medusa/the_information_nexus
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Update tech_docs/virtualization/proxmox_dhcp.md

Browse Source
This commit is contained in:
medusa
2025-06-30 09:02:28 +00:00
parent b3d3dd69e0
commit 5e2da39599
1 changed files with 98 additions and 58 deletions
Download Patch File Download Diff File Expand all files Collapse all files

150
tech_docs/virtualization/proxmox_dhcp.md
View File

@@ -1,73 +1,113 @@
For your standalone Proxmox setup, switching between static and dynamic IP configurations and managing virtual bridges are important tasks. Below, I'll provide a concise guide to handle these changes effectively and safely.
**Prerequisites:**
* You have SSH access to your Proxmox host.
* You have `sudo` privileges or are logged in as root.
* You know the name of your physical network interface connected to `vmbr0` (e.g., `enp3s0`, `eth0`). You can find this using `ip a`.
---
### Switching from Static IP to DHCP:
- **Backup Configurations:** Always backup configuration files before making changes (`cp /etc/network/interfaces /etc/network/interfaces.bak`).
**Caution:** Changing network configurations can disrupt connectivity. Ensure you have a way to regain access (e.g., direct console access) if something goes wrong.
```bash
cp /etc/network/interfaces /etc/network/interfaces.bak
```
1. **Backup Configurations:**
Always backup configuration files before making changes. This allows for easy rollback if needed.
```bash
cp /etc/network/interfaces /etc/network/interfaces.bak
```
**Update Network Interface Configuration:**
Open `/etc/network/interfaces` in a text editor:
```bash
vim /etc/network/interfaces
```
- Change the `vmbr0` configuration from static to DHCP:
```bash
auto vmbr0
iface vmbr0 inet dhcp
bridge-ports enp3s0
bridge-stp off
bridge-fd 0
```
- Save the changes and exit the editor.
- **Restart Networking to Apply Changes:**
- Apply the new network settings:
```bash
systemctl restart networking
```
- **Find the New DHCP-Assigned IP Address:**
- After the network restarts, check the assigned IP:
```bash
ip addr show vmbr0
```
- **Update `/etc/hosts` with the New IP:**
- Edit the `/etc/hosts` file to replace the old static IP with the new one:
```bash
nano /etc/hosts
```
- Modify the line with the old IP to the new one you just obtained:
```plaintext
192.168.86.62 whitebox.foxtrot.lan whitebox # Old IP
192.168.x.x whitebox.foxtrot.lan whitebox # New DHCP IP
```
- Save and exit.
### Creating a New Virtual Bridge (`vmbrX`):
- **Add a New Virtual Bridge Configuration:**
- Edit `/etc/network/interfaces`:
2. **Update Network Interface Configuration:**
Open `/etc/network/interfaces` in your preferred text editor (e.g., `vim` or `nano`):
```bash
vim /etc/network/interfaces
```
- Add a new bridge configuration at the end of the file:
```bash
auto vmbrX # Replace X with the next available number
iface vmbrX inet manual
bridge-ports none
Locate the `vmbr0` configuration block and change it from static to DHCP. **Replace `<YOUR_PHYSICAL_NIC_HERE>` with your actual physical network interface name (e.g., `enp3s0`, `eth0`).**
**Before (Example Static):**
```
auto vmbr0
iface vmbr0 inet static
address 192.168.86.62/24
gateway 192.168.86.1
bridge-ports enp3s0
bridge-stp off
bridge-fd 0
```
- Save and exit the editor.
- **Activate the New Bridge:**
- Restart the networking service to bring up the new bridge:
**After (Example DHCP):**
```
auto vmbr0
iface vmbr0 inet dhcp
bridge-ports <YOUR_PHYSICAL_NIC_HERE>
bridge-stp off
bridge-fd 0
```
Save the changes and exit the editor.
3. **Restart Networking to Apply Changes:**
Apply the new network settings. This will temporarily disrupt network connectivity.
```bash
systemctl restart networking
```
4. **Find the New DHCP-Assigned IP Address:**
After the network restarts, check the assigned IP address for `vmbr0`:
```bash
ip a show vmbr0
```
Note down the new IP address.
5. **Update `/etc/hosts` with the New IP:**
Edit the `/etc/hosts` file to replace the old static IP with the new DHCP-assigned one. This is crucial for services and SSH access that rely on hostname resolution.
```bash
nano /etc/hosts
```
Find the line containing your Proxmox host's old IP and hostname (e.g., `192.168.86.62 whitebox.foxtrot.lan whitebox`) and **replace** the old IP address with the new one you just obtained.
**Example:**
```plaintext
# Before (your line will vary):
# 192.168.86.62 whitebox.foxtrot.lan whitebox
# After (replace the old IP with your new DHCP IP):
192.168.X.Y whitebox.foxtrot.lan whitebox
```
Save and exit.
---
### Creating a New Virtual Bridge (`vmbrX`):
This process creates an isolated virtual bridge, typically used for internal VM communication, not directly connected to a physical network interface.
1. **Add a New Virtual Bridge Configuration:**
Edit `/etc/network/interfaces`:
```bash
vim /etc/network/interfaces
```
Add a new bridge configuration at the end of the file. To find the next available number for `vmbrX`, check existing `vmbr` entries in this file (e.g., if you have `vmbr0` and `vmbr1`, use `vmbr2`).
```bash
auto vmbrX # Replace X with the next available number (e.g., vmbr1, vmbr2)
iface vmbrX inet manual
bridge-ports none # 'none' indicates it's not bound to a physical port
bridge-stp off
bridge-fd 0
```
Save and exit the editor.
2. **Activate the New Bridge:**
Restart the networking service to bring up the new bridge.
```bash
systemctl restart networking
```
You can verify the bridge creation with `ip a show vmbrX` or `brctl show`.
---
### General Notes:
* **Validation:** After any network changes, always verify connectivity and functionality of your Proxmox host and virtual machines.
* **Reverting Changes:** If you encounter issues, you can revert your `/etc/network/interfaces` file by copying the backup: `cp /etc/network/interfaces.bak /etc/network/interfaces` and then restarting the networking service.
* **Console Access:** For critical network changes, having direct console access (physical keyboard/monitor or iLO/iDRAC/IPMI) is highly recommended as a fallback.