Comment 6 for bug 1771382

Please see upstream bug report for all the details on this:

ds-identify: fails to recognize NoCloud datasource on boot cause it does not have /sbin in $PATH and thus does not find blkid
https://bugs.launchpad.net/cloud-init/+bug/1771382

Minimal patch to fix the issue:

slestemplate:~ # diff -u ds-identify.orig /usr/lib/cloud-init/ds-identify
--- ds-identify.orig 2018-05-16 13:34:06.376646777 +0200
+++ /usr/lib/cloud-init/ds-identify 2018-05-16 13:47:59.215541889 +0200
@@ -200,7 +200,7 @@
     fi
     local oifs="$IFS" line="" delim=","
     local ret=0 out="" labels="" dev="" label="" ftype="" isodevs="" uuids=""
- out=$(blkid -c /dev/null -o export) || {
+ out=$(/sbin/blkid -c /dev/null -o export) || {
         ret=$?
         error "failed running [$ret]: blkid -c /dev/null -o export"
         DI_FS_LABELS="$UNAVAILABLE:error"

Of course with UsrMerge you could also use /usr/sbin/blkid.

As stated in upstream bug report I have not the slightest idea what it calling ds-identify during boot. I thought it would be the systemd cloud-init generator, but I added debug output to it and it apparently is not called. For all the gory details see the upstream bug report.

Proper fix might be to make sure blkid is in $PATH.