code
---
    frames = [hosts_df, memory_df]
    newframe=pd.concat([frames)
    print(f"\n***{newframe}***")

output
---
***                 Name     PrivateIP      Memory
0          bastion001  10.238.2.166         NaN
1     logicmonitor001   10.238.2.52         NaN
2     logicmonitor002   10.238.2.53         NaN
..                ...           ...         ...
0                 NaN           NaN   7904680.0
0                 NaN           NaN   7904672.0
0                 NaN           NaN   7904680.0


[75 rows x 3 columns]***