Skip to content
forked from Eneco/landscaper

Takes a set of Helm Chart references with values (a desired state), and realizes this in a Kubernetes cluster

License

Notifications You must be signed in to change notification settings

royjs/landscaper

 
 

Repository files navigation

Landscaper

Build Status Go Report Card Go Doc Say Thanks!

Landscaper takes a set of Helm Chart references with values (a desired state), and realizes this in a Kubernetes cluster. The intended use case is to have this desired state under version control, and let Landscaper first test and then apply the state as part of the CI/CD stages.

The Landscaper project is an ongoing project in an early stage, opened due to demand in the community. Contributions and feedback are more than welcome!

Introduction

Why

  • The set of applications in the Kubernetes cluster is potentially large and complex;
  • Manually inspecting and administering them, and keeping different environments (e.g. production, acceptance) in sync is laborious and difficult;
  • Cooperating with multiple tenants in this shared cluster increases the complexity.

How

  • Have a blue print of what the landscape (apps in the cluster) looks like;
  • Keep track of changes: when, what, why and by who;
  • Allow others to review changes before applying them;
  • Let the changes be promoted to specific environments.

What

  • A Git repository contains a desired state description of the landscape, with CI/CD and a review before merge regime;
  • Landscaper, an app that eliminates difference between desired and actual state of Helm releases in a Kubernetes cluster.

Installation

Binaries are available here; Docker images here. On macOS using Homebrew, a brew install landscaper should do.

From source

You must have a working Go environment with glide and Make installed.

From a terminal:

  cd $GOPATH
  mkdir -p src/github.com/eneco/
  cd !$
  git clone https://github.com/Eneco/landscaper.git
  cd landscaper
  make bootstrap build

Outputs the landscaper binary in ./build/landscaper.

Usage

Landscaper consists of a core API and a command line interface (CLI) that consumes this API. It takes as input a set of files that constitute the desired state. The CLI assumes that kubectl and helm have been setup!

These files contain (a) reference(s) to a Helm Chart and its configuration (Values). Additionally, Landscaper receives settings (tokens, credentials) needed to query and modify a Kubernetes cluster via Helm/Tiller. Typically these settings are provided by the CI/CD system.

The CLI uses a command structure in the spirit of git et al. The main command is landscaper apply to apply a desired state. The apply command accepts the following arguments:

Usage:
  landscaper apply [files]... [flags]

Flags:
      --azure-keyvault string     azure keyvault for fetching secrets. Azure credentials must be provided in the environment.
      --chart-dir string          (deprecated; use --helm-home) Helm home directory (default "$HOME/.helm")
      --context string            the kube context to use. defaults to the current context
      --dir string                (deprecated) path to a folder that contains all the landscape desired state files; overrides LANDSCAPE_DIR
      --disable stringSlice       Stages to be disabled. Available stages are create/update/delete.
      --dry-run                   simulate the applying of the landscape. useful in merge requests
      --helm-home string          Helm home directory (default "$HOME/.helm")
      --env string                environment specifier. selects value overrides by environment.
      --loop                      keep landscape in sync forever
      --loop-interval duration    when running in a loop the interval between invocations (default 5m0s)
      --namespace string          namespace to apply the landscape to; overrides LANDSCAPE_NAMESPACE (default "default")
      --no-prefix                 disable prefixing release names
      --prefix string             prefix release names with this string instead of <namespace>; overrides LANDSCAPE_PREFIX
      --tiller-namespace string   Tiller namespace for Helm (default "kube-system")
  -v, --verbose                   be verbose
      --wait                      wait for all resources to be ready
      --wait-timeout duration     interval to wait for all resources to be ready (default 5m0s)

Instead of using arguments, environment variables can be used. When arguments are present, they override environment variables. --namespace is used to isolate landscapes through Kubernetes namespaces. Unless otherwise specified, Helm releases are prefixed with the same namespace string to avoid collisions, since Helm release names aren't namespaced. As of version 1.0.3, components can specify their namespace. This will override any provided global namespace.

Landscaper can also be run as a control loop that constantly watches the desired landscape and applies it to the cluster. With this you can deploy landscaper once in your cluster, pass it a reference to a landscape description and have Landscaper apply it whenever the landscape changes.

