Unable to create Central Inventory
But the central inventory location should be /u01/app/oracle/oraInventory, not what you have. It is much better to follow the recommandations of Oracle for directories naming (see OFA section in installation guide).

check what is the id and the group of the user running the runInstaller, usually it is oracle:oinstall

then as user root

mkdir -p /u01/app/oracle
chown -R oracle:oinstall /u01/app/oracle (assuming oracle:oinstall)


before starting runInstaller make sure you don't have the env variable ORACLE_HOME set. You don't need to set ORACLE_BASE, but if you do then it should be pointing to /u01/app/oracle. So

export ORACLE_BASE=/u01/app/oracle


If the env variable ORACLE_BASE is not set, Oracle is clever enough to recognize /u01/app/oracle as the standard ORACLE_BASE location

Note: as a side note, standardize the id of user oracle and the gid of groups oinstall and dba accross all your system, i.e use the same values everywhere.