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Creating a virtual machine in Pouta


You should familiarize yourself with the security instructions and terms of Pouta accounting before launching your first virtual machine.

This document explains a simple way to launch a virtual machine in the Pouta service. Any CSC user with a computing project can request access to the service as described in [Applying for Pouta access]. To use Pouta, you need to have applied Pouta access for your project first. Please make sure you are familiar with the concepts and security issues first. You might also want to take a look at the webinar.

The web interfaces of the Pouta clouds are available at following addresses:

URL Service name Access  cPouta web interface Accessible on the internet ePouta web interface Accessible only from IPs provided for accessing the management interfaces of ePouta

This OpenStack Horizon based interface allows you do basic cloud computing management operations such as launch a new virtual machine and manage security settings. To use this service, you need a CSC account and a cPouta/ePouta project at CSC.

You can log in to cPouta using several accounts. In addition to your CSC account (CSC username and password), you can also use Haka, VIRTU, and Life Science AAI accounts. The Haka, VIRTU and Life Science AAI accounts will work only if they are linked to your CSC account. Accounts can be linked at My CSC.

You can log in to ePouta only using your CSC account.

Preparatory steps

Before creating a Virtual Machine you must do these 3 steps:

  1. Select the correct CSC project.

  2. Create and setup a SSH key pair.

  3. Setting a security group to control the firewall.

Before starting your first virtual machine in cPouta/ePouta, you must first set up a SSH key pair and modify the security settings so that you will be able to connect to your virtual machine.

Selecting the CSC project

Pouta project selection

You may have more than one CSC project with access to Pouta. You can check this from, where you will be able to see all the projects you have access and which ones have cPouta (or ePouta) activated as a service.

Back in Pouta's interface, make sure that you select the correct project. There are two condiderations here:

  • A project is a sandbox which contains resources like Virtual Machines and networks, and anyone with access to that project will be able to see and administer all these resources. They may not be able to access a Virtual Machine, as this is determinated by the SSH keys configured in the machine, but they will be able to delete, reboot, ... etc.
  • Projects are used to determinate billing. Make sure that the costs will go to the correct billing project.

Setting up SSH keys

To open a connection to your virtual machines in cPouta/ePouta, you first need to prove your identity to the Virtual and for that need SSH keys. This is the default (and more secure) way to access Virtual Machines. You only need to set up your SSH keys once per project.

Import public keys

If you are already familiar with SSH keys, you can use your existing SSH keys to access the virtual machines. In the web interface, go to the Compute > Key Pairs section, and select Import Public Key. You need to name your key, keep in mind you will need to use this name when creating Virtual Machines, so the recomendation is to keep it short and informative of the intended use. Secondly paste your public key, it must be in a single line and be in the form of key-type hash comment, for example a RSA key from

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAAAQQCo9+BpMRYQ/dL3DS2CyJxRF+j6ctbT3/Qp84+KeFhnii7NT7fELilKUSnxS30WAvQCCo2yU1orfgqr41mM70MB

If you have not used SSH keypairs before, you need to create one. The web interface can take care of this for you:

  1. Go to the Compute > Key Pairs section, and select Create Key Pair.

    The Access & Security subpage in the cPouta web interface

    Figure The Access & Security subpage in the cPouta web interface

  2. Give your key a name and click in Create Key Pair. You will get a "keyname.pem" to save. Save it in your home directory. This will be the last time you will be able to download this private key, Pouta does not keep a copy in its servers.

    Create key

    Figure The Create Key Pair dialog

Linux and Mac

In order to install the key you downloaded in the previous step (keyname.pem or keyname.cer), you must run this commands:

For MacOS

If you are using Chrome browser in Mac OS X Monterey, you will get keyname.cer instead of keyname.pem. The following procedure will remain same.

mkdir -p ~/.ssh
chmod 700 .ssh
mv keyname.pem ~/.ssh
chmod 400 ~/.ssh/keyname.pem

400 = Only owner can read

When a file in Unix has 400 permissions, it translates to: r-- --- ---

which means, only the owner can read the file. This is the recommended value for SSH, but in case you need to overwrite the file, you will need to give also write permissions: chmod 600 ~/.ssh/keyname.pem.

