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Metal3 Bare-Metal Worker Nodes

This guide covers a qualified bare-metal worker workflow for the Kube-DC management cluster using Metal3, Bare Metal Operator, Ironic, and Cluster API Provider Metal3. The workflow controls power and can erase or reprovision enrolled hosts. Validate hardware support, network reachability, image compatibility, and rollback in a non-production pool first.

Architecture

Metal3 bare-metal worker topologyThe Kube-DC management cluster has three RKE2 control-plane servers with OVN database replicas. Metal3 control-plane components include Bare Metal Operator managing BareMetalHost resources, Ironic providing PXE or virtual-media provisioning, CAPM3, and Metal3 IPAM. These components reach server BMCs using IPMI, Redfish, iDRAC, or iLO and provision a pool of RKE2 worker nodes that can run KubeVirt. Management, optional provider, provisioning, and BMC networks remain distinct.KUBE-DC MANAGEMENT CLUSTERControl-plane serversmaster-1 · master-2master-3 · RKE2 + OVN DBCAPM3 controlCluster API Provider Metal3 + IPAMBare Metal OperatorBareMetalHost CRspower + inspectionIronicPXE / virtual mediaimage provisioningBMC pathIPMI · RedfishiDRAC · iLOBARE-METAL WORKER POOLProvisioned workersworker-1 · worker-2 · worker-3 · worker-NRKE2 agents · KubeVirt eligible
Three existing RKE2 servers host the management control plane; Metal3 controllers use BMC and provisioning networks to inspect, provision, join, and remediate the separate bare-metal worker pool.

How It Works

  1. Enroll — Register each bare-metal server as a BareMetalHost (BMH) CR with its BMC address and credentials
  2. Inspect — Ironic powers on the server via BMC, PXE-boots a ramdisk, and collects hardware inventory (CPUs, RAM, disks, NICs, MAC addresses)
  3. Provision — When a MachineDeployment scales up, CAPM3 selects an available BMH, writes an OS image to disk via Ironic, and injects cloud-init user/network data
  4. Join — The provisioned server boots into Ubuntu with RKE2 agent pre-configured, joins the management cluster, and becomes a schedulable worker node
  5. HealMachineHealthCheck monitors node health; if a node becomes unhealthy, the Metal3 remediation controller power-cycles it via BMC or reprovisions it

Prerequisites

Hardware Requirements

RequirementDetails
BMC accessEach worker server must have a Baseboard Management Controller (IPMI, Redfish, iDRAC, iLO) reachable from the management cluster
PXE or Virtual Media bootServers must support network boot (PXE) or Redfish Virtual Media for OS provisioning
Boot modeUEFI recommended (legacy BIOS supported but not recommended)
Network interfacesInterfaces required by the selected management and provider-network topology; a trunk is needed only when that topology carries VLANs
StorageAt least one disk for OS installation (SSD recommended, 100 GB+)

Network Requirements

The management cluster nodes must be able to reach:

TargetProtocolPortPurpose
Worker BMCsIPMI/Redfish623 (IPMI), 443 (Redfish)Power management, virtual media
Worker PXE NICsDHCP + TFTP67-69, 6180PXE boot (if not using virtual media)
Worker management NICsSSH22Post-provisioning verification

Workers need management-cluster connectivity and every provider network used by workloads scheduled on them. They do not require an unused public or cloud VLAN merely because a control-plane node has it. Match Kube-OVN ProviderNetwork node selection and interface configuration to the actual cabling. See the network model.

