MetalLB configuration guidelines for subnets¶
Subnet object can define either a MetalLB address range or MetalLB
address pool. A MetalLB address pool may contain one or several address
ranges. The following rules apply to creation of address ranges or pools:
To designate a subnet as a MetalLB address pool or range, use the
ipam/SVC-MetalLBlabel key. Set the label value to
The object must contain the
cluster.sigs.k8s.io/<cluster-name>label to reference the name of the target cluster where the MetalLB address pool is used.
You may create multiple subnets with the
ipam/SVC-MetalLBlabel to define multiple IP address ranges or multiple address pools for MetalLB in the cluster.
The IP addresses of the MetalLB address pool are not assigned to the interfaces on hosts. This subnet is virtual. Do not include such subnets to the L2 template definitions for your cluster.
Subnetobject defines a MetalLB address range, no additional object properties are required.
You can use any number of
Subnetobjects that define a single MetalLB address range. In this case, all address ranges are aggregated into a single MetalLB L2 address pool named
serviceshaving the auto-assign policy enabled.
Intersection of IP address ranges within any single MetalLB address pool is not allowed.
The bare metal provider verifies intersection of IP address ranges. If it detects intersection, the MetalLB configuration is blocked and the provider logs contain corresponding error messages.
Use the following labels to identify the
Subnet object as a MetalLB
address pool and configure the name and protocol for that address pool.
All labels below are mandatory for the
Subnet object that configures
a MetalLB address pool.
Labels to link
Defines that the
Every address pool must have a distinct name.
Configures the auto-assign policy of an address pool. Boolean.
For the address pools defined using the MetalLB Helm chart
values in the
For any service that does not have a specific MetalLB annotation
configured, MetalLB allocates external IPs from arbitrary address
pools that have the auto-assign policy set to
Only for the service that has a specific MetalLB annotation with
the address pool name, MetalLB allocates external IPs from the address
pool having the auto-assign policy set to
Sets the address pool protocol.
The only supported value is
Do not set the same address pool name for two or more
Subnet objects. Otherwise, the corresponding MetalLB address pool
configuration fails with a warning message in the bare metal provider log.
For the auto-assign policy, the following configuration rules apply:
At least one MetalLB address pool must have the auto-assign policy enabled so that unannotated services can have load balancer IPs allocated for them. To satisfy this requirement, either configure one of address pools using the
metallb/address-pool-auto-assign: "true"or configure address range(s) using the
When configuring multiple address pools with the auto-assign policy enabled, keep in mind that it is not determined in advance which pool of those multiple address pools is used to allocate an IP for a particular unannotated service.