Before using the newly created key, you should protect it with a passphrase:

chmod 600 ~/.ssh/keyname.pem
ssh-keygen -p -f .ssh/keyname.pem
chmod 400 ~/.ssh/keyname.pem

Windows (PowerShell)

In Windows environments it is recommended to use PowerShell. The process is very similar

mkdir ~/.ssh
mv yourkey.pem ~/.ssh/

Before using the newly created key, you should protect it with a passphrase:

ssh-keygen.exe -p -f yourkey.pem

Then, still from PowerShell, you can use the ssh command to connect to your machine, in the same way it is done from Linux or Mac.

Windows (Putty)

If your copy of Windows does not have the ssh command installed, it is also possible to use Putty.

This is done by using the puttygen tool to load your private key (.pem) and save it in the (password protected) .ppk format which Putty can use.

  1. Download Putty and puttygen, which are available at

  2. Run puttygen and load the key you downloaded (it should be in the Downloads page).

    Putty Gen

  3. Set a password to the key. This is not compulsory, but advised.

  4. Save the key in ppk format, this is the default Putty format for keys.


Now we can use this new in Putty to connect to a Virtual Machine.

  1. Run putty and load the ssh key. Go to Connection > SSH > Auth > Credentials and under Private key file for authentication, use the Browse... button to select the proper .ppk file.

    Private key file for authentication

  2. Once the key is loaded, you will save the session. Go to the Session section and under Saved Sessions write the name of the new session and click save.

Firewalls and security groups

Security groups are sets of firewall rules which limit access to your machines. A virtual machine can use one or more security groups. These firewall rules are made on the OpenStack layer and you may have additional firewall rules within your virtual machine. In case of connectivity problems, you should make sure both the security group and the virtual machine's internal firewall are correctly configured. The "Default" security group comes with rules that allow internal communication between virtual machines that are members of the security group.

A security group can be edited or created in any moment of the Virtual Machine life-cycle. Any change applied to a security group assigned to a Virtual Machine, will be applied instantly to the Virtual Machine.

Do not edit the default security group

As a good practice, we discourage changing the "Default" security group. We recommend instead that you create specific security groups for specific purposes and name them accordingly. For example create a security group called "SSH-VPN" to allow computers from the VPN to SSH/22 to the machines on that security group.

In order to create a new security group:

  1. Go to Network > Security Groups, and click in Create Security Group, name it and add a description.

  2. Then click in Manage Rules, and in the view that is displayed, click Add Rule.

    Add rule

    There is a lot customization available, but in this case it is recommended to use the SSH rule that only requires one parameter: CIDR. The Classless Inter-Domain Routing or CIDR allows you to specify a subnet ( or an specific IP (

  3. In order to find out your IP you can use services like


Your network situation might more complicated than that. You may be behind a proxy. In that case, consult with your network support.


You can also open ports to all possible IP addresses by using as CIDR, but doing this is a bad security practise.


Please note:

  • Deleting the default egress rules (allow any protocol to and ::/0) in cPouta will cause disruption in the metadata service responsible for SSH key injections. If you want to limit egress traffic, you should at least allow outbound traffic to IP, TCP port 80, for SSH key injections to work.
  • Even though the ePouta virtual machines are only accessible via the customer's network, they also need to have security groups configured for them. Otherwise they can not be accessed.
  • It is possible to add and remove security groups on a running instance. This is done from the instances page.

Server Groups

If you want a policy that allows your instances to run (or not) on the same host, you can set up server groups.

Server Groups


You can only add an instance to a server group at instance creation time. Not afterwards!

After clicking on Create Server Group, a windows will open:

Create Server Group

Give a name to your server group and select a policy. You will have the choice between Affinity, Anti Affinity, Soft Affinity and Soft Anti Affinity.

  • Affinity: Instances within a server group with an affinity policy are scheduled to run on the same host whenever possible. The affinity policy aims to keep instances together on the same physical server, which can be beneficial for applications or services that require low-latency communication between instances.

  • Anti Affinity: Instances within a server group with an anti-affinity policy are scheduled to run on different hosts whenever possible. The anti-affinity policy enhances fault tolerance and availability by spreading instances across multiple physical servers. This helps minimize the impact of hardware failures on a single server.

