CODEWITHSUNDEEP
kuberneteskubectl
Assen Kolov
Assen Kolov

Reputation: 4393

How to configure kubectl with cluster information from a .conf file?

I have an admin.conf file containing info about a cluster, so that the following command works fine:

kubectl --kubeconfig ./admin.conf get nodes

How can I config kubectl to use the cluster, user and authentication from this file as default in one command? I only see separate set-cluster, set-credentials, set-context, use-context etc. I want to get the same output when I simply run:

kubectl get nodes

Upvotes: 106

Views: 317186

Answers (12)

Mohamed Gharib
Mohamed Gharib

Reputation: 2587

For quickly changing between config files on Windows, I wrote this PowerShell function :

# Change k8s config file (KUBECONFIG)
# kubeconf          Print current KUBECONFIG
# kubeconf $name    Select "$HOME\.kube\$name"
# kubeconf .        Select "config" in current dir
# kubeconf ./$name  Select $name in current dir
function kubeconf($name) {
  if ($name) {
    $path = "$HOME\.kube\$name"
    if ($name -eq '.') {
      $path = ".\config"
    } elseif ($name -is [string] -And $name.StartsWith('.')) {
      $path = $name
    }
    [Environment]::SetEnvironmentVariable('KUBECONFIG', "$path", 'User')
    $env:KUBECONFIG="$path"
  }

  echo $env:KUBECONFIG
}

Put this code in $HOME\Documents\PowerShell\Profile.ps1 (you might need to create the file if it doesn't already exist)

Now in a new PowerShell terminal, you can use the command kubeconf, here's some example usage:

kubeconf                  # Print current KUEBCONFIG
kubeconf cluster1-config  # Select "$HOME\.kube\cluster1-config"
kubeconf config           # Select default "$HOME\.kube\config"
kubeconf .                # Select "config" in current dir
kubeconf ./config2        # Select "config2" in current dir

It also persists the environment variable between sessions

Extra tip

While you're at it, you could add a couple of command aliases if you use k8s commands a lot:

Set-Alias k kubectl
Set-Alias kc kubeconf

# https://github.com/ahmetb/kubectx
Set-Alias kx kubectx
Set-Alias kn kubens

Upvotes: 0

Gleeb
Gleeb

Reputation: 11289

Here are the official documentation for how to configure kubectl

https://kubernetes.io/docs/concepts/configuration/organize-cluster-access-kubeconfig/

You have a few options, specifically to this question, you can just copy your admin.conf to ~/.kube/config

Upvotes: 74

Evgenii Zhuravlev
Evgenii Zhuravlev

Reputation: 125

This is possible:

export KUBECONFIG=~/.kube/config:~/.kube/cluster0:~/.kube/cluster1:~/.kube/cluster3

and:

kubectl config use-context  cluster0

Upvotes: 1

dehasi
dehasi

Reputation: 2773

When you type kubectl I guess you prefer to know which cluster you are pointing. Maybe it's worth creating an alias for that?

alias kube-mycluster='kubectl --kubeconfig ~/.kube/mycluster.conf'

Upvotes: 0

Iurasog Lucian
Iurasog Lucian

Reputation: 1

Manage your config files proper,place below in your profile file, source the .profile / .bash_profile

for kconfig in $HOME/.kube/config $(find $HOME/.kube/ -iname "*.config")
do
         if [ -f "$kconfig" ];then
                 export KUBECONFIG=$KUBECONFIG:$kconfig
         fi
 done

switch the contexts from kubectl

Upvotes: 0

Flavien Volken
Flavien Volken

Reputation: 21259

Kubernetes keeps the path to search for config files in $KUBECONFIG

If you want to add one more config path on top of the existing KUBECONFIG without overriding it (and keeping ~/.kube/config as the default path to search).

