How to pass variable between Chef resource blocks of same recipe

Chef Infra (archive)
1

We have a Chef recipe with a couple resource blocks. The first resource block is in bash and gets the value of the UUID of a logical volume and stores into variable $uuid.

# Get UUID value
bash 'get uuid' do
  cwd "/"
  code <<-EOH
    uuid=$(blkid -o value -s UUID /dev/vg_volgroup/lv_logicalvolume)
  EOH
end

We need to pass the variable $uuid to our second resource block:

  # Mount directory, format, update fstab
  mount node['mount_dir'] do
    dump 1
    pass 2
    device #{uuid}
    device_type :uuid
    fstype node['fstype']
    options node['options']
    action [ :mount, :enable]
  end

Unfortunately, this is not working. The value of $uuid is not getting passed into the second resource block for device.

Is there a more proper way to reference $uuid from within the second resource block? Is what I’m asking even possible?

2

You could get the uuid from ohai. Try running “ohai filesystem2/by_device” from command line to see if you can get what you need. Then you could use something like node[‘filesystem2’][‘by_device’][‘YOUR_DEVICE’][‘uuid’] ohai attribute in your recipe.

3

Another option would be to set the uuid in ruby outside of your chef resource block, something like:

# Mount directory, format, update fstab
uuid = %x(/usr/sbin/blkid -o value -s UUID /dev/vg_volgroup/lv_logicalvolume)
mount node['mount_dir'] do
    dump 1
    pass 2
    device #{uuid}
    device_type :uuid
    fstype node['fstype']
    options node['options']
    action [ :mount, :enable]
end
4

Setting uuid in ruby like you do above is not working. Not able to get the device, or device does not exist. Maybe the syntax needs fixing?

The “ohai filesystem2/by_device” command does work, but trying to use the ohai attribute in my recipe is not working yet. I must not be constructing the attribute properly.

5

Actually, my ohai attribute path for the device was slightly off. I fixed it and now it works. Thanks much!

6

OK cool. For the other option, I forgot that ruby includes the newline, so I think this will work:

uuid = %x(/usr/sbin/blkid -o value -s UUID /dev/vg_volgroup/lv_logicalvolume).chomp

But I feel the ohai option is more the "chef way" in any case.

Glad to help.