New OS available: Proxmox Virtual Environment (VE) 9

Bare Metal and VPS
1

Hi everyone,
We have just added a new OS to the bare metal catalog: Proxmox Virtual VE 9, based on Debian 13 (Trixie). This is the first Proxmox version for which we enable ZFS by default for the data partition.

Please refer to the publisher's release notes for further information.

2

Thanks @le_sbraz for the information

3

Thanks @le_sbraz . I waited this news to deploy my new servers.

4

As setting up Proxmox 9 to work on a Kimsufi server with a single external IP address was a bit of a nightmare, we wrote this cookbook.

Hope it helps

Walter


OVH/Kimsufi Proxmox Container Setup Guide

From Bare Metal to Working Web Server

Tested on: KS-5 server, Proxmox 9, September 2025

Overview

This guide documents the complete process of setting up working container networking on OVH/Kimsufi dedicated servers with Proxmox 9, from initial server provisioning to a functioning web server accessible from the internet.

Prerequisites

  • OVH/Kimsufi dedicated server
  • Proxmox 9 installed by OVH
  • SSH access to the server
  • Basic understanding of Linux networking

OVH/Kimsufi Proxmox 9 Container Setup Guide

From Bare Metal to Working Web Server

Tested on: KS-5 server, Proxmox 9, September 2025

Overview

This guide documents the complete process of setting up working container networking on OVH/Kimsufi dedicated servers with Proxmox, from initial server provisioning to a functioning web server accessible from the internet.

Prerequisites

  • OVH/Kimsufi dedicated server
  • Proxmox 9 installed by OVH
  • SSH access to the server
  • Basic understanding of Linux networking

Part 1: Initial Server Setup

1.1 Access and User Setup

# SSH into server as root
ssh root@YOUR_SERVER_IP

Create admin user


adduser clubadmin

usermod -aG sudo clubadmin


Set up SSH key access


mkdir -p /home/clubadmin/.ssh

cp /root/.ssh/authorized_keys /home/clubadmin/.ssh/

chown -R clubadmin:clubadmin /home/clubadmin/.ssh

chmod 700 /home/clubadmin/.ssh

chmod 600 /home/clubadmin/.ssh/authorized_keys


Configure passwordless sudo


echo "clubadmin ALL=(ALL) NOPASSWD:ALL" > /etc/sudoers.d/clubadmin

chmod 440 /etc/sudoers.d/clubadmin

1.2 Proxmox Web Interface Access

Set password for root to access Proxmox web interface:

passwd root

Access Proxmox at: https://YOUR_SERVER_IP:8006

Part 2: Container Network Configuration

2.1 The Problem

Default Proxmox container networking on OVH fails because:

  • Containers connect directly to external bridge (vmbr0)
  • No NAT configuration for container traffic
  • Missing FORWARD rules between internal and external networks

2.2 Create Internal Bridge Network

Edit /etc/network/interfaces and add:

auto vmbr6
iface vmbr6 inet static
    address 10.0.0.254/24
    bridge-ports none
    bridge-stp off
    bridge-fd 0
    post-up echo 1 > /proc/sys/net/ipv4/ip_forward
    post-up iptables -t nat -A POSTROUTING -s 10.0.0.0/24 -o vmbr0 -j MASQUERADE
    post-down iptables -t nat -D POSTROUTING -s 10.0.0.0/24 -o vmbr0 -j MASQUERADE

2.3 Activate Internal Bridge

# Bring up the new bridge
ifup vmbr6

Verify bridge creation


ip addr show vmbr6

2.4 Configure Packet Forwarding

# Enable IP forwarding permanently
echo 'net.ipv4.ip_forward = 1' >> /etc/sysctl.conf
sysctl -p

Add FORWARD rules for container-to-internet traffic


iptables -I FORWARD -i vmbr6 -o vmbr0 -j ACCEPT

iptables -I FORWARD -i vmbr0 -o vmbr6 -m state --state RELATED,ESTABLISHED -j ACCEPT


