This document covers the most frequently asked questions for the EOSC EU Node Virtual Machines service.
Which site am I connected to?
Look in the address bar in your browser when connected to the OpenStack dashboard after doing a reservation in the EOSC portal and then clicking "View Externally". Look up the URL in URL bar and consult the table below.
| URL | Site operator |
|---|---|
| https://eu-1.iaas.open-science-cloud.ec.europa.eu/ | PSNC |
| https://eu-2.iaas.open-science-cloud.ec.europa.eu/ | Safespring |
The EOSC project is an open architecture designed to allow different backing sites to deliver their services. These services might in some respects differ a bit, but are built on the same principles. These differences can sometimes change the details on how things are done. When creating a reservation in the EOSC portal, the default behaviour is to reserve the resources in a round-robin fashion, either on eu-1 or eu-2. This behaviour can not be changed when doing reservations from the personal Default project, it will always be round robin and you see which site by inspecting the URL bar described above.
If you have the rights to create a Group project, you actually can choose which site you want the reservation to be done in if you check the checkbox "Choose destination site":
I'm having problems connecting to my newly created instance. What could it be?
Check that you do not have more than ONE interface connected to the instance. Connecting more than one network interface to an instance is not recommended. In Safespring the gateway address is provided by default and in PSNC it is possible to configure two networks with different routers that provide the default gateway for the instance with DHCP. Having two interfaces and two default gateways will cause a conflict in the instance which to use and cause asymmetric routing. Therefore it is not recommended.
You should also check that you have created the correct Security Groups and that they are applied to the instance, by picking "Edit Security Groups" in the dropdown meny at the instance row.
I see different kinds of flavors. Which one should I use?
In both Safespring and PSNC there are different kind of flavours with different configuration of CPU, memory and storage. They can mainly be grouped into two different groups: flavours with local ephemeral storage and flavours without. You can see if a flavours comes with local storage or not by viewing the "Root disk" column in the flavour listing. If it says zero, the flavours does not have local storage storage, and if it has a number other than zero it has local storage.
Flavours without ephemeral storage have to be booted from a volume. How to do this is described in the user scenarios.
Flavours with ephemeral storage have to be booted from an image. This is also described in the user scenarios.
The table below shows the different combinations:
| Boot Source = Image | Boot Source = Volume | Boot Source = Image and "Create New Volume" set | |
|---|---|---|---|
| Flavour without ephemeral storage (Root Disk = 0) | Invalid - no place to store the image | Valid . Create the volume beforehand under "Volumes" and populate the volume with an image of your choosing. | Valid - The volume will be automatically created and populated with the chosen image. |
| Flavour with ephemeral storage (Root disk ≠ 0) | Valid - flavour comes with storage which can be used to store the image. | Invalid - booting an instance from a volume which already has storage will render an error | Invalid - booting an instance from a volume which already has storage will render an error |
If you get an quota error that looks something like this when you launch your instance, that means that you have tried to launch a flavor which comes with ephemeral storage and also have attached a volume to it by choosing "Create Volume = Yes". 
This type of flavor (with Root disk ≠ 0) means that you should not create the volume, and instead leave the "Create Volume = no".
I see that eu-1 and eu-2 uses different image formats, RAW and QCOW2. What does that mean?
Yes, it is true that eu-1 uses RAW as the format for the provided images and eu-2 uses QCOW2. Depending on how the provider have set up the backing Ceph storage, using RAW could be beneficial in certain circumstances. This has no practical implication for the user, it is still the operating system denoted by the image name that will be booted.
If the user wants to upload their own images, that is also possible. Both eu-1 and eu-2 supports both RAW and QCOW2 so the user can upload either image format.