Just run the following each time you want to add a conf file to the KUBECONFIG path

export KUBECONFIG=${KUBECONFIG:-~/.kube/config}:/path/to/admin.conf

You can check it worked by listing the available contexts

kubectl config get-contexts

Then select the one you want to use

kubectl config use-context <context-name>

Upvotes: 3

Rotem jackoby
Rotem jackoby

Reputation: 22068

Because there is no built-in kubectl config merge command at the moment (follow this) you can add this function to your .bashrc (or .zshrc):

function kmerge() {
  if [ $# -eq 0 ]
   then
     echo "Please pass the location of the kubeconfig you wish to merge"
  fi
  KUBECONFIG=~/.kube/config:$1 kubectl config view --flatten > ~/.kube/mergedkub && mv ~/.kube/mergedkub ~/.kube/config
}

Then you can just run from termial:

kmerge /path/to/admin.conf

and the config file will be merged to ~/.kube/config.

You can now switch to the new context with:

kubectl config use-context <new-context-name>

Or if you're using kubectx (recommended) you can run: kubectx <new-context-name>.

(The kmerge function is based on @MichaelSp answer at this post).

Upvotes: 4

Exequiel Barrirero
Exequiel Barrirero

Reputation: 5848

Before answers have been very solid and informative, I will try to add my 2 cents here

Configure kubeconfig file knowing its precedence

If you’re using kubectl, here’s the preference that takes effect while determining which kubeconfig file is used.

  1. use --kubeconfig flag, if specified
  2. use KUBECONFIG environment variable, if specified
  3. use $HOME/.kube/config file

With this, you can easily override kubeconfig file you use per the kubectl command:

#
# using --kubeconfig flag
#
kubectl get pods --kubeconfig=file1
kubectl get pods --kubeconfig=file2

#
# or 
# using `KUBECONFIG` environment variable
#
KUBECONFIG=file1 kubectl get pods
KUBECONFIG=file2 kubectl get pods

#
# or 
# merging your kubeconfig file w/ $HOME/.kube/config (w/ cp backup)
#
cp $HOME/.kube/config $HOME/.kube/config.backup.$(date +%Y-%m-%d.%H:%M:%S)
KUBECONFIG= $HOME/.kube/config:file2:file3 kubectl config view --merge --flatten > \
~/.kube/merged_kubeconfig && mv ~/.kube/merged_kubeconfig ~/.kube/config
kubectl get pods --context=cluster-1
kubectl get pods --context=cluster-2

NOTE: The --minify flag allows us to extract only info about that context, and the --flatten flag allows us to keep the credentials unredacted.

For your example

kubectl get pods --kubeconfig=/path/to/admin.conf

#
# or:
#
KUBECONFIG=/path/to/admin.conf kubectl get pods

#
# or: 
#
cp $HOME/.kube/config $HOME/.kube/config.backup.$(date)
KUBECONFIG= $HOME/.kube/config:/path/to/admin.conf kubectl config view --merge --flatten > \
~/.kube/merged_kubeconfig && mv ~/.kube/merged_kubeconfig ~/.kube/config
kubectl get pods --context=cluster-1
kubectl get pods --context=cluster-2

Although this precedence list not officially specified in the documentation it is codified here. If you’re developing client tools for Kubernetes, you should consider using cli-runtime library which will bring the standard --kubeconfig flag and $KUBECONFIG detection to your program.

ref article: https://ahmet.im/blog/mastering-kubeconfig/

Upvotes: 27

Mirceac21
Mirceac21

Reputation: 1754

I name all cluster configs as .kubeconfig and this lives in project directory.

Then in .bashrc or .bash_profile I have the following export:

export KUBECONFIG=.kubeconfig:$HOME/.kube/config

This way when I'm in the project directory kubectl will load local .kubeconfig. Hope that helps

Upvotes: 13

Jeff Beagley
Jeff Beagley

Reputation: 1025

I just alias the kubectl command into separate ones for my dev and production environments via .bashrc

alias k8='kubectl'
alias k8prd='kubectl --kubeconfig ~/.kube/config_prd.conf'

I prefer this method as it requires me to define the environment for each command.. whereas using an environment variable could potentially lead you to running a command within the wrong environment

Upvotes: 45

stasdeep
stasdeep

Reputation: 3118

The best way I've found was to use an environment variable:

export KUBECONFIG=/path/to/admin.conf

Upvotes: 90

semekh
semekh

Reputation: 3917

kubectl uses ~/.kube/config as the default configuration file. So you could just copy your admin.conf over it.

Upvotes: 8

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