MetalLB load-balancer for Kubernetes¶

Available since MKE 3.7.0

MetalLB is a load-balancer implementation for bare metal Kubernetes clusters, using standard routing protocols.

Prerequisites¶

An MKE cluster that is running Kubernetes 1.13.0 or later, which does not already have network load-balancing functionality.
A cluster network configuration that is compatible with MetalLB.
Available IPv4 addresses that MetalLB can allocate.
BGP operating mode requires one or more routers capable of communicating with BGP.
When using the L2 operating mode, traffic on port 7946 must be allowed between nodes, as required by memberlist. You can configure TCP, UDP, and other ports.
Verification that kube-proxy is running in iptables mode.
Verification of the absence of any cloud provider configuration

Install MetalLB¶

You use the MKE configuration file to install MetalLB:

Obtain the current MKE configuration file for the cluster.
Set cluster_config.metallb_config.enabled to true.
Configure at least one IP address pool by setting the values in the cluster_config.metallb_config.metallb_ip_addr_pool.name and cluster_config.metallb_config.metallb_ip_addr_pool.external_ip values.
Caution
- Make sure to provide correct IP addresses in CIDR format.
- MetalLB pool name values must adhere to the RFC 1123 international format:
  
  A lowercase RFC 1123 subdomain must consist of lower case alphanumeric characters, - or ., and must start and end with an alphanumeric character. For example, example.com, regex used for validation is ‘[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*’)
Example IP address pool settings:
```
[cluster_config.metallb_config]
    enabled = true
    [[cluster_config.metallb_config.metallb_ip_addr_pool]]
        name = "example1”
        external_ip = ["192.168.10.0/24", "192.168.1.0/24"]

    [[cluster_config.metallb_config.metallb_ip_addr_pool]]
        name = "example2"
        external_ip = ["52.205.10.1/24"]
```
When multiple address pools are configured, MKE advertises all of the pools by default. To request assignment from a specific pool, users can add metallb.universe.tf/address-pool annotation to the service, with the name of the address pool as the annotation value. In the event that no such annotation is added, MetalLB will assign an IP from one of the configured pools.

You can configure both public and private IPs, based on your environment. MKE allows you to define unlimited address pools and is type-agnostic.
Upload the modified MKE configuration file and allow at least 5 minutes for MKE to propagate the configuration changes throughout the cluster.

Verify the successful installation of MetalLB in the cluster.

Verify the creation of the metallb-system namespace:

kubectl get ns metallb-system

Example output:

NAME             STATUS   AGE
metallb-system   Active   93s

Verify that all MetalLB components are running in the system:

Verify the Pods:

kubectl get pods -n metallb-system

Example output:

NAME                          READY   STATUS    RESTARTS   AGE
controller-669d7d89b5-58s2g   1/1     Running   0          119s
speaker-cchsw                 1/1     Running   0          119s
speaker-ph96f                 1/1     Running   0          119s

Verify the Daemonsets:

kubectl get daemonsets -n metallb-system

Example output:

NAME      DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
speaker   2         2         2       2            2
kubernetes.io/os=linux   28m

Verify the Deployments:

kubectl get deployment -n metallb-system

Example output:

NAME         READY   UP-TO-DATE   AVAILABLE   AGE
controller   1/1     1            1           29m

Verify the Services:

kubectl get services -n metallb-system

Example output:

NAME              TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)   AGE
webhook-service   ClusterIP   10.96.18.104   <none>        443/TCP   29m

Verify the creation of the Custom Resource Defintions:

kubectl get crd -n metallb-system

Example output:

NAME                           CREATED AT
addresspools.metallb.io        2023-03-16T17:11:02Z
bfdprofiles.metallb.io         2023-03-16T17:11:03Z
bgpadvertisements.metallb.io   2023-03-16T17:11:03Z
bgppeers.metallb.io            2023-03-16T17:11:03Z
communities.metallb.io         2023-03-16T17:11:03Z
ipaddresspools.metallb.io      2023-03-16T17:11:03Z
l2advertisements.metallb.io    2023-03-16T17:11:03Z

Verify the creation of the specified IP pools:

kubectl get IPAddressPools -n metallb-system

Example output:

NAME       AUTO ASSIGN   AVOID BUGGY IPS   ADDRESSES
example1   true          false             ["192.168.10.0/24","192.168.1.0/24"]
example2   true          false             ["52.205.10.1/24"]

Uninstall Metallb¶

To uninstall MetalLB you need only update the MKE configuration file.

Obtain the current MKE configuration file for the cluster.
Set cluster_config.metallb_config.enabled to false.
Upload the modified MKE configuration file and allow at least 5 minutes for MKE to propagate the configuration changes throughout the cluster.

Verify the successful uninstall of MetalLB in the cluster.

Verify that no MetalLB components are running in the system.

Verify the Pods:

kubectl get pods -n metallb-system

Example output:

No resources found in metallb-system namespace.

Verify the Daemonsets:

kubectl get daemonsets -n metallb-system

Example output:

No resources found in metallb-system namespace.

Verify the Deployments:

kubectl get deployment -n metallb-system

Example output:

No resources found in metallb-system namespace.

Verify the Services:

kubectl get services -n metallb-system

Example output:

No resources found in metallb-system namespace.

Verify the deletion of all IP address pools.

kubectl get IPAddressPools -n metallb-system

Example output:

No resources found in metallb-system namespace.