  • Soft Affinity: Soft affinity is a variation of the affinity policy. In a server group with a soft affinity policy, the scheduler attempts to keep instances on the same host, but it is not a strict requirement. If constraints prevent the co-location of instances on the same host, the scheduler can still place them on different hosts. Soft affinity provides a more flexible approach compared to the strict affinity policy.

  • Soft Anti-Affinity: Soft anti-affinity is a variation of the anti-affinity policy. In a server group with a soft anti-affinity policy, the scheduler attempts to place instances on different hosts, but it is not a strict requirement. If constraints prevent the spread of instances across different hosts, the scheduler can still place them on the same host. Soft anti-affinity provides a more flexible approach compared to the strict anti-affinity policy.

To check if your instances are running on the same (or different) hosts, you can type this command:

openstack server show [INSTANCE_NAME | INSTANCE_ID] | grep HostId


The "soft" variants allow for more flexibility in instance placement.
Affinity or anti-affinity policies may not always be possible due to resource constraints or other scheduling limitations.

Launching a virtual machine

Once the SSH keys and security groups are set, you can launch a new virtual machine using the Pouta web interfaces:


  1. In the main page of the Pouta web interface, open the Compute > Instances view.
  2. Click in Launch Instance on the top right. This opens a launch instance screen where you define the properties of the new virtual machine.

    Launch the instance view

    Figure Launch the instance view

  3. On the Details tab of the launch instance view, first write the Instance Name.

  4. Select the Flavour, which is the "size" of the Virtual Machine that you will create. See Virtual machine flavors and billing unit rates for a complete list and descriptions.

  5. In Instance Count you can specify the number of Virtual Machines to create. If in doubt, leave it to 1.

  6. Instance Boot Source. Select "Boot from image" in the drop down menu.


    In case you want to be more cloud-native, you can select the "Boot from image (creates a new volume)" option. This option creates a new persistent volume for your instance. In the event you accidentally delete your instance or it enters an unrecoverable state, the file system of your instance will be saved in this volume. You can later use this volume to boot up a new instance with the same filesystem state as the previous instance.

    Please note

    The "Boot from image (creates a new volume)" approach creates an additional volume which is billed normally as mentioned on our pricing page.

  7. Image Name, this decides which Linux distribution to use. You can select the image that fits more your use case. The images provided by Pouta by default are regularly maintained up to date.

  8. Under the Access & Security tab, you need to configure two options. First you need to choose the name of the Key Pair you have created in the Preparatory Steps. Secondly you need to select under the Security Groups the security group previously created.

    Launch the instance access view


If you click the "+" button, the window will close unexpectedly and a small window popup will appear:

Error plus button

This is a known bug. Please refer to the previous section on how to create your SSH keys.

  1. The Networking tab, make sure that your own network (your project name) is selected.

    Launch the instance network view

  2. Finally, Advanced Options tab allows you to select a Server Group

You can click Launch to start the Virtual Machine creation.

Post creation step

When a virtual machine is launched, it only gets a private IP (192.168.XXX.XXX). This means that meanwhile the machine can access the internet and other virtual machines in the same project, it can not be accessed from outside the project. To be able to access your virtual machine, you need to attach a public IP address to it.


Associate a floating IP is only available for cPouta instances.

  1. Go to Compute > Instances, you should see your Virtual machine listed.

  2. On the right of your new machine's entry, under Actions, click in the drop down menu, and select Associate Floating IP.

    Floating IP association options

    Figure Floating IP association options

  3. Select an IP address under IP Address. If "No floating IP addresses allocated" show up, click in the plus to allocate a new IP to you project, you will need to add a description.

  4. Under Port to be associated select the virtual machine.

  5. Click in Associate.

Floating IP association dialog

Figure Floating IP association dialog

IP billing

Allocated floating IPs are billed at the rate of 0,2 BU/hr. You can additionally read our blog post for management of floating IPs in a cPouta project.

Now we can go to the Connecting to your virtual machine section and log in to the new Virtual Machine.

Last update: May 7, 2024