karbor/doc/source

Introduction

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What is Karbor?

Karbor is an OpenStack project that provides a pluggable framework for protecting and restoring Data and Metadata that comprises an OpenStack-deployed application - Application Data Protection as a Service.

Mission Statement

To protect the Data and Metadata that comprises an OpenStack-deployed Application against loss/damage (e.g. backup, replication) by providing a standard framework of APIs and services that allows vendors to provide plugins through a unified interface

Typical Use Case: 3-Tier Cloud App

3-Tier Cloud App Web/App/DB

In order to provide full Protection for this typical use case, we would have to protect many resources, which have some dependency between them. The following diagram demonstrates how this dependency looks, in the form of a tree:

These resources can be divided into groups, each of which will be handled by a different plugin in Karbor:

• Volume
• VM
• Network
• Project
• Images

Main Concepts

Protection Providers

Protection providers are defined by the administrator for each tenant. The encapsulate every aspect of the protection procedure, namely, where to place the backup metadata and the data and how to do it. From the tenants perspective as long as it has access to a provider it should be able to set up replication, back up data, and restore data.

Since there could be many protection providers with varied features and options each protection provider exposes what options it provides for each protectable. This allows the UI to dynamically adapt to each provider and show the user what options are available, what they mean and what values are supported.

This allows us to extend the providers without updates to Karbor and allow provider implementation to easily add specialize options.

Example

Let’s take the OpenStack::Cinder::Volume resource Protect action.

One of the action parameters in the Parameters Schema will be "Consistency Level":

"parameters_schema" : {
      "type": "object",
      "properties": {
          "consistency_level": {
              "title": "Consistency Level",
              "description": "The preferred consistency level",
              "enum": [ "Crash", "OS", "Application" ]
          }
      }
  }

Protection Plans

Protection plan encapsulate all the information about the protection of the project. They define what you want to protect, what protection provider will be used for this plan, and what specialized options will be passed to the provider.

There are two main aspect to protection plan. The first is the continuous aspect. When a plans is started it becomes enabled and continues protection processes are started and monitored (eg. replication). As long as the plan is active Karbor will try and make sure the continuous aspects are active and valid.

The other aspect is point in time protection or, as we call them in Karbor, checkpoints. Checkpoints are saved in the protection provider paired with the plan and, as stated, represent a restorable point in time for the plan. When a checkpoint is created Karbor will store in the protection provider all the information required to successfully restore the project covered by the plan to how it was at that specific point in time.

Automatic Operation

Automatic operations are process that the user want to perform without manual intervention. Up until now we described how to manually manage plans and checkpoints. The user can start and suspend plans and create and delete backups manually whenever it wants. This is perfect for small scale deployments but most administrators will want to have these operations automated. As an example they would like to set up checkpoints every day or disable replication over the weekend when the system is not in use.

Automatic operations are varied and their features vary by operation type. There are simple operation like "back up plan" which creates a single checkpoints at the user requested time or even. And there are more complex automatic operations like the RetentionPlan which allows the user to define a complex retention plan to automate the creation and deletion of checkpoints.

Protectables

Protectables are any class or type of entity that can be protected by Karbor. Since setups might have different entities they would like to protect Karbor doesn't bind the API to specific entity types. The admin can even add new protectables during set up as long as the protection provider can handle those entities. This flexibility means that Karbor is agnostic to the relationship between the resources being backed up.

High Level Architecture

The system is built from independent services and a scalable Workflow engine that ties them together:

Karbor API Service

These top-level north-bound APIs expose Application Data Protection services to the Karbor user.

The purpose of the services is to maximize flexibility and accommodate for (hopefully) any kind of protection for any type of resource, whether it is a basic OpenStack resource (such as a VM, Volume, Image, etc.) or some ancillary resource within an application system that is not managed in OpenStack (such as a hardware device, an external database, etc.).

Resource (Protectable) API

Enables the Karbor user to access information about which resource types are protectable (i.e. can be protected by Karbor). In addition, enables the user to get additional information on each resource type, such as a list of actual instances and their dependencies.

Provider API

Enables the Karbor user to list available providers and get parameters and result schema super-set for all plugins of a specific Provider.

Plan API

This API enables the Karbor user to access the protection Plan registry and do the following operations:

• Plan CRUD.
• List Plans.
• Starting and suspending of plans.

Automatic Operation API

This API enables the Karbor user to manage protection Operations:

• Create a checkpoint for a given Protection Plan.
• Delete unneeded checkpoints from the provider.
• Query the status on a given Operation ID.

Checkpoint API

This API enables the Karbor user to access and manage checkpoints stored in the protection provider:

• List all checkpoints given a Bank ID.
• Show Information on a given checkpoint ID.
• Delete a checkpoint.
• Create a checkpoint.

Restore API

This API enables the Karbor user to restore a checkpoint onto a restore target:

• Create restored system from a checkpoint.

Karbor Schedule Service

This subsystem is responsible for scheduling and orchestrating the execution of Protection Plans.

The implementation can be replaced by any other external solution since it uses only functions that are available through the north-bound API.

Once an entity is created, it can be tracked through the north-bound API, so monitoring the operations is independent from the scheduler.

It will be responsible for the automatic execution of specific operations and tracking them.

Automatic Operation

Automatic operations are the core of the scheduler. They define higher level automatic logic. A simple scenario is a set of scheduled operations that perform basic APIs at a specific trigger. There will also be complex scheduling policies available that perform multiple north-bound basic APIs.

Trigger Engine

This sub-component of the schedule service is responsible for generating triggers, which begin the execution of the Plan Orchestration.

It can be done based on a timer or an event collector, based on implementation.

In the first Karbor reference implementation, the trigger engine will only provide time-based triggers.

Scheduled Operation

This sub-component of the schedule service is responsible for holding the mapping between a trigger and operation(s).

Karbor Protection Service

This subsystem is responsible for handling the following tasks:

• Operation Execution
• Protection Provider management

WorkFlow Engine

This pluggable component is responsible for executing and orchestrating the flow of the plan across all protection providers.

Communication and Meetings

• Karbor Launchpad Link: https://launchpad.net/karbor
• Karbor Code Review: https://review.openstack.org/#/q/karbor+status:open,n,z
• Karbor Code Repository: https://github.com/openstack/karbor
• Karbor daily IRC Channel: #openstack-karbor
• Karbor weekly IRC Meeting on even Tuesday at 1500 UTC and on odd Tuesday at 0900 UTC in #openstack-meeting at freenode: https://wiki.openstack.org/wiki/Meetings/karbor
• Karbor Trello Board: https://trello.com/b/Sudr4fKT/karbor

Additional references

• OpenStack Tokyo Summit 2015 talk
• OpenStack Austin Summit 2016 talk
• Karbor overview slide
• Karbor overview blog