Quarks - a quickstart guide to deploying BOSH releases on K8s

Aug 25, 2020| Jessica Stenning

Deploying BOSH releases to Kubernetes is entirely possible, but can be a little tricky to figure out from the documentation alone. This blog post fills in the gaps to provide a step-by-step guide for deploying a BOSH release on K8s with Quarks, deploying Redis as an example.

As the Cloud Foundry (CF) community moves towards the Kubernetes era of dominance, a few possible solutions for deploying CF on K8s have surfaced; one such solution is the Quarks/KubeCF combination. KubeCF is a Cloud Foundry Application Runtime (CFAR) distribution for Kubernetes. It is used with Quarks to deploy and manage cf-deployment releases, but beyond just CF, Quarks has introduced a broader method for deploying BOSH releases on K8s: BOSH releases are converted to Docker Images, and the BOSH deployment manifest is converted to a custom Kubernetes boshdeployment resource.

What is Quarks?

When we refer to Quarks we’re largely referring to the deployment of the cf-operator (soon to be renamed the quarks-operator to reflect its broader functionality). The cf-operator brings with it custom resource definitions (CRDs) that extend the Kubernetes API. Once deployed, the cf-operator watches for the creation of the custom boshdeployment resource (more on this later), then works its magic to translate the sum into a desired manifest and ultimately a running BOSH deployment on K8s.

If you’d like to learn more about how Quarks controllers handle the complete workflow from the custom boshdeployment resource, through to the translation and creation of Kubernetes native StatefulSets, Pods etc, I’d recommend taking a look at the docs - the controller diagrams are especially helpful.

Steps for deploying a BOSH release with Quarks

The steps we’ll be exploring in more detail are:

  1. Check if Helm chart would be simpler
  2. Install cf-operator (first time only)
  3. Build Docker image using Fissile
  4. Create ConfigMap YAML containing manifest
  5. Add BPM ops file (if necessary)
  6. Create BOSHDeployment YAML
  7. kubectl apply

Quarks deployment flowchart

The flowchart above illustrates the steps needed to deploy a BOSH release with Quarks, dependent on your use case the sequence of those steps varies. The remainder of this post will take you through each of the possible streams, culminating in a successful kubectl apply.

1. Is there a Helm Chart already?

In any instance, a good starting point is to ask yourself whether a Helm Chart already exists for the BOSH release you want to deploy (as is the case for KubeCF and Concourse CI). If an upstream Helm Chart does exist, it’s likely that will the more straightforward deployment process.

If an upstream Helm Chart doesn’t exist, you’ll need to install the cf-operator.

1.1 Installing cf-operator

This is fairly straightforward and can be completed with Helm. There are a few customisations that can be set by passing additional values to the install command, but broadly you’ll want to make sure the namespace you place the cf-operator in is sensibly named and dedicated. The example below also sets the namespace that the cf-operator will ‘watch’ for the creation of custom resources.

helm repo add quarks https://cloudfoundry-incubator.github.io/quarks-helm/

helm install cf-operator quarks/cf-operator \
  --namespace cf-operator \
  --set "global.singleNamespace.name=mydeployment"

For a full list of customisations that can be passed to the cf-operator installation take a look at the Helm Chart.

2. Do you have a Docker Image?

Do you need to convert your you BOSH release into a Docker Image, or does this exist already? If the answer is ‘yes, I have a Docker Image of my release’, then you can go ahead and skip the rest of this section.

2.1 Converting Releases to Docker Images with Fissile

If you’re still reading, the first step is to convert your BOSH release to a Docker Image; Quarks recommends Fissile for this purpose.

Currently there are no releases published on the Fissile Github page, and while this isn't documented, the latest Fissile builds can be retrieved from this S3 Bucket rather than building Fissile yourself: s3://cf-opensusefs2/fissile/develop/

As a binary, Fissile was originally designed for use with SCF and, as a result, a lot of its functionality isn’t relevant for this use case. The only command that is needed to create a Docker Image is the build images command. A fully constructed version of this command, using the Concourse BOSH release as an example, looks like this:

fissile build release-images --stemcell=splatform/fissile-stemcell-opensuse \
  --name=concourse --version=6.4.1 \
  --sha1=a8f4072712dd6eec11c1f081362535c34166671d \
  --url=https://bosh.io/d/github.com/concourse/concourse-bosh-release?v=6.4.1

When running this command, the stemcell we pass is the splatform/fissile-stemcell-opensuse Fissile stemcell. This will result in a built image with a tag format as follows:

Fissile docker Image

The image can then be tagged and pushed to dockerhub or private registry to be referenced in your deployment.

docker tag concourse:opensuse-42.3-51.g7fef1b7-30.95-7.0.0_374.gb8e8e6af-6.4.1 \
  engineerbetter/concourse:opensuse-42.3-51.g7fef1b7-30.95-7.0.0_374.gb8e8e6af-6.4.1

docker push engineerbetter/concourse:opensuse-42.3-51.g7fef1b7-30.95-7.0.0_374.gb8e8e6af-6.4.1

If you’re going to be building images with Fissile via CI, we have a reusable Concourse task and Bash script for that.