Software Requirements

ComponentStatusNotes
Kube-DC management clusterRequiredCompatible installed cluster; three server nodes are the reference HA profile in the Installation Guide
cert-managerAlready installedDeployed by the kube-dc installer (Flux)
Cluster API coreAlready installedDeployed by the kube-dc installer (Flux)
CAPM3 + BMO + IronicTo be installedThis guide covers installation
OS disk imageTo be preparedUbuntu 24.04 with RKE2 agent pre-baked

Information to Collect

Before proceeding, gather the following for each worker server:

InfoExampleHow to obtain
BMC IP address192.168.1.101Check BMC/iDRAC web UI or server documentation
BMC protocolredfish-virtualmediaDepends on hardware vendor (see supported hardware)
BMC credentialsadmin / passwordSet via BMC web interface
Boot NIC MAC addressaa:bb:cc:dd:ee:01Check ip link output or BMC hardware inventory
Management NIC nameeth0 or eno1Varies by hardware; inspect after first boot
Trunk NIC nameeth1 or enp94s0f0np0The VLAN-capable NIC connected to cloud/provider switch

Phase 1 — Install Metal3 Components

1.1 Initialize CAPM3

The Kube-DC installer already deploys Cluster API core components. Add the Metal3 infrastructure provider and IPAM:

clusterctl init --infrastructure metal3 --ipam metal3

This installs:

  • CAPM3 — Cluster API Provider Metal3 (manages Metal3Machine, Metal3MachineTemplate)
  • Metal3 IPAM — IP address management for static IP assignment during provisioning
  • Bare Metal Operator (BMO) — Manages BareMetalHost lifecycle

1.2 Deploy Ironic

Ironic is the provisioning engine that Metal3 uses to interact with hardware via BMC protocols. Deploy it using the Ironic Standalone Operator:

# Install Ironic Standalone Operator
kubectl apply -k https://github.com/metal3-io/ironic-standalone-operator/config/default

kubectl -n ironic-standalone-operator-system wait \
--for=condition=Available --timeout=300s \
deploy/ironic-standalone-operator-controller-manager

Create the Ironic deployment. Adjust the network settings to match your BMC network:

# ironic.yaml
apiVersion: metal3.io/v1alpha1
kind: Ironic
metadata:
name: ironic
namespace: baremetal-operator-system
spec:
networking:
interface: eth0 # Management interface on master nodes
ipAddress: 192.168.0.1 # Management IP of the node running Ironic
dhcp:
networkCIDR: 192.168.0.0/18 # Management network CIDR
rangeBegin: 192.168.10.1 # DHCP range for PXE boot (avoid conflicts)
rangeEnd: 192.168.10.254
databaseRef:
name: ironic-mariadb
namespace: baremetal-operator-system
kubectl create ns baremetal-operator-system
kubectl apply -f ironic.yaml
PXE vs Virtual Media

If your qualified hardware supports Redfish Virtual Media, you can skip the PXE DHCP configuration. Virtual Media mounts the boot ISO directly via BMC, avoiding PXE network complexity. Use BMC addresses like redfish-virtualmedia://192.168.1.101/redfish/v1/Systems/1 in your BareMetalHost specs.

1.3 Verify Metal3 Stack

# Check all Metal3 components are running
kubectl get pods -n capm3-system
kubectl get pods -n baremetal-operator-system
kubectl get pods -n ironic-standalone-operator-system

# Verify CRDs are installed
kubectl api-resources | grep metal3
# Expected: baremetalhosts, metal3machines, metal3machinetemplates, etc.

Phase 2 — Prepare the Worker OS Image

Metal3 provisions servers by writing a disk image. This image must contain:

  • Ubuntu 24.04 LTS base system
  • RKE2 agent binaries (pre-installed but not started)
  • cloud-init for first-boot configuration (network, hostname, cluster join)
  • Kernel modules required by Kube-OVN (openvswitch, nf_conntrack)

2.1 Build the Image

Use a tool like image-builder or create a custom image with Packer:

# Example: Download base Ubuntu 24.04 cloud image and customize
wget https://cloud-images.ubuntu.com/noble/current/noble-server-cloudimg-amd64.img

