infrakit

InfraKit

InfraKit is a toolkit for creating and managing declarative, self-healing infrastructure. It breaks infrastructure automation down into simple, pluggable components. These components work together to actively ensure the infrastructure state matches the user's specifications. Although InfraKit emphasizes primitives for building self-healing infrastructure, it also can be used passively like conventional tools.

To get started, try the tutorial.

Who InfraKit is for

InfraKit is designed to support setup and management of base infrastructure. For example, it can help you manage a system like a cluster or container orchestrator, ideally relieving you of building custom release and maintenance tools. As a result, it is a low-level tool intended to be used by infrastructure operators directly or indirectly (as a toolkit) through a higher-level tool. Since InfraKit is pluggable, it allows you to manage resources in diverse environments while using shared components and consistent interfaces.

Plugins

InfraKit makes extensive use of Plugins to manage arbitrary systems in diverse environments, which can be composed to meet different needs.

See the plugins documentation for more details.

Building

Your Environment

Make sure you check out the project following a convention for building Go projects. For example,

# Install Go - https://golang.org/dl/
# Assuming your go compiler is in /usr/local/go
export PATH=/usr/local/go/bin:$PATH

# Your dev environment
mkdir -p ~/go
export GOPATH=!$
export PATH=$GOPATH/bin:$PATH

mkdir -p ~/go/src/github.com/docker
cd !$
git clone git@github.com:docker/infrakit.git
cd infrakit

We recommended go version 1.7.1 or greater for all platforms.

Also install a few build tools:

make get-tools

Running tests

$ make ci

Binaries

$ make binaries

Executables will be placed in the ./build directory. This will produce binaries for tools and several reference Plugin implementations:

• infrakit: a command line interface to interact with plugins
• infrakit-group-default: the default Group plugin
• infrakit-instance-file: an Instance plugin using dummy files to represent instances
• infrakit-instance-terraform: an Instance plugin integrating Terraform
• infrakit-instance-vagrant: an Instance plugin using Vagrant
• infrakit-flavor-vanilla: a Flavor plugin for plain vanilla set up with user data and labels
• infrakit-flavor-zookeeper: a Flavor plugin for Apache ZooKeeper ensemble members
• infrakit-flavor-swarm: a Flavor plugin for Docker in Swarm mode.

All provided binaries have a help sub-command to get usage and a version sub-command to identify the build revision.

Design

Configuration

InfraKit uses JSON for configuration because it is composable and a widely accepted format for many infrastructure SDKs and tools. Since the system is highly component-driven, our JSON format follows simple patterns to support the composition of components.

A common pattern for a JSON object looks like this:

{
   "SomeKey": "ValueForTheKey",
   "Properties": {
   }
}

There is only one Properties field in this JSON and its value is a JSON object. The opaque JSON value for Properties is decoded via the Go Spec struct defined within the package of the plugin -- for example -- vanilla.Spec.

The JSON above is a value, but the type of the value belongs outside the structure. For example, the default Group Spec is composed of an Instance plugin, a Flavor plugin, and an Allocation:

{
  "ID": "name-of-the-group",
  "Properties": {
    "Allocation": {
    },
    "Instance": {
      "Plugin": "name-of-the-instance-plugin",
      "Properties": {
      }
    },
    "Flavor": {
      "Plugin": "name-of-the-flavor-plugin",
      "Properties": {
      }
    }
  }
}

The group's Spec has Instance and Flavor fields which are used to indicate the type, and the value of the fields follow the pattern of <some_key> and Properties as shown above.

The Allocation determines how the Group is managed. Allocation has two properties:

• Size: an integer for the number of instances to maintain in the Group
• LogicalIDs: a list of string identifiers, one will be associated with each Instance

Exactly one of these fields must be set, which defines whether the Group is treated as 'cattle' (Size) or 'pets' (LogicalIDs). It is up to the Instance and Flavor plugins to determine how to use LogicalID values.

As an example, if you wanted to manage a Group of NGINX servers, you could write a custom Group plugin for ultimate customization. The most concise configuration looks something like this:

{
  "ID": "nginx",
  "Plugin": "my-nginx-group-plugin",
  "Properties": {
    "port": 8080
  }
}

However, you would likely prefer to use the default Group plugin and implement a Flavor plugin to focus on application-specific behavior. This gives you immediate support for any infrastructure that has an Instance plugin. Your resulting configuration might look something like this:

{
  "ID": "nginx",
  "Plugin": "group",
  "Properties": {
    "Allocation": {
      "Size": 10
    },
    "Instance": {
      "Plugin": "aws",
      "Properties": {
        "region": "us-west-2",
        "ami": "ami-123456"
      }
    },
    "Flavor": {
      "Plugin": "nginx",
      "Properties": {
        "port": 8080
      }
    }
  }
}

Once the configuration is ready, you will tell a Group plugin to

• watch it
• update it
• destroy it

Watching the group as specified in the configuration means that the Group plugin will create the instances if they don't already exist. New instances will be created if for any reason existing instances have disappeared such that the state doesn't match your specifications.

Updating the group tells the Group plugin that your configuration may have changed. It will then determine the changes necessary to ensure the state of the infrastructure matches the new specification.

Docs

Additional documentation can be found here.

Reporting security issues

The maintainers take security seriously. If you discover a security issue, please bring it to their attention right away!

Please DO NOT file a public issue, instead send your report privately to security@docker.com.

Security reports are greatly appreciated and we will publicly thank you for it. We also like to send gifts—if you're into Docker schwag, make sure to let us know. We currently do not offer a paid security bounty program, but are not ruling it out in the future.

Design goals

InfraKit is currently focused on supporting setup and management of base infrastructure, such as a cluster orchestrator. The image below illustrates an architecture we are working towards supporting - a Docker cluster in Swarm mode.

This configuration co-locates InfraKit with Swarm manager nodes and offers high availability of InfraKit itself and Swarm managers (using attached storage). InfraKit is shown managing two groups - managers and workers that will be continuously monitored, and may be modified with rolling updates.

Countless configurations are possible with InfraKit, but we believe achieving support for this configuration will enable a large number of real-world use cases.

Copyright and license

Copyright © 2016 Docker, Inc. All rights reserved. Released under the Apache 2.0 license. See LICENSE for the full license text.