kubernetes-the-hard-way/docs/02-client-tools.md

Installing the Client Tools

In this lab you will install the command line utilities required to complete this tutorial: jq, cfssl, cfssljson, kubectl, and set up a few shell functions.

Install jq

Install jq:

OS X

curl -o jq -L https://github.com/stedolan/jq/releases/download/jq-1.6/jq-osx-amd64

chmod +x jq

sudo mv jq /usr/local/bin/

Some OS X users may experience problems using the pre-built binaries in which case Homebrew might be a better option:

brew install jq

Linux

curl -o jq -L https://github.com/stedolan/jq/releases/download/jq-1.6/jq-linux64

chmod +x jq

sudo mv jq /usr/local/bin/

Install CFSSL

The cfssl and cfssljson command line utilities will be used to provision a PKI Infrastructure and generate TLS certificates.

Download and install cfssl and cfssljson:

OS X

curl -o cfssl https://storage.googleapis.com/kubernetes-the-hard-way/cfssl/1.4.1/darwin/cfssl
curl -o cfssljson https://storage.googleapis.com/kubernetes-the-hard-way/cfssl/1.4.1/darwin/cfssljson

chmod +x cfssl cfssljson

sudo mv cfssl cfssljson /usr/local/bin/

Some OS X users may experience problems using the pre-built binaries in which case Homebrew might be a better option:

brew install cfssl

Linux

wget -q --show-progress --https-only --timestamping \
  https://storage.googleapis.com/kubernetes-the-hard-way/cfssl/1.4.1/linux/cfssl \
  https://storage.googleapis.com/kubernetes-the-hard-way/cfssl/1.4.1/linux/cfssljson

chmod +x cfssl cfssljson

sudo mv cfssl cfssljson /usr/local/bin/

Verification

Verify cfssl and cfssljson version 1.4.1 or higher is installed:

cfssl version

output

Version: 1.4.1
Runtime: go1.12.12

cfssljson --version

Version: 1.4.1
Runtime: go1.12.12

Install kubectl

The kubectl command line utility is used to interact with the Kubernetes API Server. Download and install kubectl from the official release binaries:

OS X

curl -o kubectl https://storage.googleapis.com/kubernetes-release/release/v1.18.6/bin/darwin/amd64/kubectl

chmod +x kubectl

sudo mv kubectl /usr/local/bin/

Linux

wget https://storage.googleapis.com/kubernetes-release/release/v1.18.6/bin/linux/amd64/kubectl

chmod +x kubectl

sudo mv kubectl /usr/local/bin/

Verification

Verify kubectl version 1.18.6 or higher is installed:

kubectl version --client

output

Client Version: version.Info{Major:"1", Minor:"18", GitVersion:"v1.18.6", GitCommit:"dff82dc0de47299ab66c83c626e08b245ab19037", GitTreeState:"clean", BuildDate:"2020-07-15T16:58:53Z", GoVersion:"go1.13.9", Compiler:"gc", Platform:"linux/amd64"}

Shell Helper Functions

In your terminal, run the following to define a few shell helper functions that we'll use throughout the tutorial:

function oci-fetch-public-ip(){
  # Helper function to fetch and stash the public IP for the given OCI compute instance
  if [ -z "$1" ]
  then
    echo "Usage: oci-fetch-public-ip <compute_instance_name> <optional_command>"
  else
    file=.kubernetes-the-hard-way/$1/public_ip
    if [ ! -f "$file" ] || [ ! -s "$file" ];
    then
        # Fetch the public IP and stash it for quick lookup by later commands
        echo "Fetching $1 Public IP..."
        mkdir -p .kubernetes-the-hard-way/$1
        ocid=$(oci compute instance list --lifecycle-state RUNNING --display-name $1 \
          | jq -r .data[0].id)
        oci compute instance list-vnics --instance-id $ocid | jq -r '.data[0]["public-ip"]' \
          > .kubernetes-the-hard-way/$1/public_ip 
    fi      
  fi
}

function oci-ssh(){
  # Helper function to ssh into a named OCI compute instance
  if [ -z "$1" ]
  then
    echo "Usage: oci-ssh <compute_instance_name> <optional_command>"
  else
    oci-fetch-public-ip $1
    public_ip=$(cat .kubernetes-the-hard-way/$1/public_ip)   
    ssh -i kubernetes_ssh_rsa ubuntu@$public_ip $2
  fi
}

function oci-scp(){
  # Helper function to scp a set of local files to a named OCI compute instance
  if [ -z "$3" ]
  then
    echo "Usage: oci-scp <local_file_list> <compute_instance_name> <destination>"
  else
    oci-fetch-public-ip ${@: (-2):1}
    public_ip=$(cat .kubernetes-the-hard-way/${@: (-2):1}/public_ip)   
    scp -i kubernetes_ssh_rsa "${@:1:$#-2}" ubuntu@$public_ip:${@: -1}
  fi
}

For convenience throughout the rest of this tutorial, you can copy the above functions into your shell's profile, to avoid having to redefine them in each of the various tmux terminals we'll create. For example, for Bash shell, copy and past the above functions into ~/.bashrc, then refresh the profile from your current terminal session with:

. ~/.bashrc

Next: Provisioning Compute Resources