3. Create ConfigMaps

3.1 The BOSH Manifest

This will look similar to the BOSH deployment manifest you’re used to, but in this case it’s a ConfigMap - a first class Kubernetes resource. Some translation is need to adapt a BOSH deployment manifest for use with Quarks, but this conversion it covered in detail in the Quarks documentation.

For these sections it’s useful to have an example open for reference, this Redis deployment from Dr Nic is a good example.

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: redis-manifest
data:
  manifest: |
    ---
    name: redis
    addons:
    - name: bpm
      jobs:
      - name: bpm
        release: bpm
    instance_groups:
    - name: redis
      azs: [z1]
      instances: 2
      vm_type: default
      stemcell: default
      persistent_disk: 10240
      networks: [{name: default}]
      jobs:
      - name: redis
        release: redis
        properties:
          password: ((redis-password))
    - name: sanity-tests
      azs: [z1]
      instances: 1
      lifecycle: errand
      vm_type: default
      stemcell: default
      networks: [{name: default}]
      jobs:
      - name: sanity-tests
        release: redis
    variables:
    - name: redis-password
      type: password
    update:
      canaries: 0
      max_in_flight: 1
      serial: true
      canary_watch_time: 1000-20000
      update_watch_time: 1000-20000
    stemcells:
    - alias: default
      os: ubuntu-xenial
      version: 456.latest
    releases:
    - name: bpm
      sha1: c956394fce7e74f741e4ae8c256b480904ad5942
      url: git+https://github.com/cloudfoundry/bpm-release
      version: 1.1.8
    - name: redis
      sha1: 9ad77d700cf773ae47328c99eddb80d83648b57d
      stemcell:
        os: ubuntu-xenial
        version: "456.3"
      url: https://s3.amazonaws.com/redis-boshrelease/compiled-releases/
           redis/redis-15.3.3-ubuntu-xenial-456.3-20190815-004641-067837581-20190815004641.tgz
      version: 15.3.3

Quarks requires that a BOSH release uses BOSH Process Management (BPM), without this your deployment will fail. However, BPM _can_ be added via an ops file at runtime, so doesn't need to be written into the release itself.

3.2 Ops Files

Another BOSH native concept implemented as a ConfigMap. Ops files are utilised to overwrite, add, or remove aspects of the BOSH manifest, allowing a single central manifest to be customised for different environments and requirements.

Ops Files are also a means to satisfy the Quarks BPM requirement without writing BPM into the release.

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: my-ops-file
data:
  ops: |
    - type: remove
      path: /releases/name=my-release/sha1
    - type: replace
      path: /releases/name=my-release/url
      value: docker.io/cfcommunity

4. Create the boshdeployment

This is the one that the cf-operator is looking for, and is the culmination of all of the above. This resource tells the cf-operator which ConfigMap to use for the BOSH manifest, which Ops File ConfigMaps to include, any additional objects like Services need not be referenced here - they’ll be created alongside.

---
apiVersion: quarks.cloudfoundry.org/v1alpha1
kind: BOSHDeployment
metadata:
  name: my-deployment
spec:
  manifest:
    name: my-manifest
    type: configmap
  ops:
  - name: my-ops-file
    type: configmap
  - name: my-other-ops-file
    type: configmap

Services

While Services aren’t a requirement, they’ll expose your deployment so that it can be accessed outside of the cluster, so often I define the Service alongside the other Quarks objects. When testing deployments in the first instance it’s often easiest to add a ClusterIP Service, this can be substituted for other implementations later.

---
apiVersion: v1
kind: Service
metadata:
  name: my-service
spec:
  type: ClusterIP
  selector:
    quarks.cloudfoundry.org/instance-group-name: my-instance-group
    quarks.cloudfoundry.org/deployment-name: my-deployment
  ports:
    - protocol: TCP
      port: 6379
      targetPort: 6379

5. Pull the trigger

Once you’ve got all of your resources defined in a yaml file you can go ahead and run kubectl apply, making sure that you target the namespace your cf-operator is watching.

If you run a watch kubectl get all -n mynamespace you’ll be able to see your resources coming up as they’re created by the cf-operator, ending with your deployment running happily.

A gif of a terminal showing Redis being deployed with Quarks
Redis installation with Quarks `cf-operator`

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