Migrate Virtual Server

OnApp allows hot and cold migration of virtual servers:

  • Hot migration - the migration of virtual servers between compute resources that share common data stores (or data store zones)
  • Cold migration - the migration of virtual servers and disks between compute resources with local storage or across zones

If you need to change the VS migration bandwidth limitation for vdisks migration, this can be done in the on_app.yml file by adding/editing the value in MB/s for the migration_rate_limit: parameter. The default value is 10MB/s.


Hot migration between compute resources

To hot migrate a virtual server:

  1. Go to your Control Panel's Virtual Servers menu.
  2. Click the label of the virtual server you want to migrate.
  3. Click the Tools button and press the Migrate Virtual Server link.
  4. In the window that appears, choose migration type - Hypervisor.
  5. Choose the target compute resource from the drop-down menu.
  6. Move the Cold-migrate when hot-migration fails slider to the right if you want to apply cold migration in case of hot migration failure.
  7. Click the Start Migration button.

After migration, the power status of your virtual server remains the same as before the migration. If you migrate a virtual server that's running, the whole process is almost unnoticeable.

To check if your Windows template supports hot migration, see http://templates.repo.onapp.com/Windows_templates.html

VS and Disks Hot Migration


Prerequisities

There are several prerequisites for the migration:

  • The current and the target compute resources and data stores should be in the same location. Migration between locations is not possible.

  • Networks must be the same across the zones. That means that compute zones should have the same network attached.

  • The bandwidth from compute resource to compute resource should be sufficient enough to allow transferring of virtual servers.

  • This feature is suitable for VSs with local storage. Be aware, that migration will take much more time if you want to perform it between shared data stores.
  • Be aware, that disk migration is better than full VS migration in case you want to migrate the disks within the same compute zone and if the advanced backup scheme is used. Such scenario is applicable only for the shared data stores within the same compute zone.

  • The hot migration will work only when the VS is running on CentOs 7 KVM compute resources, and they can be migrated only to CentOs 7 KVM compute resources.
  • The hot migration option appears only if the VS is online and your Quick Emulator (QEMU) version is later than 2.6

To hot migrate a virtual server:

  1. Go to your Control Panel's Virtual Servers menu.
  2. Click the label of the virtual server you want to migrate.
  3. Click the Tools button and click the Migrate Virtual Server link.
  4. In the window that appears, choose migration type - Compute Resource and Storage (Hot).
  5. Choose the target compute zone and compute resource from the drop-down menu. The list will include the other zones that you have access to within the same network (i.e. KVM to KVM migration but not KVM to XEN migration). 
  6. Also, you can see each disk associated with the virtual server with a drop-down menu. Choose the data stores where you wish to move each disk. The list will include available data stores associated with the compute zone and compute resource, selected in the previous step.
  7. Move the Are you sure you want to migrate? slider to the right to confirm the hot migration. 
  8. Click the Start Migration button.

  • Hot migration is not performed if VS has temporary disks (attached to or from other VS).

  • Hot migration is not performed for Integrated Storage data stores if any of the disks has snapshots.

  • Hot migration is not applicable for federated VSs, which are built in compute zones submitted to the Marketplace.

  • If you have local backups on the source compute resource, please move them manually to a target compute resource or backup server.

  • If you change the compute resource or data store zone, the billing will be changed according to the prices set for that new zone in the bucket.

  • Go to Control Panel's Settings menu > ConfigurationDefaults tab > Migration options if you want to set migration rate limit and limit of transactions which can be run simultaneously on the target compute resource when migrating a VS.
  • The following disk migration scenarios are applicable: from LVM data store to LVM data store; from LVM data store to Integrated Storage data store; from Integrated Storage data store to LVM data store. This feature is not applicable for SolidFire storage.
  • Disks that are migrated from one LVM data store to another, will be renamed in the source data store. In case of Integrated Storage, disks will remain with the same name at source data store and will be marked as offline zombie disks. You need to delete them manually, otherwise, you will get an error during backward migration.


Cold migration for VSs and disks

There are several prerequisites for the migration:

    • The virtual server should be shut down to perform migration.
    • The current and the target compute resources and data stores should be in the same location. Migration between locations is not possible.

    • Networks must be the same across the zones. That means that compute zones should have the same network attached.

    • The bandwidth from compute resource to compute resource should be sufficient enough to allow transferring of virtual servers.

    • This feature is suitable for VSs with local storage. Be aware, that migration will take much more time, if you want to perform it between shared data stores.
    • Be aware, that disk migration is better than full VS migration in case you want to migrate the disks within the same compute zone and if the advanced backup scheme is used. Such scenario is applicable only for the shared data stores within the same compute zone.


To cold migrate a virtual server:

  1. Go to your Control Panel's Virtual Servers menu.
  2. Click the label of the virtual server you want to migrate.
  3. Click the Tools button and press the Migrate Virtual Server link.
  4. In the window that appears, choose migration type - Hypervisor and Storage (Cold only).
  5. Choose the target compute zone and compute resource from the drop-down menu. The list will include the other zones that you have access to within the same network (i.e. KVM to KVM migration but not KVM to XEN migration). 
  6. Also, you can see each disk associated to the virtual server with a drop-down menu. Choose target data stores for each disk from the drop-down menu. The list will include available data stores associated with the compute zone and compute resource, selected in the previous step.
  7. Click the Start Migration button.
  • Cold migration is not applicable for federated VSs, which are built on compute zones submitted to the Marketplace.

  • If you have local backups on source compute resource, please move them manually to a target compute resource or backup server.

  • If you change the compute resource or data store zone, the billing will be changed according to the prices set for that new zone in the bucket.

  • Go to Control Panel's Settings menu > Configuration > Defaults tab > Migration options if you want to set migration rate limit and limit of transactions which can be run simultaneously on the target compute resource when migrating a VS.
  • The following disk migration scenarios are applicable: from LVM data store to LVM data store; from LVM data store to Integrated Storage data store; from Integrated Storage data store to LVM data store. This feature is not applicable for SolidFire storage.
  • Disks, migrated from one LVM data store to another, will be renamed at source data store. In case of Integrated Storage, disks will remain with the same name at source data store and will be marked as offline zombie disks. You need to delete them manually, otherwise, you will get an error during backward migration.