context | ||
docs | ||
example | ||
templater | ||
util | ||
.gitignore | ||
.travis.yml | ||
LICENSE | ||
main.go | ||
README.md |
Kontemplate - A simple Kubernetes templater
Kontemplate is a simple CLI tool that can take sets of Kubernetes resource files with placeholders and insert values per environment.
This tool was made because in many cases all I want in terms of Kubernetes configuration is simple value interpolation per environment (i.e. Kubernetes cluster), but with the same deployment files.
In my experience this is often enough and more complex solutions such as Helm are not required.
Overview
Kontemplate lets you describe resources as you normally would in a simple folder structure:
.
├── prod-cluster.yaml
└── some-api
├── deployment.yaml
└── service.yaml
This example has all resources belonging to some-api
(no file naming conventions enforced at all!) in the some-api
folder and the configuration for the cluster prod-cluster
in the corresponding file.
Lets take a short look at prod-cluster.yaml
:
---
context: k8s.prod.mydomain.com
global:
globalVar: lizards
include:
- name: some-api
values:
version: 1.0-0e6884d
importantFeature: true
apiPort: 4567
Those values are then templated into the resource files of some-api
. That's it!
You can also set up more complicated folder structures for organisation, for example:
.
├── api
│ ├── image-api
│ │ └── deployment.yaml
│ └── music-api
│ └── deployment.yaml
│ │ └── default.json
├── frontend
│ ├── main-app
│ │ ├── deployment.yaml
│ │ └── service.yaml
│ └── user-page
│ ├── deployment.yaml
│ └── service.yaml
├── prod-cluster.yaml
└── test-cluster.yaml
And selectively template or apply resources with a command such as
kontemplate apply test-cluster.yaml --include api --include frontend/user-page
to only update the api
resource sets and the frontend/user-page
resource set.
Installation
Assuming you have Go configured correctly, you can simply go get github.com/tazjin/kontemplate/...
.
There are signed binary releases available on the releases page for Linux, OS X and Windows.
Usage
You must have kubectl
installed to use Kontemplate effectively.
usage: kontemplate [<flags>] <command> [<args> ...]
simple Kubernetes resource templating
Flags:
-h, --help Show context-sensitive help (also try --help-long and --help-man).
-i, --include=INCLUDE ... Resource sets to include explicitly
-e, --exclude=EXCLUDE ... Resource sets to exclude explicitly
Commands:
help [<command>...]
Show help.
template <file>
Template resource sets and print them
apply [<flags>] <file>
Template resources and pass to 'kubectl apply'
replace <file>
Template resources and pass to 'kubectl replace'
delete <file>
Template resources and pass to 'kubectl delete'
create <file>
Template resources and pass to 'kubectl create'
Examples:
# Look at output for a specific resource set and check to see if it's correct ...
kontemplate template example/prod-cluster.yaml -i some-api
# ... maybe do a dry-run to see what kubectl would do:
kontemplate apply example/prod-cluster.yaml --dry-run
# And actually apply it if you like what you see:
kontemplate apply example/prod-cluster.yaml