ksonnet

A tool for managing Kubernetes resources as code.

ksonnet allows you to express the patterns across your infrastructure and reuse these powerful "templates" across many services, and then manage those templates as files in version control. The more complex your infrastructure is, the more you will gain from using kubecfg.

Status: Basic functionality works, and the tool is usable. The focus now is on clearer error reporting and advanced features.

Install

Pre-compiled executables exist for some platforms on the Github releases page.

To build from source:

% PATH=$PATH:$GOPATH/bin
% go get github.com/ksonnet/ksonnet

Requires golang >=1.7 and a functional cgo environment (C++ with libstdc++). Note that recent OSX environments require golang >=1.8.1 to avoid an immediate Killed: 9.

Quickstart

# Include <ksonnet.git>/lib in ksonnet/jsonnet library search path.
# Can also use explicit `-J` args everywhere.
% export KUBECFG_JPATH=/path/to/ksonnet/lib

# Show generated YAML
% ks show -o yaml -f examples/guestbook.jsonnet

# Create resources
% ks apply -f examples/guestbook.jsonnet

# Modify configuration (downgrade gb-frontend image)
% sed -i.bak '\,gcr.io/google-samples/gb-frontend,s/:v4/:v3/' examples/guestbook.jsonnet
# See differences vs server
% ks diff -f examples/guestbook.jsonnet

# Update to new config
% ks apply -f examples/guestbook.jsonnet

# Clean up after demo
% ks delete -f examples/guestbook.jsonnet

Features

• Supports JSON, YAML or jsonnet files (by file suffix).
• Best-effort sorts objects before updating, so that dependencies are pushed to the server before objects that refer to them.
• Additional jsonnet builtin functions. See lib/kubecfg.libsonnet.

Infrastructure-as-code Philosophy

The idea is to describe as much as possible about your configuration as files in version control (eg: git).

Changes to the configuration follow a regular review, approve, merge, etc code change workflow (github pull-requests, phabricator diffs, etc). At any point, the config in version control captures the entire desired-state, so the system can be easily recreated in a QA cluster or to recover from disaster.

Jsonnet

ksonnet relies heavily on jsonnet to describe Kubernetes resources, and is really just a thin Kubernetes-specific wrapper around jsonnet evaluation. You should read the jsonnet tutorial, and skim the functions available in the jsonnet std library.