If we are getting below error when try to bring up ens192 interface in redhat 8 system, then you need to follow the below standard process to resolve this issue.
[root@localhost~]# ifup ens192
Error: unknown connection '/etc/sysconfig/network-scripts/ifcfg-ens192'.
To resolve this issue, please follow the two approach.
1. Remove NM_CONTROLLED=no option from ifcfg-ensX file.
2. Install network-scripts rpm package to use the legacy ifup command in redhat 8.
Hope, above solution will resolve your issue.
