Running and Verification

Determine the number of running processes based on the server configuration.
If multiple nodes are running, configure the network environment:
- In the /etc/hosts file, add the IP addresses and host names of the servers.
- Enable password-free SSH login between the servers.
- Disable the firewall and ensure that clients and servers are not disconnected.

Procedure

Use PuTTY to log in to the server as the root user.
Download the WRF test case conus12km.
https://www2.mmm.ucar.edu/wrf/src/conus12km.tar.gz
Upload conus12km.tar.gz to the /path/to/conus12km directory.
Decompress the installation package.
```
tar -vxf conus12km.tar.gz
```
Copy the binary file to the working directory and then go to the working directory.
```
cp -r /path/to/WRF/WRF-4.2/run/* conus12km
cd conus12km
ln -sf /path/to/WRF/WRF-4.2/main/*.exe ./
```
When the system asks you whether to overwrite the original file, enter no.
Start the WRF program.
```
time mpirun --allow-run-as-root -np 8 ./wrf.exe
```
Check the real value (unit: s). A smaller value indicates higher performance.

The -np parameter indicates the total number of used processes.
Check whether the program stops properly.
```
less rsl.out.0000
```
If the following information is displayed at the end of rsl.out.0000, the program is successfully executed and stops properly.
The environment variable configuration for multiple nodes is the same as that for a single node. Configure the hostfile file in the working directory.
1. Open the hostfile file.
```
vi hostfile
```
2. Press i to enter the edit mode and configure the name of each node in the hostfile file.
```
node1
node2
```
  Set them based on the actual node names (host names).
3. Press Esc, type :wq!, and press Enter to save the file and exit.
4. Start the running.
```
time mpirun --allow-run-as-root -np 16 -N 8 -hostfile hostfile ./wrf.exe
```
  The -N parameter indicates the number of processes running on each server.

Parent topic: WRF 4.2 Porting Guide (openEuler 21.03)