot on a running instance.

A soft reboot attempts a graceful shutdown and restart by signaling the operating system to reboot cleanly. It is equivalent to pressing Ctrl+Alt+Del on a physical machine or running the command shutdown -r now. However, if the system is unresponsive, a soft reboot may fail.

A hard reboot forcibly powers down the instance, effectively resetting the server’s power. Hard reboots may cause issues such as filesystem corruption and should be used only as a last resort when a soft reboot is unsuccessful.

For more details, refer to the official documentation:

📘 Reboot an Instance - OpenStack documentation

Pause instance and suspend instance¶

We advise against using the following 2 actions:

Pause instance: pauses the instance and saves its state in memory. This option keeps the resources allocated (vCPUs and memory).

Suspend instance: suspends the instance and saves its state to the current hypervisor disk. This option keeps the resources allocated (vCPUs and memory) and can easily fail as the hard drive of most hypervisor is not big enough to store big amounts of data.

Shut off instance¶

This action powers off the instance. While the instance is shut off, it is not running but still incurs costs. To stop charges completely, the instance must be deleted.

Instance lifecycle management¶

Delete instance¶

To avoid data loss, please consider the following:

• Save important data elsewhere (e.g., on your laptop, on an external hard drive, or on a NAS).
• Use a storage volume to store persistent data. A storage volume can be exchanged between instances and data recovered if the instance operating system becomes corrupt.
• Create an instance snapshot before deleting.

Create snapshot¶

Snapshots are a feature that allows users to capture the running instance setup and save it without the need to pause or shutdown it. These snapshots are disk-only snapshots.

To create a snapshot:

1. Click Shutoff instance (recommended)
2. Click Create Snapshot

New snapshot is displayed in the Images.

For further actions with snapshots - such as sharing, downloading, or troubleshooting common issues - refer to the section Snapshots and Images.

Share access to instance¶

For detailed instructions, please refer to the article How to give other people access to an instance.

Customization and configuration¶

Update and upgrade¶

For detailed instructions, please refer to the Training Handout section training / install packages on a Debian/Ubuntu instance.

Set CET/Zurich local time on an instance¶

Most Ubuntu and Debian servers use UTC as default. You can check your system clock by running the date command and checking if UTC is printed.

On Ubuntu or Debian servers, you can change the timezone to Europe/Zurich by running:

sudo dpkg-reconfigure tzdata

A dialog window will appear, allowing you to select your preferred timezone. A system restart is suggested once the local timezone is set.

To verify that the change was successful, re-run the date command.

Custom software installation¶

For guidance on installing or running custom software, see the related articles covering R, MATLAB, Gaussian, Apache Hadoop/Spark with SWIFT, and docker compose.