Use k8s-args.root-dir in drain script when watching for PVC detach (#314

)

Added a spec test to verify the behavior.

jobs/kubelet/templates/bin/drain.erb

@@ -45,7 +45,10 @@ drain_node() {
 }
 
 get_k8s_disks() {
-  disks=$(lsblk -dnl -o NAME,TYPE,MOUNTPOINT | awk '/var\/lib\/kubelet/ {print $1}')
+<%-
+  root_dir = p('k8s-args', {}).fetch('root-dir', "/var/lib/kubelet").gsub("/", "\\/")
+-%>
+  disks=$(lsblk -dnl -o NAME,TYPE,MOUNTPOINT | awk '/<%= root_dir %>/ {print $1}')
   echo ${disks[@]} | tr " " "|"
 }
 

spec/kubelet_drain_spec.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'rspec'
+require 'spec_helper'
+
+def get_k8s_disks_dir(rendered_drain)
+  lsblk_line = rendered_drain.split("\n").select { |line| line[/MOUNTPOINT/i] }
+  expect(lsblk_line.length).to be(1)
+  lsblk_line[0].match(/awk '\/(.+)\/ {print \$1}'/).captures[0]
+end
+
+describe 'kubelet drain' do
+
+  it 'substitutes in the k8s-args.root-dir property for get_k8s_disks()' do
+    manifest_properties = {
+      'k8s-args' => {
+        'root-dir' => '/var/vcap/data/kubelet'
+      }
+    }
+
+    rendered_drain = compiled_template('kubelet', 'bin/drain', manifest_properties, {}, {}, nil, nil, nil)
+    k8s_disks_dir = get_k8s_disks_dir(rendered_drain)
+    expect(k8s_disks_dir).to eq(manifest_properties['k8s-args']['root-dir'].gsub("/", "\\/"))
+  end
+
+  it 'uses /var/lib/kubelet for get_k8s_disks() by default' do
+    rendered_drain = compiled_template('kubelet', 'bin/drain', {}, {}, {}, nil, nil, nil)
+    k8s_disks_dir = get_k8s_disks_dir(rendered_drain)
+    expect(k8s_disks_dir).to eq("/var/lib/kubelet".gsub("/", "\\/"))
+  end
+end