CHR: Installing on KVM

CHR: Installing on KVM

This guide covers deploying RouterOS Cloud Hosted Router (CHR) on KVM/QEMU using the RAW disk image. KVM is the recommended hypervisor for Linux hosts and provides the best performance via Virtio paravirtualized drivers.

Prerequisites

• Linux host with KVM support (grep -E 'vmx|svm' /proc/cpuinfo must return output)
• qemu-kvm, libvirt, and virt-manager or virsh installed
• At least 256MB RAM and 128MB disk available for the CHR VM
• Root or libvirt group membership

Download the CHR Image

1. Visit the MikroTik download page
2. Select the Cloud Hosted Router section
3. Download the RAW disk image (.img file) for your desired RouterOS version

# Example: download and decompress CHR image
wget https://download.mikrotik.com/routeros/7.x/chr-7.x.img.zip
unzip chr-7.x.img.zip

Move the image to a libvirt storage pool:

sudo mv chr-7.x.img /var/lib/libvirt/images/chr.img

Create the Virtual Machine

Using virt-install (CLI)

sudo virt-install \
  --name chr \
  --memory 1024 \
  --vcpus 2 \
  --disk /var/lib/libvirt/images/chr.img,format=raw,bus=virtio \
  --network network=default,model=virtio \
  --os-variant linux2022 \
  --import \
  --noautoconsole

Key parameters:

Parameter	Value	Reason
--disk bus=virtio	virtio	Best performance; CHR supports Virtio disk
--network model=virtio	virtio	Best performance; enables Fast Path in v7
--import	—	Uses existing disk image, no ISO installer
--os-variant linux2022	linux	Closest match for CHR guest type

Using virt-manager (GUI)

1. Open Virtual Machine Manager
2. Click File → New Virtual Machine
3. Select Import existing disk image
4. Browse to the .img file
5. Set OS type to Generic Linux
6. Allocate RAM (1024MB recommended) and CPU count
7. Before finishing, check Customize configuration before install
8. In NIC settings, change model to virtio
9. In Disk settings, verify bus is VirtIO
10. Click Begin Installation

Network Interface Configuration

For multiple network interfaces, add additional NICs using virsh after VM creation:

# Add a second virtio NIC to the default network
sudo virsh attach-interface chr --type network --source default \
  --model virtio --config --live

Inside RouterOS, interfaces appear as etherN in order of MAC address:

/interface print

Initial Login and Configuration

Connect to the VM console:

sudo virsh console chr

Log in with the default credentials:

Username: admin
Password: (empty — press Enter)

Perform initial configuration:

# Set admin password
/user set admin password=StrongPassword123!

# Assign IP address to first interface
/ip address add address=192.168.88.1/24 interface=ether1

# Add default route
/ip route add dst-address=0.0.0.0/0 gateway=192.168.88.254

# Set DNS servers
/ip dns set servers=1.1.1.1,8.8.8.8

# Enable SSH
/ip service enable ssh

KVM Guest Agent

CHR supports the QEMU guest agent for host-guest integration on KVM:

# Add virtio-serial device and guest agent channel when creating the VM
sudo virt-install \
  --name chr \
  --memory 1024 \
  --vcpus 2 \
  --disk /var/lib/libvirt/images/chr.img,format=raw,bus=virtio \
  --network network=default,model=virtio \
  --channel unix,target_type=virtio,name=org.qemu.guest_agent.0 \
  --os-variant linux2022 \
  --import \
  --noautoconsole

With the guest agent active, the host can:

• Execute scripts inside the guest: virsh qemu-agent-command chr '{"execute":"guest-exec",...}'
• Transfer files: guest-file-open, guest-file-write, guest-file-close
• Retrieve network interface info: guest-network-get-interfaces

Performance Optimization

Tip

Always use Virtio for both disk and network interfaces. RouterOS v7 supports Fast Path with virtio-net, providing significantly higher throughput than E1000.

For production deployments:

# Use multiple vCPUs for higher interface counts
# RAM formula: 256 + [8 × CPU_COUNT × (INTERFACE_COUNT - 1)] MB
# Example: 2 CPUs, 4 interfaces → 256 + [8 × 2 × 3] = 304MB minimum

VLAN Configuration on Linux Bridge

If using Linux bridge (virbr0 or custom bridge), ensure VLAN pass-through is enabled:

# Disable IGMP snooping if IPv6 multicast issues occur
echo -n 0 > /sys/class/net/virbr0/bridge/multicast_snooping

In RouterOS, configure bridge VLAN filtering for trunk interfaces:

/interface bridge add name=br1 vlan-filtering=yes
/interface bridge port add bridge=br1 interface=ether1
/interface bridge vlan add bridge=br1 vlan-ids=10,20 tagged=br1,ether1

Troubleshooting

VM Does Not Start

Verify KVM is available:

sudo kvm-ok
# Should output: KVM acceleration can be used

Check for CPU virtualization support:

grep -E 'vmx|svm' /proc/cpuinfo | head -1

No Network Connectivity

Verify the libvirt default network is active:

sudo virsh net-list --all
sudo virsh net-start default
sudo virsh net-autostart default

Slow Disk or Network Performance

Check interface driver inside RouterOS:

/interface ethernet print detail

If the driver shows e1000 instead of virtio, shut down the VM and change the NIC model in virt-manager or using virsh edit chr.

Related Topics

• Cloud Hosted Router, CHR
• CHR Licensing
• CHR: Installing on VirtualBox