8. Known problems and limitations

Instances

  • Instance snapshots sometimes fail. This leaves the instance in the suspended state. To work round this issue we recommend users power off their VM before taking a snapshot.
  • Child instances launched using the snapshot of existing parent instance does not have security group predefined as of parent instance, please select the appropriate security group for child instances before launching them.
  • Resizing inside a flavor family (so within standard.*) is possible except for IO flavors. Resizing between flavor families mostly do not work because of the different storage backends. If you use a volume for the root disk then some resizes between flavor families work. If you use a image for root disk then it's possibly dangerous. Always test resizes with a VM you can spare first. If your virtual machines end up in an "error" state please contact us if this happens.
  • Creating large ephemeral disks for legacy flavors takes a long time. A newly launched (legacy flavor) instance with a large ephemeral disk will stay in the "Spawning" state for some time because of this.
  • Performance: For the full hpc-gen1 node flavour (16 cores) some slowdown has been observed with some codes when using more than 12 cores when compared to taito.csc.fi. Please report any performance regressions compared to taito to cloud-support@csc.fi.
  • Network: It's possible to add the same floating IP to multiple instances using the API. There is no warning or error. The last API call is the one which takes effect.

EC2 tools (euca2ools)

  • EC2 is not supported at this time. EC2 credentials can however be used with the Object Storage.
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