This is a kubectl plugin to just say Hello World.
It is based on kubernetes/sample-cli-plugin and demonstrates the following topics:
- How to integrate k8s packages using Go Modules (e.g.
k8s.io/cli-runtimeandk8s.io/client-go). - How to make a kubectl plugin.
- How to ship a kubectl plugin as a Homebrew formula.
Download the latest release and extract kubectl-hello_world from the archive:
curl -LO https://github.com/int128/kubectl-hello-world/releases/download/v1.0.4/kubectl-hello_world_linux_amd64.zip
unzip kubectl-hello_world_linux_amd64.zipor install by Homebrew tap:
brew tap int128/kubectl-hello-world
brew install kubectl-hello-worldor install by krew:
curl -LO https://github.com/int128/kubectl-hello-world/releases/download/v1.0.4/hello-world.yaml
kubectl krew install --manifest hello-world.yamlExamples:
% kubectl hello-world
I0328 10:07:22.492909 4901 cmd.go:47] Hello World from example.k8s.local
% kubectl hello-world --help
I0328 10:07:28.928283 4915 cmd.go:25] Help:
Usage: kubectl-hello_world [options] [args...]
A kubectl plugin just saying Hello World!
Options:
--as string Username to impersonate for the operation
--as-group stringArray Group to impersonate for the operation, this flag can be repeated to specify multiple groups.
--cache-dir string Default HTTP cache directory (default "~/.kube/http-cache")
--certificate-authority string Path to a cert file for the certificate authority
--client-certificate string Path to a client certificate file for TLS
--client-key string Path to a client key file for TLS
--cluster string The name of the kubeconfig cluster to use
--context string The name of the kubeconfig context to use
--insecure-skip-tls-verify If true, the server's certificate will not be checked for validity. This will make your HTTPS connections insecure
--kubeconfig string Path to the kubeconfig file to use for CLI requests. [$KUBECONFIG]
-n, --namespace string If present, the namespace scope for this CLI request
--request-timeout string The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests. (default "0")
-s, --server string The address and port of the Kubernetes API server
--token string Bearer token for authentication to the API server
--user string The name of the kubeconfig user to use
If name of the kubectl command contains -, you need to replace - with _.
For example,
kubectl hello-world
↓
/usr/local/bin/kubectl-hello_world
The latest version of k8s modules may break dependencies.
According to kubernetes/client-go#551,
fix tags in go.mod as follows:
require (
k8s.io/api kubernetes-1.13.2
k8s.io/apimachinery kubernetes-1.13.2
k8s.io/cli-runtime kubernetes-1.13.2
k8s.io/client-go v10.0.0
)
and run go mod tidy.
Some module causes checksum mismatch between GOOS such as macOS and Linux.
go: verifying k8s.io/client-go@v10.0.0+incompatible: checksum mismatch
downloaded: h1:F1IqCqw7oMBzDkqlcBymRq1450wD0eNqLE9jzUrIi34=
go.sum: h1:+xQQxwjrcIPWDMJBAS+1G2FNk1McoPnb53xkvcDiDqE=
Exited with code 1
According to golang/go#27925, add the following command on CI for workaround.
sed -e '/^k8s.io\/client-go /d' -i go.sumThis is an open source software. Feel free to open issues and pull requests.
You can build and run this as follows:
% make
go build -o kubectl-hello_world
% make run
PATH="$PATH:$PWD" kubectl hello-world