Connection to Tiller is made by setting up a port-forward to it's pod. However, when $HELM_HOST is defined with a "host:port" in it, a direct connection is made to that host and port instead.

Azure Credentials

When using the --azure-keyvault argument, Azure Service Principal credentials must be available in the environment:

  • AZURE_CLIENT_ID
  • AZURE_CLIENT_SECRET
  • AZURE_TENANT_ID

The key vault DNS suffix defaults to the public cloud, vault.azure.net, but can be overridden with AZURE_KEYVAULT_DNS_SUFFIX.

Desired State Files

Input desired state files are in YAML and contain the name that identifies the "component", a reference to a chart, configuration and optionally secrets.

name: my-component
release:
	chart: "example/chart:0.1.0"
	version: 0.1.0

# This will become the .Values override for the chart deployment.
configuration: 
  hostname: "example"
  url: "http://default.example.com"
  
# These configurations can be selected with the '--env' flag 
# and will override the above values. 
environments: 
  dev:
    url: "http://dev.example.com"
  prod:
    url: "http://prod.example.com"

# These secrets will be fetched, and instantiated as a Kubernetes 
# secret whose name will be written to .Values.secretsRef
secrets:     
- my-secret
- my-other-secret

Installing the above component with default prefix and --env dev will result in chart value overrides

hostname: "example"
url: "http://dev.example.com"
secretsRef: 'default-my-component'

and a Kubernetes secret named default-my-component with the contents:

my-secret: <value of MY_SECRET environment variable>
my-other-secret: <value MY_OTHER_SECRET environment variable>

Currently, secrets are handled by specifying the name in the YAML, e.g. my-secret, and having a matching environment variable available with the secret, e.g. export MY_SECRET=Rumpelstiltskin

Secret Usage in Helm Charts

Secrets are made available as Kubernetes Secrets (as shown above). The helm chart needs to be setup to use the secret in a pod, where the secret name is made available by the landscaper as .Values.secretsRef. For example, as an environment variable:

env:
- name: MY_SECRET
  valueFrom:
    secretKeyRef:
      name: {{ .Values.secretsRef }}
      key: my-secret

Or mounted volume:

volumes:
- name: my-secret
  secret:
    secretName: {{ .Values.secretsRef }}
    items:
    - key: my-secret
      path: secrets/my-secret
      mode: 511

Example

An example is provided here.

Example Use Case

We, at Eneco, have setup a git repository with the inputs to the landscaper. During CI, non-master branches are Landscaped --dry-run to validate the inputs. After a pull request is reviewed, the changes are merged into master after which the Landscaper applies the new desired state.

Example disable a stage

Landscaper is build on philosphy of applying charts in three stages delete, update and create and in that order.

However it allows to disable stages during apply. So users can cover their corner cases.

e.g to disable delete stage

landscaper apply [files] --disable delete

and to disable delete and update

landscaper apply [files] --disable delete --disable update

Compatibility

Landscaper uses both Helm and Kubernetes. The following Landscaper releases are built against the following versions:

Landscaper Helm Kubernetes
1.0.12 2.7.2 1.8
1.0.11 2.6.1 1.7
1.0.10 2.5.1 1.6
1.0.9 2.5.1 1.6
1.0.8 2.4.2 1.6
1.0.7 2.4.2 1.6
1.0.6 2.4.2 1.6
1.0.5 2.4.2 1.6
1.0.4 2.3.1 1.5
1.0.3 2.1.3 1.5
1.0.2 2.1.3 1.5
1.0.1 2.1.3 1.5
1.0.0 2.1.3 1.5

Contributing

We'd love to accept your contributions! Please use GitHub pull requests: fork the repo, develop and test your code, semantically commit (as of April 2017) and submit a pull request. Thanks!

About

Takes a set of Helm Chart references with values (a desired state), and realizes this in a Kubernetes cluster

Resources

License

Stars

Watchers

Forks

Packages

No packages published

Languages

  • Go 94.4%
  • Makefile 2.0%
  • Smarty 1.8%
  • Shell 1.8%