fabrikate

Fabrikate

Fabrikate helps make operating Kubernetes clusters with a GitOps workflow more productive. It allows you to write DRY resource definitions and configuration for multiple environments while leveraging the broad Helm chart ecosystem, capture higher level definitions into abstracted and shareable components, and enable a GitOps deployment workflow that both simplifies and makes deployments more auditable.

In particular, Fabrikate simplifies the frontend of the GitOps workflow: it takes a high level description of your deployment, a target environment configuration (eg. qa or prod), and renders the Kubernetes resource manifests for that deployment utilizing templating tools like Helm. It is intended to run as part of a CI/CD pipeline such that with every commit to your Fabrikate deployment definition triggers the generation of Kubernetes resource manifests that an in-cluster GitOps pod like Weaveworks' Flux watches and reconciles with the current set of applied resource manifests in your Kubernetes cluster.

Getting Started

First, install the latest fab cli on your local machine from our releases, unzipping the appropriate binary and placing fab in your path. The fab cli tool, helm, and git are the only tools you need to have installed.

Let's walk through building an example Fabrikate definition to see how it works in practice. First off, let's create a directory for our cluster definition:

$ mkdir mycluster
$ cd mycluster

The first thing I want to do is pull in a common set of observability and service mesh platforms so I can operate this cluster. My organization has settled on a cloud native stack, and Fabrikate makes it easy to leverage reusable stacks of infrastructure like this:

$ fab add cloud-native --source https://github.com/timfpark/fabrikate-cloud-native

Since our directory was empty, this creates a component.yaml file in this directory:

name: mycluster
subcomponents:
- name: cloud-native
  generator: component
  source: https://github.com/timfpark/fabrikate-cloud-native
  method: git
  branch: master

A Fabrikate definition, like this one, always contains a component.yaml file in its root that defines how to generate the Kubernetes resource manifests for its directory tree scope.

The cloud-native component we added is a remote component backed by a git repo fabrikate-cloud-native. Fabrikate definitions use remote definitions like this one to enable multiple deployments to reuse common components (like this cloud-native infrastructure stack) from a centrally updated location.

Looking inside this component at its own root component.yaml definition, you can see that it itself uses a set of remote components:

name: "cloud-native"
generator: "static"
path: "./manifests"
subcomponents:
  - name: "elasticsearch-fluentd-kibana"
    source: "https://github.com/timfpark/fabrikate-elasticsearch-fluentd-kibana"
    method: "git"
  - name: "prometheus-grafana"
    source: "https://github.com/timfpark/fabrikate-prometheus-grafana"
    method: "git"
  - name: "istio"
    source: "https://github.com/evanlouie/fabrikate-istio"
    method: "git"
  - name: "kured"
    source: "https://github.com/timfpark/fabrikate-kured"
    method: "git"
  - name: "jaeger"
    source: "https://github.com/bnookala/fabrikate-jaeger"
    method: "git"

Fabrikate recursively iterates component definitions, so as it processes this lower level component definition, it will in turn iterate the remote component definitions used in its implementation. Being able to mix in remote components like this makes Fabrikate deployments composable and reusable across deployments.

Let's look at the component definition for the elasticsearch-fluentd-kibana component:

{
  "name": "elasticsearch-fluentd-kibana",
  "generator": "static",
  "path": "./manifests",
  "subcomponents": [
    {
      "name": "elasticsearch",
      "generator": "helm",
      "repo": "https://github.com/helm/charts",
      "path": "stable/elasticsearch"
    },
    {
      "name": "elasticsearch-curator",
      "generator": "helm",
      "repo": "https://github.com/helm/charts",
      "path": "stable/elasticsearch-curator"
    },
    {
      "name": "fluentd-elasticsearch",
      "generator": "helm",
      "repo": "https://github.com/helm/charts",
      "path": "stable/fluentd-elasticsearch"
    },
    {
      "name": "kibana",
      "generator": "helm",
      "repo": "https://github.com/helm/charts",
      "path": "stable/kibana"
    }
  ]
}

First, we see that components can be defined in JSON as well as YAML (as you prefer).

Secondly, we see that that this component generates resource definitions. In particular, it will emit a set of static manifests from the path ./manifests, and generate the set of resource manifests specified by the inlined Helm templates definitions as it it iterates your deployment definitions.

