NgTech-LTD/gns3-server
2
0
Fork 0
mirror of https://github.com/GNS3/gns3-server.git synced 2026-08-27 12:30:13 +03:00
Code Issues Packages Projects Releases Wiki Activity

docs: add troubleshooting for controller hostname unreachable

Browse Source 
Add documentation for the "No common subnet" error when the
controller's hostname in /etc/hosts resolves to an unreachable
or stale IP address.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
YueGuobin 2026-04-25 15:44:20 +08:00
parent 517764a7ac
commit f9d1ccc701
No known key found for this signature in database
1 changed files with 20 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
docs/features/compute-controller-setup.md
View File

@ -102,3 +102,23 @@ POST /v3/computes
1. Verify Controller's `host` is set to its actual IP, not `0.0.0.0`
2. Ensure both machines are on the same network
3. Check firewall rules allow UDP communication
### Controller Hostname Unreachable
If the controller machine uses a hostname defined in `/etc/hosts` (e.g., `guobin.localhost`), and the compute node reports:
```
Cannot get an IP address on same subnet: No common subnet for compute X (controller) and Y
```
1. **Symptom**: The controller's hostname resolves to an IP that is unreachable from the compute node
2. **Root Cause**: The `/etc/hosts` entry for the controller's hostname points to a stale or unreachable IP address
3. **Solution**:
- Ensure the controller's hostname in `/etc/hosts` resolves to the correct, reachable IP address
- Example (correct):
```
192.168.1.104 guobin.localhost
```
- If the machine's IP is dynamic (DHCP), consider:
- Setting a DHCP static lease on the router for a fixed IP
- Using mDNS (`.local` domain) if supported by the compute node