kubectl-chart

A kubectl plugin to ease management of cluster components using helm charts. Minimum required Kubernetes version currently is 1.13 for kubectl-chart to work.

This is still alpha quality and will likely change a lot, so be careful to use it in production. You have been warned.

More documentation for code and usage will be added soon.

Why?

The goal that kubectl-chart is trying to achieve is to ease the management of core cluster components like monitoring, operators, CNI, CI/CD tooling and the like. All common operations should only require a single command (e.g. render, diff and dry-run apply in one step). Lastly it should integrate some features not (yet) present in kubernetes (e.g. optional PVC deletion for stateful sets, lifecycle hooks and dry-run for deletions).

It is built as a single binary and is completely stateless. It is also well suited for integration into CI/CD because it provides dry-run and diff functionality for chart changes.

Features

• Render and apply multiple charts in one step
• Proper pruneing of resources removed from a chart (leveraging prune functionality of the kubectl apply command)
• Prettier resource diffs for charts (leveraging functionality of kubectl diff, enhanced by custom diff printer)
• Dry-run for chart deletions
• Diffs for deleted chart resources
• Resource diffs for all charts while dry-run and apply
• Simple chart lifecycle hooks (similar to helm hooks)
• Configurable pruning of PVC of deleted StatefulSets
• Dumping of merged chart values for debugging
• Color indicators for printed resource operations to increase visibility
• Delete chart resources by selector

Roadmap / Planned features

• Full integration test coverage
• Listing all deployed resources of a chart (similar to kubectl get all with filter)
• Automatic PersistentVolumeClaim resizing
• Optional rollback of partially applied changes on failure

Installation

After kubectl-chart is installed, it is available as a kubectl plugin under the command kubectl chart.

From source

git clone https://github.com/martinohmann/kubectl-chart
cd kubectl-chart
make install
kubectl chart version

This will install the kubectl-chart binary to $GOPATH/bin/kubectl-chart.

From binary release

Currently only Linux and MacOSX are packaged as binary releases.

curl -SsL -o kubectl-chart "https://github.com/martinohmann/kubectl-chart/releases/download/v0.0.2/kubectl-chart_0.0.2_$(uname -s | tr '[:upper:]' '[:lower:]')_x86_64"
chmod +x kubectl-chart
sudo mv kubectl-chart /usr/local/bin

You can verify the installation by printing the version:

kubectl chart version

Usage examples

Diff chart:

kubectl chart diff -f path/to/chart

Diff all charts in a directory:

kubectl chart diff -f path/to/charts -R

Dry run apply with chart value overrides:

kubectl chart apply -f path/to/chart --server-dry-run --values path/to/values.yaml

Dry run delete charts by filter:

kubectl chart delete -f path/to/charts -R --chart-filter chart1,chart3 --dry-run

Render chart:

kubectl chart render -f path/to/chart

Render chart hooks:

kubectl chart render -f path/to/chart --hook-type all

How does it work?

It is pretty simple. kubectl-chart adds a label to each chart resource it renders so it can identify resources belonging to a chart once they are deployed into a cluster. The label makes it possible to easily diff charts against the live objects and identify resources that were deleted from the chart but are still present in the cluster.

Using the label kubectl chart apply internally runs logic equivalent to kubectl apply --prune -l <chart-label-selector> to transparently prune removed resources.

License

The source code of kubectl-chart is released under the MIT License. See the bundled LICENSE file for details.