Enable nested virtualization on GKE (be careful when running)

enable_vmx.sh

#!/bin/bash
set -o errexit
set -o nounset
set -o pipefail

# $IG_URLS as env

# GET auth token to be used in curl/rest api
AUTH_TOKEN=$(gcloud auth print-access-token)

function isGoogResExists {
  PARAMS=(
    -s
    -I
    -o /dev/null
    -w "%{http_code}"
    -H "Authorization: Bearer ${AUTH_TOKEN}"
    -H "Content-Type: application/json"
  )
  status_code=$(curl "${PARAMS[@]}" $1);
  if [ $status_code -eq 404 ]; then
    return 1
  elif [ $status_code -eq 200 ]; then
    return 0
  fi
}

function makeGoogGetReq {
  PARAMS=(
    -s
    -H "Authorization: Bearer ${AUTH_TOKEN}"
    -H "Content-Type: application/json"
  )
  curl "${PARAMS[@]}" $1;
}

function makeGoogPostReq {
  PARAMS=(
    -s
    -XPOST
    -H "Authorization: Bearer ${AUTH_TOKEN}"
    -H "Content-Type: application/json"
  )
  curl "${PARAMS[@]}" $1 --data "$2";
}


# Loop over intances group urls
for igurl in ${IG_URLS//,/ }; do
  # GET instance template from instance group
  it_url=$(makeGoogGetReq $igurl | jq -r .instanceTemplate);
  BASE_IT_URL="${it_url%/instanceTemplates*}/instanceTemplates"
  it_json=$(makeGoogGetReq $it_url);

  # STEP 1: DUPLICATE INSTANCE TEMPLATE
  it_name=$(echo $it_json | jq -r '.name')
  if [[ "$it_name" != *-vmx ]]; then
    it_name="${it_name}-vmx";
  fi
  new_it_url="${BASE_IT_URL}/${it_name}"
  if isGoogResExists "$new_it_url"; then
    echo "Instance Template exists.."
  else
    echo "Creating new InstanceTemplate.."
    extra_pkg=(
      'apt-get update && '
      'apt-get install -y '
      'qemu-kvm libvirt-bin ubuntu-vm-builder bridge-utils'
    );
    printf -v _extra_pkg "%s" "${extra_pkg[@]}";
    OPS=(
      '.name = $it_name'
      '.properties.advancedMachineFeatures.enableNestedVirtualization = true'
      '(.properties.metadata.items[] | select(.key == "configure-sh") | .value) += $extra_pkg'
      '(.properties.metadata.items[] | select(.key == "configure-sh") | .value) += "\n"'
    )
    printf -v _OPS " | %s" "${OPS[@]}"
    ARGS=(
      --arg it_name "$it_name"
      --arg extra_pkg "$_extra_pkg"
    )
    new_it_json=$(echo "$it_json" | jq -r ". $_OPS" "${ARGS[@]}");
    makeGoogPostReq $BASE_IT_URL "$new_it_json"

  fi

  # STEP 2: UPDATE INSTANCE GROUP WITH NEW INSTANCE TEMPLATE
  if [[ $(makeGoogGetReq "$igurl" | jq -r .instanceTemplate) == "$new_it_url" ]]; then
    echo "InstanceGroup up-to-date"
  else
    # UPDATE IG with new IT
    echo "Updating InstanceGroup with ${new_it_url}.."
    body=$(printf '{"instanceTemplate": "%s"}' "$new_it_url")
    makeGoogPostReq "$igurl/setInstanceTemplate" "$body"
    echo "InstanceGroup updated!"

    until [ $(makeGoogGetReq "$igurl" | jq -r .instanceTemplate) == "$new_it_url" ]; do
      echo "Waiting new InstanceTemplate to get applied.."
      sleep 3
    done

    # STEP 3: RECREATE/REPLACE INSTANCES in IG
    body='{"allInstances": "true", "minimalAction":"REPLACE"}'
    makeGoogPostReq "$igurl/applyUpdatesToInstances" "$body"
    echo "InstanceGroup instances recreate request sent!"
  fi

done