# Customize with virt-customize (libguestfs)
virt-customize -a noble-server-cloudimg-amd64.img \
--install curl,iptables,linux-headers-generic,nfs-common,open-iscsi \
--run-command 'curl -sfL https://get.rke2.io | INSTALL_RKE2_VERSION=v1.36.3+rke2r1 INSTALL_RKE2_TYPE=agent sh -' \
--run-command 'systemctl enable rke2-agent.service' \
--run-command 'echo nf_conntrack >> /etc/modules' \
--run-command 'echo "fs.inotify.max_user_watches=1524288" >> /etc/sysctl.conf' \
--run-command 'echo "fs.inotify.max_user_instances=4024" >> /etc/sysctl.conf' \
--run-command 'echo "net.ipv4.ip_forward=1" >> /etc/sysctl.conf' \
--run-command 'systemctl disable systemd-resolved' \
--run-command 'rm -f /etc/resolv.conf && echo -e "nameserver 8.8.8.8\nnameserver 8.8.4.4" > /etc/resolv.conf'

2.2 Host the Image

Make the image available via HTTP from a server reachable by Ironic:

# Compute checksum
sha256sum noble-server-cloudimg-amd64.img > noble-server-cloudimg-amd64.img.sha256sum

# Serve via nginx, Apache, or any HTTP server
# Example URL: http://192.168.0.1:8080/images/noble-server-cloudimg-amd64.img

Phase 3 — Enroll Bare-Metal Hosts

3.1 Create BMC Credentials

Create a Kubernetes secret for each worker server's BMC credentials:

# bmh-secrets.yaml
apiVersion: v1
kind: Secret
metadata:
name: worker-1-bmc
namespace: baremetal-operator-system
type: Opaque
stringData:
username: admin
password: your-bmc-password
---
apiVersion: v1
kind: Secret
metadata:
name: worker-2-bmc
namespace: baremetal-operator-system
type: Opaque
stringData:
username: admin
password: your-bmc-password
kubectl apply -f bmh-secrets.yaml

3.2 Create BareMetalHost Resources

Register each server with its BMC address, boot MAC, and boot mode:

# baremetalhosts.yaml
apiVersion: metal3.io/v1alpha1
kind: BareMetalHost
metadata:
name: worker-1
namespace: baremetal-operator-system
spec:
online: true
bootMACAddress: "aa:bb:cc:dd:ee:01" # MAC of the PXE/management NIC
bootMode: UEFI
bmc:
address: redfish-virtualmedia://192.168.1.101/redfish/v1/Systems/1
credentialsName: worker-1-bmc
disableCertificateVerification: true
automatedCleaningMode: metadata # Clean disk metadata between provisions
rootDeviceHints:
minSizeGigabytes: 100 # Select disk ≥100 GB for OS install
---
apiVersion: metal3.io/v1alpha1
kind: BareMetalHost
metadata:
name: worker-2
namespace: baremetal-operator-system
spec:
online: true
bootMACAddress: "aa:bb:cc:dd:ee:02"
bootMode: UEFI
bmc:
address: redfish-virtualmedia://192.168.1.102/redfish/v1/Systems/1
credentialsName: worker-2-bmc
disableCertificateVerification: true
automatedCleaningMode: metadata
rootDeviceHints:
minSizeGigabytes: 100
kubectl apply -f baremetalhosts.yaml

3.3 Wait for Inspection

Watch the BMH resources progress through registeringinspectingavailable:

kubectl get bmh -n baremetal-operator-system -w

# NAME STATE CONSUMER ONLINE ERROR AGE
# worker-1 registering true 10s
# worker-1 inspecting true 30s
# worker-1 available true 5m
# worker-2 available true 5m

Once a BMH reaches available, Ironic has successfully:

  • Powered on the server via BMC
  • PXE-booted a ramdisk
  • Collected hardware inventory (CPUs, RAM, disks, NICs with MAC addresses)
  • Powered the server back off

Inspect the discovered hardware:

kubectl get bmh worker-1 -n baremetal-operator-system -o jsonpath='{.status.hardware}' | jq .

