Get missing nodes:
[anoopkumar@a-d-docucp01 ~]$ sdiff -s <(!!) <(docker node ls | grep -Eiv 'HOSTNAME|a-d-docucp01|DOCWWN0' | awk '{ print $2 }' | sort)
sdiff -s <(for i in {2..18} ; do ssh a$i hostname ; done | sort) <(docker node ls | grep -Eiv 'HOSTNAME|a-d-docucp01|DOCWWN0' | awk '{ print $2 }' | sort)
a-d-docwn01 <
a-d-docwn02 <
a-d-docwn03 <
a-d-docwn05 <
a-d-docwn08 <