Save iptables rules


mkdir -p /etc/iptables

iptables-save > /etc/iptables/rules.v4

Part 3: Container Creation

3.1 Download Container Template

In Proxmox web interface:

  1. Navigate to node → local storage
  2. Click "CT Templates" tab
  3. Click "Templates" button
  4. Download "ubuntu-22.04-standard"

3.2 Create Container via Web Interface

  1. Right-click node name → "Create CT"
  2. General tab:
    • CT ID: 100
    • Hostname: your-container-name
    • Set password
    • Add SSH public key
  3. Template tab:
    • Select ubuntu-22.04-standard
  4. Root Disk tab:
    • Size: 8GB (adjust as needed)
  5. CPU/Memory tabs:
    • Set as needed (1 core, 1GB RAM for basic web server)
  6. Network tab:
    • CRITICAL: Change bridge from vmbr0 to vmbr6
    • Set static IP: 10.0.0.100/24 (increment for additional containers)
    • Gateway: 10.0.0.254
  7. DNS tab:
    • Use host settings

3.3 Container Network Verification

# Start container
pct start 100

Enter container


pct enter 100


Test connectivity


ping -c 3 10.0.0.254    # Gateway

ping -c 3 8.8.8.8       # Internet

wget --timeout=10 http://github.com  # HTTP connectivity

Part 4: Web Server Setup

4.1 Install Caddy in Container

# Download and install Caddy
wget -O /tmp/caddy.tar.gz 'https://github.com/caddyserver/caddy/releases/download/v2.7.6/caddy_2.7.6_linux_amd64.tar.gz'
tar -xzf /tmp/caddy.tar.gz -C /usr/local/bin/ caddy
chmod +x /usr/local/bin/caddy

Verify installation


/usr/local/bin/caddy version

4.2 Configure Web Server

# Create directory structure
mkdir -p /etc/caddy /var/www/html

Create test page


echo '<h1>Working Web Server</h1><p>Container networking successful!</p>' > /var/www/html/index.html


Create basic Caddyfile


echo ':8080 {

root * /var/www/html

file_server

}' > /etc/caddy/Caddyfile


Start Caddy


nohup /usr/local/bin/caddy run --config /etc/caddy/Caddyfile > /var/log/caddy.log 2>&1 &

Part 5: External Access Configuration

5.1 Port Forwarding Setup

# Exit container
exit

Add port forwarding (external port 8080 → container port 8080)


iptables -t nat -A PREROUTING -p tcp --dport 8080 -j DNAT --to-destination 10.0.0.100:8080

iptables -A FORWARD -p tcp -d 10.0.0.100 --dport 8080 -j ACCEPT


Save rules


iptables-save > /etc/iptables/rules.v4

5.2 Test External Access

From external machine:

curl http://YOUR_SERVER_IP:8080

Part 6: Multiple Container Setup

6.1 Additional Containers

For each new container:

  1. Use Proxmox web interface
  2. Network: Bridge vmbr6, increment IP (10.0.0.101, 10.0.0.102, etc.)
  3. Gateway: 10.0.0.254
  4. Add port forwarding rules as needed

6.2 Port Forwarding for Additional Services

# Example: Forward port 8081 to second container
iptables -t nat -A PREROUTING -p tcp --dport 8081 -j DNAT --to-destination 10.0.0.101:80
iptables -A FORWARD -p tcp -d 10.0.0.101 --dport 80 -j ACCEPT

Conclusion

This configuration provides stable container networking on OVH infrastructure. The key insight is that containers need an internal bridge network with proper NAT and forwarding rules, rather than connecting directly to the external bridge.

After implementing this setup, containers have full internet connectivity and can be accessed from external networks through port forwarding rules. This solution eliminates the TCP connectivity issues that can occur with incorrect container networking configurations.