This shows all discovered NICs, disks, CPU, and RAM — essential for configuring network data templates.


Phase 4 — Configure CAPI Resources for Worker Provisioning

4.1 Create Metal3 IPAM Pool

Define an IP pool for worker management network addresses:

# ippool-mgmt.yaml
apiVersion: ipam.metal3.io/v1alpha1
kind: IPPool
metadata:
name: worker-mgmt-pool
namespace: baremetal-operator-system
spec:
clusterName: kube-dc-mgmt
namePrefix: worker-mgmt
pools:
- start: 192.168.0.50
end: 192.168.0.99
prefix: 18
gateway: 192.168.0.254
kubectl apply -f ippool-mgmt.yaml

4.2 Create Metal3DataTemplate

The Metal3DataTemplate defines how network data and metadata are generated for each provisioned worker. This is critical — it tells cloud-init how to configure the server's network interfaces.

# metal3datatemplate.yaml
apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: Metal3DataTemplate
metadata:
name: worker-data-template
namespace: baremetal-operator-system
spec:
clusterName: kube-dc-mgmt
metaData:
strings:
- key: local-hostname
value: "{{ ds.meta_data.name }}"
networkData:
links:
ethernets:
# Management NIC — carries Kubernetes API, SSH, node-to-node traffic
- id: mgmt-nic
macAddress:
fromHostInterface: eth0 # Matched against BMH hardware inventory
type: phy
mtu: 1500
# Trunk NIC — carries cloud and provider VLANs
# Do NOT assign an IP; Kube-OVN manages this via OVS bridges
- id: trunk-nic
macAddress:
fromHostInterface: eth1 # Matched against BMH hardware inventory
type: phy
mtu: 9000
networks:
ipv4:
- id: mgmt-network
ipAddressFromIPPool: worker-mgmt-pool
link: mgmt-nic
routes:
- network: 0.0.0.0
prefix: 0
gateway:
fromIPPool: worker-mgmt-pool
services:
dns:
- 8.8.8.8
- 8.8.4.4
kubectl apply -f metal3datatemplate.yaml
NIC Name Matching

The fromHostInterface values (eth0, eth1) must match the NIC names discovered during BMH inspection. Check kubectl get bmh worker-1 -o jsonpath='{.status.hardware.nics}' to see the actual interface names on your hardware. If NICs have different names across servers, use MAC-based matching or ensure consistent naming via udev rules in the OS image.

4.3 Create Metal3MachineTemplate

# metal3machinetemplate.yaml
apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: Metal3MachineTemplate
metadata:
name: worker-machine-template
namespace: baremetal-operator-system
spec:
template:
spec:
image:
url: http://192.168.0.1:8080/images/noble-server-cloudimg-amd64.img
checksum: http://192.168.0.1:8080/images/noble-server-cloudimg-amd64.img.sha256sum
checksumType: sha256
format: qcow2
dataTemplate:
name: worker-data-template
hostSelector: {} # Selects any available BMH (or use matchLabels)
kubectl apply -f metal3machinetemplate.yaml

4.4 Create Cloud-Init UserData

The cloud-init user data configures RKE2 agent to join the management cluster and applies required system settings:

# worker-userdata-secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: worker-userdata
namespace: baremetal-operator-system
type: Opaque
stringData:
userData: |
#cloud-config
hostname: '{{ ds.meta_data.local-hostname }}'
manage_etc_hosts: true

write_files:
- path: /etc/rancher/rke2/config.yaml
owner: root:root
permissions: '0644'
content: |
token: <RKE2_JOIN_TOKEN>
server: https://192.168.0.1:9345
cni: none
node-ip: '{{ ds.meta_data.local-hostname }}'

