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Snapshots

Danger

Snapshots in ETAIS operate differently from snapshots in other cloud providers e.g. Google Cloud, Azure, AWS.

When you create a snapshot from a virtual machine in ETAIS it creates an image of your virtual machine that you can later use to spin up a new virtual machine from the snapshot. While other cloud providers allow you to revert back to a certain state in time of the snapshot ETAIS does not. This is the peculiarity of OpenStack, a Open Source Cloud Computing Infrastructure to which ETAIS is interfaced to.

Before taking snapshots make sure your Virtual Private Cloud has enough free resources allocated. For a snapshot, you will need additional available Storage (GB) resource in the Virtual Private Cloud. When you want to restore a virtual machine from a snapshot you will need additional Storage resource, additional Cores (vCPU) resource and additional RAM (GB) resource.

For example, lets say your VM uses: 

1 vCPU, 1 GB of RAM and 20 GB of Storage
In order to have snapshot of this 20 GB storage device your Virtual Private Cloud should have allocated: 
1 vCPU, 1 GB of RAM and 40 GB Storage
Now when you want to restore from the snapshot, the overall Virtual Private Cloud resources should be: 
2 vCPU, 2 GB of RAM and 60 GB of Storage
Once you have double checked your virtual machine that is it the way you intend it to be, you can then go and delete the old snapshot and the original virtual machine, and then lower your resources back to the initial: 
1 vCPU, 1 GB of RAM and 20 GB of Storage.
During the restoration of a virtual machine from a snapshot the Storage resource has to be tripled. Every vCPU, every GB of RAM and every GB of Storage has to be allocated in the Virtual Private Cloud. Should you now want another snapshot, make sure the resource allocation in the Virtual Private Cloud is again: 
1 vCPU, 1 GB of RAM and 40 GB Storage.
Conclusion, snapshots in ETAIS are like a awkward and continuous spaghetti:

  • add resources to Virtual Private Cloud
  • create a snapshot from a virtual machine
  • restore a virtual machine from a snapshot
  • delete the snapshot
  • delete the old virtual machine
  • create a new snapshot from the restored virtual machine
  • decrease resources in Virtual Private Cloud
  • repeat

Snapshot requirements:

  • Machine downtime - services inaccessible
  • Extra free Storage resource in the Virtual Private Cloud.
  • When restoring from snapshot there needs to be free vCPU, RAM and additionally extra Storage resource.

Taking a snapshot quick guide

  1. Allocate additional Storage resource (GB) in your Virtual Private Cloud by the amount of the original disk.
  2. Click on your virtual machine name.
  3. From the Navigation bar choose Storage.
  4. From the Storage dropdown choose Snapshots.
  5. Click on the Create +
  6. On the pop-up view give a desired name to the snapshot.
  7. Fill out the other optional fields if necessary - Description, Keep until.
  8. Submit.
  9. Done. When the disk is over 50 GB the snapshot creation will take a few minutes on the backend.

Restore from snapshot quick guide

  1. Allocate enough resources for the new virtual machine you are about to create from the snapshot.
  2. Minimally you will need 1 vCPU, 1 GB of RAM and the matching amount of Storage resource.
  3. In the snapshot view (virtual machine name -> Storage -> Snapshots) choose Actions and Restore
  4. From Flavor drop down choose the desired flavor - it is a good idea to choose the same size flavor as the original.
  5. Security Groups should also be the same as the snapshotted virtual machine to avoid potential problems.
  6. Under Networks make sure to choose Auto-assign floating IP
  7. Submit
  8. Once the virtual machine has spun up, ssh into it and check the machine if it is up to your specifications.
  9. Go back to the original virtual machine Actions -> Show all -> Update floating IPs -> Trash can icon -> Submit
  10. Go to the newly restore virtual machine Actions -> Show all -> Update floating IPs -> Trash can icon -> Submit
  11. Go to the newly restore virtual machine Actions -> Show all -> Update floating IPs -> + Add -> Choose the original IP from the dropdown menu -> Submit
  12. Wait a minute, the original IP will show up behind the new machines name.
  13. Done.