unikorn

Unikorn

A badass, opinionated, deployer of souls!

Overview

Resources

Unikorn abstracts away installation of Cluster API.

There are three resource types:

• Projects, that are a container for higher level abstractions.
• ControlPlanes, that basically are instances of Cluster API that live in Projects.
• Clusters, Kubernetes clusters.

Control planes are actually contained themselves in virtual clusters, as CAPI is pretty terrible at cleaning things up on OpenStack errors, so we make these cattle. One Kubernetes cluster to one instance of Cluster API. If something goes wrong, just delete the virtual cluster and restart. In future, when things get more stable, we can support many-to-one to save on resource costs, and even do away with virtual clusters entirely.

Projects allow multiple control planes to be contained within them. These are useful for providing a boundary for billing etc.

Unsurprisingly, as we are dealing with custom resources, we are managing the lifecycles as Kubernetes controllers ("operator pattern" to those drinking the CoreOS Koolaid).

Services

Unikorn is split up into domain specific micro-services:

• Project, control plane and cluster controllers. These are reactive services that watch for resource changes, then reconcile reality against the requested state.
• Server is a RESTful interface that manages Unikorn resource types. It additionally exposes a limited, and opinionated, set of OpenStack interfaces that provide resources that are used to populate required fields in Unikorn resources. As it's intended as a public API e.g. for Terraform or a user interface, it integrates authn/authz functionality too.
• UI is a user interface, and provides a seamless and intuitive UX on top of server. This adds even more opinionation on top of the REST interface. This is hosted in a separate repository.
• Monitor is a daemon that periodically polls Unikorn resource types, and provides functionality that cannot be triggered by reactive controllers. Most notably, this includes automatic upgrades.

Installation

Installing the Management Binary

NOTE: You are better off installing Unikorn Server/UI as a shell, see below for details.

Download the official binary (update the version as appropriate):

wget -O ~/bin/unikornctl https://github.com/eschercloudai/unikorn/releases/download/v0.3.61/unikornctl-linux-amd64

Set up shell completion

unikornctl has a large amount of convenience and contextual awareness built into its various subcommands. It's strongly recommended to set up shell completion to make your life a lot easier.

export TEMP=$(mktemp)
unikornctl completion bash > ${TEMP}
source ${TEMP}

autoload -U +X compinit && compinit
unikornctl completion zsh > $fpath/_unikornctl

fpath=( ~/.zshfunc "${fpath[@]}" )

Installing the Service

Is all done via Helm, which means we can also deploy using ArgoCD. As this is a private repository, we're keeping the charts private for now also, so you'll need to either checkout the correct branch for a local Helm installation, or imbue Argo with an access token to get access to the repository.

Installing ArgoCD

ArgoCD is a required to use Unikorn.

Deploy argo using Helm (the release name is hard coded, don't change it yet please):

helm repo add argo https://argoproj.github.io/argo-helm
helm repo update
helm install argocd argo/argo-cd -n argocd --create-namespace

Installing Prerequisites

The Unikorn server component has a couple prerequisites that are required for correct functionality. If not installing server you can skip to the next section.

You'll need to install:

• cert-manager (used to generate keying material for JWE/JWS and for ingress TLS)
• nginx-ingress (to perform routing, avoiding CORS, and TLS termination)

helm repo add jetstack https://charts.jetstack.io
helm repo add nginx https://helm.nginx.com/stable
helm repo update
helm install cert-manager jetstack/cert-manager -v v1.10.1 -n cert-manager --create-namespace
helm install nginx-ingress nginx/nginx-ingress -v 0.16.1 -n nginx-ingress --create-namespace

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: cert-manager
  namespace: argocd
spec:
  project: default
  source:
    chart: cert-manager
    helm:
      parameters:
      - name: installCRDs
        value: "true"
      releaseName: cert-manager
    repoURL: https://charts.jetstack.io
    targetRevision: v1.10.1
  destination:
    name: in-cluster
    namespace: cert-manager
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
    - CreateNamespace=true
---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: nginx-ingress
  namespace: argocd
spec:
  project: default
  source:
    chart: nginx-ingress
    helm:
      parameters:
      - name: controller.service.httpPort.enable
        value: "false"
      releaseName: nginx-ingress
    repoURL: https://helm.nginx.com/stable
    targetRevision: 0.16.1
  destination:
    name: in-cluster
    namespace: nginx-ingress
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
    - CreateNamespace=true

Installing Unikorn

NOTE: Unikorn Server is not installed by default, see below for details.

You can install using the local repo, or with CD.

First, unless you are doing local development and want to manually load images, you will want to configure image pull secrets in order to be able to pull the images. Create a GitHub personal access token that has the read:packages scope, then add it to your ~/.docker/config.json:

docker login ghcr.io --username spjmurray --password ghp_blahBlahBlah

Then install Unikorn:

helm install unikorn charts/unikorn --namespace unikorn --create-namespace --set dockerConfig=$(base64 -w0 ~/.docker/config.json)

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: unikorn
  namespace: argocd
spec:
  project: default
  source:
    path: charts/unikorn
    repoURL: https://github.com/eschercloudai/unikorn
    targetRevision: v0.3.61
    helm:
      parameters:
      - name: dockerConfig
        value: # output of "base64 -w0 ~/.docker/config.json"
  destination:
    namespace: unikorn
    server: https://kubernetes.default.svc
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
    - CreateNamespace=true

Installing Unikorn Server

To enable it add the parameter --set server.enabled=true. This will install a developer version of the server with a self-signed certificate.

Rudimentary support exists for ACME certificates using the DNS01 protocol. Only Cloudflare has been implemented and tested.

A typical values.yaml that uses ACME could look like:

server:
  enabled: true
  host: kubernetes.my-domain.com
  acme:
    email: spam@my-domain.com
    server: https://acme-v02.api.letsencrypt.org/directory
    cloudflare:
      email: cloudflare-user@my-domain.com
      apiToken: bW92ZV9hbG9uZ19jbGV2ZXJfZGljaw==

The host defines the X.509 SAN, and indeed the host the Ingress will respond to. There is no automated DDNS yet, so you will need to manually add the A record when the ingress comes up.

The server shown is the production server, and will be trusted by browsers. You can use the acme-staging-v02 host if just playing around as it's not as badly rate limited.

Finally the API token you will need to configure to allow editing of records in your domain. It's base64 encoded e.g. echo -n MY_TOKEN | base64 -w0.

Installing Unikorn UI

To enable Unikorn UI --set ui.enabled=true. This only enables the ingress route for now. You will also need to install the UI using Helm as described in the unikorn-ui repository. It must be installed in the same namespace as Unikorn server in order for the service to be seen by the Ingress.

Monitoring & Logging

• Prometheus monitoring can be enabled with the --set monitoring.enabled=true flag.
• OTLP (e.g. Jaeger) tracing can be enabled with the set server.otlpEndpoint=jaeger-collector.default:4318 flag.

See the monitoring & logging documentation from more information on configuring those services in the first instance..

Documentation

CLI

All the best tools document themselves, try:

unikornctl --help
unikornctl create --help

API (Unikorn Server)

Consult the server readme to get started.

Development

Consult the developer documentation for local development instructions.

The architecture documentation details how it all works, and the design considerations.