- path: /etc/sysctl.d/99-kube-dc.conf
owner: root:root
permissions: '0644'
content: |
fs.inotify.max_user_watches=1524288
fs.inotify.max_user_instances=4024
net.ipv4.ip_forward=1

runcmd:
- sysctl --system
- modprobe nf_conntrack
- echo "nf_conntrack" >> /etc/modules
- systemctl stop systemd-resolved || true
- systemctl disable systemd-resolved || true
- rm -f /etc/resolv.conf
- echo -e "nameserver 8.8.8.8\nnameserver 8.8.4.4" > /etc/resolv.conf
- systemctl enable rke2-agent.service
- systemctl start rke2-agent.service
Security

Replace <RKE2_JOIN_TOKEN> with the actual token from master-1:

sudo cat /var/lib/rancher/rke2/server/node-token

Do not commit the join token or this rendered Secret to Git. Deliver it through the platform's approved encrypted-secret workflow, restrict read access to the provisioning controllers, and rotate it after suspected exposure.

kubectl apply -f worker-userdata-secret.yaml

4.5 Create MachineDeployment

The MachineDeployment controls how many worker nodes to provision and links all the templates together:

# machinedeployment.yaml
apiVersion: cluster.x-k8s.io/v1beta1
kind: MachineDeployment
metadata:
name: kube-dc-workers
namespace: baremetal-operator-system
labels:
cluster.x-k8s.io/cluster-name: kube-dc-mgmt
nodepool: kube-dc-worker-pool
spec:
clusterName: kube-dc-mgmt
replicas: 2 # Number of worker nodes to provision
selector:
matchLabels:
cluster.x-k8s.io/cluster-name: kube-dc-mgmt
nodepool: kube-dc-worker-pool
template:
metadata:
labels:
cluster.x-k8s.io/cluster-name: kube-dc-mgmt
nodepool: kube-dc-worker-pool
spec:
clusterName: kube-dc-mgmt
bootstrap:
dataSecretName: worker-userdata
infrastructureRef:
apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: Metal3MachineTemplate
name: worker-machine-template
version: v1.35.0
kubectl apply -f machinedeployment.yaml

Watch the provisioning:

# Watch BMH state changes
kubectl get bmh -n baremetal-operator-system -w

# Watch Machine status
kubectl get machines -n baremetal-operator-system

# Watch nodes joining the cluster
kubectl get nodes -w

Provisioning time depends on firmware, cleaning policy, image size, and network throughput. Watch the BareMetalHost and Machine conditions and establish a timeout from measurements on the qualified hardware pool.


Phase 5 — Post-Provisioning Network Configuration

After worker nodes join the cluster, configure Kube-OVN networking to include them.

5.1 Update ProviderNetwork

The Kube-OVN ProviderNetwork must include the worker nodes so they can participate in cloud and provider VLAN traffic. If workers have the same trunk NIC name as the masters, they are automatically included via defaultInterface. If NICs differ, add customInterfaces:

# Check what NIC names the workers have
kubectl get bmh worker-1 -n baremetal-operator-system \
-o jsonpath='{.status.hardware.nics[*].name}'

Patch the ProviderNetwork:

apiVersion: kubeovn.io/v1
kind: ProviderNetwork
metadata:
name: ext-cloud
spec:
defaultInterface: eth1 # Default trunk NIC (most nodes)
customInterfaces:
- interface: eno2 # Override for workers with different NIC names
nodes:
- worker-1
- worker-2
autoCreateVlanSubinterfaces: true
preserveVlanInterfaces: true
kubectl apply -f provider-network-patch.yaml

Verify all nodes (masters + workers) are ready in the ProviderNetwork:

kubectl get provider-networks ext-cloud -o jsonpath='{.status.readyNodes}' | jq .
# Expected: ["master-1", "master-2", "master-3", "worker-1", "worker-2"]

5.2 Node Labels

Worker nodes provisioned by Metal3 do not need the kube-ovn/role=master label — that is only for control-plane nodes running OVN Northbound/Southbound databases. However, verify these labels are absent on workers:

