Cloud Block Storage Service (CBS)

The other core service provided by EPAM Cloud is a Cloud Block Storage service, that allows performing various manipulations related to storage resources. This includes default system disk provisioning, working with additional storage volumes, disk recovery points, and VM images.

Below, you can find the detailed information on each of these options.

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The current page gives the general information on the service and the main workflows. However, while working with the services, our users encounter new questions they need assistance with. The most frequently asked questions on EPAM Cloud Services are gathered on the Cloud Services FAQ page.
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Related CLI Commands

The table below provides the list of service-related commands and their descriptions:

Command Short Command Description
or2-create-attach-volume or2addattol Creates a new volume and attaches it to the instance
or2-detach-volume or2detvol Detaches the specified volume from its parent instance
or2-attach-volume or2attvol Attaches a detached volume to the specified instance
or2-resize-volume or2resvol Resizes the specified storage volume
or2-describe-volumes or2dvol Describes the existing volumes
or2-delete-volume or2delvol Deletes an existing volume
or2-create-checkpoint or2ccp Creates an instance recovery point
or2-describe-checkpoints or2dcp Describes the checkpoints created for the specified instance
or2-revert-to-checkpoint or2rcp Reverts the instance to the latest available checkpoint
or2-go-to-checkpoint or2gcp Reverts the instance to the specified checkpoint
or2-delete-checkpoint or2delcp Deletes the specified checkpoint
or2-create-image or2cim Creates an image based on the instance and its storages
or2-describe-images or2dim Displays the images available for the project and region
or2-delete-image or2delim Deletes a custom machine image

Further on this page, you can find the examples of the commands usage for storage manipulation.

Default disk storage

When you run a VM in EPAM cloud, the VM automatically includes a system disk, the volume of which depends on the VM's operating system: 40GB for Linux instances, and 100GB - for Windows.

In Azure, the system disk storage has capacity up to 127GB.

For more details on Azure storages, please see this page.

In AWS, the system storage size depends on the AMI used to run the instance. The details on the the storage concepts in AWS, see the this page.

Additional volumes manipulation

Apart from using the default system volumes, you can also create and attach additional ones. The size of the additional storage volumes is specified by you. All the manipulations are performed by means of Maestro CLI commands:

The or2-create-attach-volume (or2addattvol) command creates and attaches a storage volume (1GB in the example) to the specified instance:

or2addattvol -i instance_id -p project -r region --size 1

The attached volume should be mounted properly on your VM. Please see the Maestro CLI User Guide (Working with Volumes section) for the details on this process.

In AWS, you can detach an additional volume from its instance using the or2-detach-volume (or2detvol) command. The command can be run only for stopped instances:

or2detvol -p project -r region -v volume_id

The attach a detached volume in an AWS region to a new instance, use the or2-attach-volume (or2attvol) command:

or2attvol -d system_device -i instance_id -v volume_id -p project -r aws_region

You can also use the or2-resize-volume (or2resvol) command to change the size of your volume, if the VM is located in AWS or EPAM regions:

or2resvol -p project -r region -v volume_id -s new_size_in_gb

To find information about the volumes existing in your project/region, or on a specific VM, use the or2-describe-volumes (or2dvol) command:

or2dvol -p project -r region -i [instance_id]

To delete an existing volume, use the or2-delete-volume (or2delvol) command:

or2delvol -p project -r region -v volume_id

Please note that due to EPAM Cloud infrastructure specifics, there are some daily resource creation quotas applied to each project. These quotas regulate the number of storage volumes that can be created in one project/EPAM-region, and their size:

Item Description Daily Limit
Volumes Number of storage volumes created 5
Volume Size Size of each storage volume 500GB
Total storage Total size of all volumes 2.5TB

Disk Recovery Points

EPAM Cloud allows to create checkpoints. Checkpoints are instance recovery points, containing the data (storage, memory, other devices) of an instance, including storage volumes at the specific point in time.

The checkpoints are to be created on the stopped instances.

To create a new checkpoint, stop the VM and run the or2-create-checkpoint (or2ccp) command:

or2ccp -p project -r region -i instance_id -d checkpoint_description

To get information on the checkpoints on a specified instance, use the or2-describe-checkpoints (or2dcp) command:

or2dcp -p project -r region -i instance

To revert an instance to the latest available checkpoint, use the or2-revert-to-checkpoint (or2rcp) command:

or2rcp -p project -r region -i instance_id

To revert an instance to the specified checkpoint, use the or2-go-to-checkpoint (or2gcp) command:

or2gcp -p project -r region -i instance_id -c checkpoint_id

To delete an existing checkpoint, stop the VM and run the or2-delete-checkpoint (or2delcp) command:

or2delcp -p project -r region -i instance_id -c checkpoint_id

Deleting a checkpoint can take long time, even several hours. The parent VM is unavailable till the deletion process is completed.

Please note that there is a number of limitations and recommendations on checkpoint usage in Cloud. The main of them are:

- We recommend making checkpoints immediately before you introduce critical changes to an instance, and deleting/reverting to the checkpoint as soon as you have verified proper working state of the instance.

- Checkpoints are not designed to be used as direct backups. A snapshot file is basically a change log of the original disk volume. It combines with the original disk files to make up the current state of the virtual machine. If the base disks are deleted or corrupt, the snapshot files are useless.

- Creation and management of instance checkpoint is not supported in AWS and Azure-type regions.

- All storage-related commands (or2attvol, or2addattvol, or2delvol, or2detvol) for the instance are disabled once a checkpoint has been created.

VM Images Creation

EPAM Orchestrator allows to create images from the existing instances. This allows to save the existing settings and data and to create the necessary number of copies.

However, before creating an image, it is necessary to prepare the instance properly, to avoid further issues with running new VM. Please see the Cloud Services (VM Images Service) for the details on this process.

Currently, images creation is unavailable in EPAM-KZ1 and Azure regions.

After all the preparations are done, make sure the VM is stopped (use or2stop command if needed) and run the or2-create-image (or2cim) command to create an image of the target VM:

or2cim -p project -r region -i instance_id -n image_name -d image_description

The image is created for project/region. After the creation is finished, you can find it in the list of the images returned by the or2-describe-images (or2dim) command. Custom images will have the "project" type:

or2dim -p project -r region

To remove a custom image, use the or2-delete-image (or2delim) command:

or2delim -p project -r region -i image_name -y

References

More detailed information on volume, checkpoint and image manipulations can be found in the corresponding sections of the EPAM Cloud Services Guide. For detailed description of Maestro CLI commands used to work with volumes, checkpoints and images, please refer to the Maestro CLI User Guide