With generalized helm charts like the ones used here, its often necessary to provide them with configuration values that vary by environment. This component provides a reasonable set of defaults for its subcomponents in config/common.yaml. Since this component is providing these four logging subsystems together as a "stack", or preconfigured whole, we can provide configuration to higher level parts based on this knowledge:

config:
subcomponents:
  elasticsearch:
    namespace: elasticsearch
    injectNamespace: true
    config:
  elasticsearch-curator:
    config:
      namespace: elasticsearch
      configMaps:
        config_yml: |-
          ---
          client:
            hosts:
              - elasticsearch-client.elasticsearch.svc.cluster.local
            port: 9200
            use_ssl: True
  fluentd-elasticsearch:
    namespace: fluentd
    injectNamespace: true
    config:
      elasticsearch:
        host: "elasticsearch-client.elasticsearch.svc.cluster.local"
  kibana:
    namespace: kibana
    injectNamespace: true
    config:
      files:
        kibana.yml:
          elasticsearch.url: "http://elasticsearch-client.elasticsearch.svc.cluster.local:9200"

This common configuration, which applies to all environments, can be mixed with more specific configuration. For example, let's say that we were deploying this in Azure and wanted to utilize its managed-premium SSD storage class for Elasticsearch, but only in azure deployments. We can build an azure configuration that allows us to do exactly that, and Fabrikate has a convenience function called set that enables to do exactly that:

$ fab set --environment azure --subcomponent cloud-native.elasticsearch data.persistence.storageClass="managed-premium" master.persistence.storageClass="managed-premium"

This creates a file called config/azure.yaml that looks like this:

subcomponents:
  cloud-native:
    subcomponents:
      elasticsearch:
        config:
          data:
            persistence:
              storageClass: managed-premium
          master:
            persistence:
              storageClass: managed-premium

Naturally, an observability stack is just the base infrastructure we need, and our real goal is to deploy a set of microservices. Furthermore, let's assume that we want to be able to split the incoming traffic for these services between canary and stable tiers with Istio so that we can more safely launch new versions of the service.

There is a Fabrikate component for that as well called fabrikate-istio-service that we'll leverage to add this service, so let's do just that:

$ fab add simple-service --source https://github.com/timfpark/fabrikate-istio-service

This component creates these traffic split services using the config applied to it. Let's create a prod config that does this for a prod cluster by creating config/prod.yaml and placing the following in it:

subcomponents:
  simple-service:
    namespace: services
    config:
      gateway: my-ingress.istio-system.svc.cluster.local
      service:
        dns: simple.mycompany.io
        name: simple-service
        port: 80
      configMap:
        PORT: 80
      tiers:
        canary:
          image: "timfpark/simple-service:441"
          replicas: 1
          weight: 10
          port: 80
          resources:
            requests:
              cpu: "250m"
              memory: "256Mi"
            limits:
              cpu: "1000m"
              memory: "512Mi"

        stable:
          image: "timfpark/simple-service:440"
          replicas: 3
          weight: 90
          port: 80
          resources:
            requests:
              cpu: "250m"
              memory: "256Mi"
            limits:
              cpu: "1000m"
              memory: "512Mi"

This defines a service that is exposed on the cluster via a particular gateway and dns name and port. It also defines a traffic split between two backend tiers: canary (10%) and stable (90%). Within these tiers, we also define the number of replicas and the resources they are allowed to use, along with the container that is deployed in them. Finally, it also defines a ConfigMap for the service, which passes along an environmental variable to our app called PORT.

From here we could add definitions for all of our microservices in a similar manner, but in the interest of keeping this short, we'll just do one of the services here.

With this, we have a functionally complete Fabrikate definition for our deployment. Let's now see how we can use Fabrikate to generate resource manifests for it.

First, let's install the remote components and helm charts:

$ fab install

This installs all of the required components and charts locally and we can now generate the manifests for our deployment with:

$ fab generate prod azure

This will iterate through our deployment definition, collect configuration values from azure, prod, and common (in that priority order) and generate manifests as it descends breadth first. You can see the generated manifests in ./generated/prod-azure, which has the same logical directory structure as your deployment definition.

Fabrikate is meant to used as part of a CI / CD pipeline that commits the generated manifests checked into a repo so thatthey can be applied from a pod within the cluster like Flux, but if you have a Kubernetes cluster up and running you can also apply them directly with:

$ cd generated/prod-azure
$ kubectl apply --recursive -f .

This will cause a very large number of containers to spin up (which will take time to start completely as Kubernetes provisions persistent storage and downloads the containers themselves), but after three or four minutes, you should see the full observability stack and Microservices running in your cluster.

Documentation

We have complete details about how to use and contribute to Fabrikate in these documentation items:

• Component Definitions
• Config Definitions
• Contributing

Community

Please join us on Slack for discussion and/or questions.

Bedrock

We maintain a sister project called Bedrock. Bedrock provides automa that makes operationalizing Kubernetes clusters with a GitOps deployment workflow easier, automating a GitOps deployment model leveraging Flux, and provides automation for building a CI/CD pipeline that automatically builds resource manifests from Fabrikate defintions.