# Workers should NOT have these labels:
kubectl get node worker-1 --show-labels | grep -E 'kube-ovn/role|kube-dc-manager'
# Expected: no output
LabelMastersWorkersPurpose
kube-ovn/role=master✅ Yes❌ NoRuns OVN central databases
kube-dc-manager=true✅ Yes❌ NoSchedules Kube-DC control-plane pods
node-role.kubernetes.io/worker❌ No✅ Yes (auto)Standard Kubernetes worker role

5.3 Verify Worker Networking

After the ProviderNetwork is updated, Kube-OVN creates OVS bridges on the worker nodes:

# Check OVS bridges on a worker
kubectl exec -n kube-system -it $(kubectl get pod -n kube-system -l app=ovs-ovn \
--field-selector spec.nodeName=worker-1 -o name) -- ovs-vsctl show

# Check that VLAN subinterfaces were created
kubectl get provider-networks ext-cloud -o jsonpath='{.status.vlans}'
# Expected: ["vlan200","vlan300"] (your cloud and provider VLANs)

Phase 6 — Health Checks and Auto-Remediation

Metal3 supports automated health checking and remediation of worker nodes through CAPI MachineHealthCheck and Metal3RemediationTemplate resources.

6.1 Create Metal3RemediationTemplate

The remediation template defines the strategy for handling unhealthy nodes. The reboot strategy is recommended for bare metal — it power-cycles the server via BMC rather than reprovisioning from scratch:

# metal3remediationtemplate.yaml
apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
kind: Metal3RemediationTemplate
metadata:
name: worker-remediation
namespace: baremetal-operator-system
spec:
template:
spec:
strategy:
type: Reboot
retryLimit: 2 # Retry power-cycle up to 2 times
timeout: 600s # Wait 10 minutes for node to recover

6.2 Create MachineHealthCheck

# machinehealthcheck.yaml
apiVersion: cluster.x-k8s.io/v1beta1
kind: MachineHealthCheck
metadata:
name: worker-healthcheck
namespace: baremetal-operator-system
spec:
clusterName: kube-dc-mgmt
# Match all machines in the worker pool
selector:
matchLabels:
nodepool: kube-dc-worker-pool
# Safety valve: don't remediate if >40% of nodes are unhealthy
maxUnhealthy: 40%
# Time to wait for a new node to join before considering it unhealthy
nodeStartupTimeout: 30m # Bare metal is slow — allow 30 minutes
# Conditions that trigger remediation
unhealthyConditions:
- type: Ready
status: Unknown
timeout: 300s # Node is unreachable for 5 minutes
- type: Ready
status: "False"
timeout: 300s # Node reports NotReady for 5 minutes
# Use Metal3 remediation (power-cycle via BMC)
remediationTemplate:
kind: Metal3RemediationTemplate
apiVersion: infrastructure.cluster.x-k8s.io/v1beta1
name: worker-remediation
kubectl apply -f metal3remediationtemplate.yaml
kubectl apply -f machinehealthcheck.yaml

6.3 How Remediation Works

When a worker node becomes unhealthy:

Metal3 worker remediation sequenceMachineHealthCheck detects a worker whose Ready condition remains Unknown for five minutes and creates a Metal3Remediation request. The CAPM3 remediation controller powers the server off through its BMC, applies the out-of-service taint, then powers it on. The RKE2 agent reconnects and the Node becomes Ready. If retryLimit is exhausted, remediation reports failure and requires operator review rather than assuming automatic replacement.Health checkReady = ?5 minutesRemediation CRMetal3 requestCAPM3off + taintpower onWorker rebootRKE2reconnectsOutcomeReady / failedretryLimit
Remediation is a bounded recovery attempt: health detection creates a Metal3 request, CAPM3 power-cycles and isolates the host, and operators inspect terminal failure before any reviewed reprovision or replacement.

