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| releasenotes.rst | ||
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Introduction
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What is Smaug?
Smaug 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.
It is named after the famous dragon from J.R.R. Tolkien's The "Hobbit", which was known to hoard and guard the treasures of the people.
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 Smaug:
- 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 Smaug 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 Smaug 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 Smaug, 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 Smaug 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
Protectabes are any class or type of entity that can be protected by Smaug. Since setups might have different entities they would like to protect Smaug 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 Smaug 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:
Smaug API Service
These top-level north-bound APIs expose Application Data Protection services to the Smaug 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 Smaug user to access information about which resource types are protectable (i.e. can be protected by Smaug). 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 Smaug 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 Smaug 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 Smaug user to manage protection Operations:
- Create a checkpoint for a given Protection Plan.
- Delete unneeded checkpoints from the provider.
- Status on a given Operation ID.
Checkpoint API
This API enables the Smaug user to access and manage the 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 Smaug user restore a checkpoint on to a restore target:
- Create restored system from a checkpoint.
Smaug 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 as well so that monitoring the operations is independent from the scheduler.
It will be responsible for executing the automatic operations to specific tasks and tracking them.
Automatic Operation
Automatic operations are the core of the scheduler. They define higher level automatic logic. The simple case are scheduled operations that perform basic operations at a specific trigger. There will also be available complex scheduling policies that will perform multiple north-bound basic APIs.
Trigger Engine
This sub-component of the Schedule Service is responsible for generating triggers to begin the execution of the Plan Orchestration.
It can be done based on a Timer or an Event Collector - Open to implementation.
In the first version of Smaug reference implementation, it will only provide time-based triggering.
Scheduled Operation
The sub-component of the Schedule Service is responsible for holding the mapping between a Trigger and Operation(s).
Smaug 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
- Smaug Launchpad Link: https://launchpad.net/smaug
- Smaug Code Review: https://review.openstack.org/#/q/smaug+status:open,n,z
- Smaug Code Repository: https://github.com/openstack/smaug
- Smaug daily IRC Channel: #openstack-smaug
- Smaug 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/smaug
- Smaug Trello Board: https://trello.com/b/Sudr4fKT/smaug