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.
Check out a Kontemplate setup example and the feature list below!
Table of Contents
- Kontemplate - A simple Kubernetes templater
- Simple, yet powerful templates
- Clean cluster configuration files
- Resources organised as simple resource sets
- Integration with pass
- Integration with kubectl
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
folder and the configuration for the cluster
prod-cluster in the corresponding file.
Lets take a short look at
--- 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.
It is recommended to install Kontemplate from the Nix package set,
where it is available since NixOS 17.09 as
If using Nix is not an option for you, several other methods of installation are available:
Signed binary releases are available on the releases page for Linux, OS X, FreeBSD and Windows.
Releases are signed with the GPG key
Building from source
You can clone Kontemplate either by cloning the full TVL [depot][https://code.tvl.fyi] or by just cloning the kontemplate subtree like so:
git clone https://code.tvl.fyi/depot.git:/ops/kontemplate.git
go tooling can be used as normal with this cloned repository. In
a full clone of the depot, Nix can be used to build Kontemplate:
nix-build -A ops.kontemplate
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'
# 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
Check out the feature list and the individual feature documentation above. Then you should be good to go!
Feel free to contribute pull requests, file bugs and open issues with feature suggestions!
Kontemplate is licensed under the GPLv3, a copy of the license and its terms can be found
Please follow the code of conduct.