6.4 Monitor Health Checks

# Check MachineHealthCheck status
kubectl get machinehealthcheck -n baremetal-operator-system

# Check for active remediations
kubectl get metal3remediation -n baremetal-operator-system

# Check Machine health conditions
kubectl get machines -n baremetal-operator-system -o wide

Scaling Workers

Scale Up

Increase replicas in the MachineDeployment:

kubectl scale machinedeployment kube-dc-workers \
-n baremetal-operator-system --replicas=4

CAPM3 will select available BareMetalHosts and provision them. Remember to:

  1. Update the ProviderNetwork if new workers have different NIC names
  2. Ensure enough BareMetalHosts are enrolled and in available state

Scale Down

kubectl scale machinedeployment kube-dc-workers \
-n baremetal-operator-system --replicas=1

CAPM3 will:

  1. Cordon and drain the selected worker
  2. Power off the server via BMC
  3. Clean the disk (per automatedCleaningMode)
  4. Return the BMH to available state for future use

Best Practices

Disk Management

  • Set rootDeviceHints on BareMetalHosts to ensure the OS is installed on the correct disk, especially on servers with multiple drives
  • Use automatedCleaningMode: metadata to wipe partition tables between provisions without full disk erase (saves time)
  • For sensitive environments, use automatedCleaningMode: disk for full disk wipe

BMC Security

  • Use Redfish Virtual Media over IPMI when possible — it's more secure and reliable
  • Enable TLS on BMC interfaces and avoid disableCertificateVerification: true in production
  • Rotate BMC credentials regularly and store them as Kubernetes Secrets

Image Management

  • Pre-bake RKE2 agent, kernel modules, and system packages into the OS image to reduce first-boot time
  • Maintain versioned images (e.g., ubuntu-24.04-rke2-v1.35.0.qcow2) for reproducible deployments
  • Host images on a local HTTP server within the management network — downloading from the internet during provisioning is slow and unreliable

Node Reuse

  • Metal3 supports node reuse during rolling upgrades — instead of provisioning a fresh BMH, it reprovisions the same server with a new image
  • Enable this by using the scale-in upgrade strategy on MachineDeployments
  • This significantly reduces upgrade time for bare-metal clusters

Monitoring and Alerting

  • Set up Prometheus alerts for BMH state changes (e.g., error, provisioning failed)
  • Monitor the MachineHealthCheck targets count and current healthy/unhealthy ratios
  • Alert on Metal3Remediation objects being created — they indicate node failures

ProviderNetwork Consistency

  • Use defaultInterface only after verifying the provider interface name on every eligible node; firmware and slot layout can change names even on the same hardware model.
  • Use customInterfaces when a node's provider interface differs from the default.
  • Verify each worker appears in the relevant ProviderNetwork status after joining.

Troubleshooting

BMH Stuck in "registering"

kubectl get bmh worker-1 -n baremetal-operator-system -o yaml | grep -A5 errorMessage

Common causes:

  • BMC IP unreachable from management cluster — check network/firewall
  • Wrong BMC credentials — verify the Secret
  • Unsupported BMC protocol — check Metal3 supported hardware

BMH Stuck in "inspecting"

  • Server failed to PXE boot — check BIOS boot order, PXE NIC settings
  • Ironic ramdisk didn't start — check Ironic logs: kubectl logs -n baremetal-operator-system -l app=ironic
  • Virtual Media mount failed — ensure BMC firmware supports the protocol

Worker Node Not Joining Cluster

# Check RKE2 agent logs on the worker (via BMC console or SSH)
sudo journalctl -u rke2-agent -f

# Common issues:
# - Wrong join token in cloud-init userData
# - master-1 unreachable on management network (check routing)
# - DNS resolution failing (check /etc/resolv.conf)

Kube-OVN Not Working on Worker

kubectl get pods -n kube-system -l app=kube-ovn-cni --field-selector spec.nodeName=worker-1
kubectl logs -n kube-system -l app=kube-ovn-cni --field-selector spec.nodeName=worker-1

Common cause: Worker's trunk NIC not matched in ProviderNetwork. Fix by adding a customInterfaces entry.