pkg.gl

Description

Scripting-friendly tool to work with multiple k8s clusters, with ability to provide a concise way to write system documentation, to avoid human mistake and finally, to improve team communication and work.

Ideas

The known way

$ export KUBECONFIG=~/.kube/config:~/.kube/kubconfig2
$ kubectl config use-context my-context
$ kubectl get nodes

This new way

$ gk8s :my-cluster get nodes

The tool doesn't accept delete action by default. You must touch a local file .delete or using environment setting DELETE=true to activate the deletion:

$ gk8s :my-cluster delete pod foo
:: Error: File .delete doesn't exist in the current directory.

$ touch .delete; gk8s :my-cluster delete pod foo
Error from server (NotFound): pods "foo" not found

$ DELETE=true gk8s :my-cluster delete pod foo
Error from server (NotFound): pods "foo" not found

Touching file .delete doesn't support multiple actions in parallel.

Why

Improve communication
Easy to write examples in documentation
Design for scripting purpose
Slow down dangerous commands by default
Have fun with Golang
Somebody hates shell scripting :D
Just don't have everything in ~/.kube/config

Getting started

$ go get github.com/icy/gk8s
$ mkdir -pv ~/.config/gk8s/
$ ln -sv /path/to/cluster-config ~/.config/gk8s/my-cluster

Repeat the last steps for any other cluster.

Examples

The following commands yield the same result:

$ gk8s :cluster get nodes
$ gk8s :cluster kubectl get nodes
$ gk8s :cluster -- kubectl get nodes

Some notes

The command kubectl is used by default.
When you specify --, the remain part is invoked.
If cluster is local, the defaulf configuration is used (aka, when KUBECONFIG is empty.)

If you want to use with helm:

$ gk8s :cluster -- helm <additional-arguments>

Now let's work with multiple clusters on the same command: For example, to compare configurations on two clusters, let's go with diff:

$ colordiff <(gk8s :cluster1 get foo -n bar -o yaml) <(gk8s :cluster2 get foo -n bar -o yaml)

Switching context? Environment variable? You would get quite a lot of troubles here ;)

How it works

Each cluster/context has their own configuration file under the directory $GK8S_HOME (which is ~/.config/gk8s/ by default). Working with the cluster is simply by invoking

$ gk8s :<cluster> command-and-or-arguments

for example

$ gk8s :production get pods

would look up configuration in ~/.config/gk8s/production and execute the command kubectl get pods accordingly.

If cluster is local, the command will use empty value for KUBECONFIG, that means the configuration is supposed to be ~/.kube/config.

Using this program as a script

$ go get github.com/erning/gorun
$ sudo mv ~/go/bin/gorun /usr/local/bin/
$ echo ':golang:E::go::/usr/local/bin/gorun:OC' | sudo tee /proc/sys/fs/binfmt_misc/register
:golang:E::go::/usr/local/bin/gorun:OC

Alternatives

You can use some shell script, some aliases, bla bla. You can also write a simple function to update KUBECONFIG variable for your cluster before getting started, for example, in .bash.

(Note, the following script doesn't have advanced feature as the golang tool.)

$ my_gk8s() {
  cluster="${1:-}"
  if [[ "${cluster:0:1}" == ":" ]]; then
    cluster="${cluster:1}"
    shift
  else
    echo >&2 ":: Missing cluster name."
    return
  fi
  export KUBECONFIG="$HOME/.config/gk8s/$cluster"
  kubectl "$@"
}

$ my_gk8s :my-cluster get pods

Authors. License. Misc

The author is Ky-Anh Huynh.

This work is released under a MIT license.

This program is the Golang version of my Bashy thing https://github.com/icy/bashy/blob/master/bin/gk8s. New version is written as an answer to the known problem: Someone really hates Bash :)

# README