EKS Anywhere, and MetalLB Load Balancer services

Step-2 Deploy sample application and quick observations

Sample files for the load-balancer testing using a hello-world deployment are already placed inside of $HOME/eks-anywhere/hello-world sub-directory of the EKS-A administrative machine

kubectl apply -f hello-world-deployment.yaml
Once the pods are in running state
kubectl apply -f hello-world-service.yaml

The below logs indicate a sample execution and observation for the above commands in my scenario

cd /home/ubuntu/eks-anywhere/hello-world

kubectl apply -f hello-world-deployment.yaml
deployment.apps/hello-world created

kubectl get pods
NAME                           READY   STATUS    RESTARTS   AGE
hello-world-6df5659cb7-7hwxl   1/1     Running   0          88s
hello-world-6df5659cb7-gdzr7   1/1     Running   0          88s

kubectl create -f hello-world-service.yaml
service/hello-world created

kubectl get svc
NAME          TYPE           CLUSTER-IP     EXTERNAL-IP     PORT(S)        AGE
hello-world   LoadBalancer   10.104.206.5   172.24.165.21   80:31965/TCP   5s
kubernetes    ClusterIP      10.96.0.1                443/TCP        120m

kubectl describe svc hello-world
Name:                     hello-world
Namespace:                default
Labels:                   
Annotations:              
Selector:                 app=hello-world
Type:                     LoadBalancer
IP Family Policy:         SingleStack
IP Families:              IPv4
IP:                       10.104.206.5
IPs:                      10.104.206.5
LoadBalancer Ingress:     172.24.165.21
Port:                       80/TCP
TargetPort:               80/TCP
NodePort:                   31965/TCP
Endpoints:                
Session Affinity:         None
External Traffic Policy:  Cluster
Events:
  Type    Reason       Age    From                Message
  ----    ------       ----   ----                -------
  Normal  IPAllocated  2m22s  metallb-controller  Assigned IP ["172.24.165.21"]

kubectl logs metallb-controller-69bbb4669c-zwlb8 -n metallb-system
{"branch":"HEAD","caller":"level.go:63","commit":"v0.12.1","goversion":"gc / go1.16.14 / amd64","level":"info","msg":"MetalLB controller starting version 0.12.1 (commit v0.12.1, branch HEAD)","ts":"2022-05-09T05:25:40.010545729Z","version":"0.12.1"}
{"caller":"level.go:63","level":"info","msg":"secret succesfully created","op":"CreateMlSecret","ts":"2022-05-09T05:25:40.035930967Z"}
{"caller":"level.go:63","configmap":"metallb-system/metallb","event":"configLoaded","level":"info","msg":"config (re)loaded","ts":"2022-05-09T05:25:40.136808958Z"}
{"caller":"level.go:63","event":"stateSynced","level":"info","msg":"controller synced, can allocate IPs now","ts":"2022-05-09T05:25:40.137910533Z"}
{"caller":"level.go:63","event":"ipAllocated","ip":["172.24.165.21"],"level":"info","msg":"IP address assigned by controller","service":"default/hello-world","ts":"2022-05-09T06:50:06.082923965Z"}
{"caller":"level.go:63","event":"serviceUpdated","level":"info","msg":"updated service object","service":"default/hello-world","ts":"2022-05-09T06:50:06.094906055Z"}

>>>> As you can see from the output, the metalLB controller interacts with the kubernetes service component to allocate the IP to the exposed load-balancer service for hello-world" <<<<

As one can see from the above output, the service name hello-world gets an IP address of 172.24.165.21. This is due to the fact that my static IP ranges 172.21.165.21 to 172.24.165.25

In addition, one can also see from the service description how the MetalLB controller interacts with the Kubernetes control plane to assign the IP address and update the hello-world service.

Step-4 Observe MetalLB constructs

We can use the below gist to issue commands and observe the namespace, pods created after installing MetalLB. You can notice that the above installation creates one controller as a Deployment type pod and another 4 pods via a DaemonSet.

All these pods run in a dedicated namespace called metallb-system

kubectl get namespace
NAME                                STATUS   AGE
capi-kubeadm-bootstrap-system       Active   49m
capi-kubeadm-control-plane-system   Active   49m
capi-system                         Active   49m
capv-system                         Active   49m
cert-manager                        Active   50m
default                             Active   52m
eksa-system                         Active   48m
etcdadm-bootstrap-provider-system   Active   49m
etcdadm-controller-system           Active   49m
kube-node-lease                     Active   52m
kube-public                         Active   52m
kube-system                         Active   52m
metallb-system                      Active   17m <<<<<<<<<<<<<<<<<<<

kubectl get deployments -n metallb-system
NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
metallb-controller   1/1     1            1           26m


kubectl get daemonset -n metallb-system
NAME              DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE
metallb-speaker   4         4         4       4            4           kubernetes.io/os=linux   27m


As you can see a new namespace called metallb-system has been created. Let's observe the pods in this namespace that form the operational context for metalLB.

As you can see below, one pod reflecting the controller component via a deployment and another 4 pods that form a part of the DaemonSet as seen above

kubectl get pods -n metallb-system
NAME                                  READY   STATUS    RESTARTS   AGE
metallb-controller-69bbb4669c-zwlb8   1/1     Running   0          17m
metallb-speaker-pfhdb                 1/1     Running   0          17m
metallb-speaker-qxbp7                 1/1     Running   0          17m
metallb-speaker-wsbls                 1/1     Running   0          17m
metallb-speaker-zxc6q                 1/1     Running   0          17m


An example log of the controller pod

kubectl logs metallb-controller-69bbb4669c-zwlb8 -n metallb-system
{"branch":"HEAD","caller":"level.go:63","commit":"v0.12.1","goversion":"gc / go1.16.14 / amd64","level":"info","msg":"MetalLB controller starting version 0.12.1 (commit v0.12.1, branch HEAD)","ts":"2022-05-09T05:25:40.010545729Z","version":"0.12.1"}
{"caller":"level.go:63","level":"info","msg":"secret succesfully created","op":"CreateMlSecret","ts":"2022-05-09T05:25:40.035930967Z"}
{"caller":"level.go:63","configmap":"metallb-system/metallb","event":"configLoaded","level":"info","msg":"config (re)loaded","ts":"2022-05-09T05:25:40.136808958Z"}
{"caller":"level.go:63","event":"stateSynced","level":"info","msg":"controller synced, can allocate IPs now","ts":"2022-05-09T05:25:40.137910533Z"}

The configuration map created as a part of the installation

kubectl get configmap -n metallb-system
NAME               DATA   AGE
kube-root-ca.crt   1      34m
metallb            1      34m

RBAC created as a part of the MetalLB installation

kubectl get serviceaccount -n metallb-system
NAME                 SECRETS   AGE
default              1         35m
metallb-controller   1         35m
metallb-speaker      1         35m

kubectl get role -n metallb-system
NAME                     CREATED AT
metallb-config-watcher   2022-05-09T05:25:23Z
metallb-controller       2022-05-09T05:25:23Z
metallb-pod-lister       2022-05-09T05:25:23Z

kubectl get rolebinding -n metallb-system
NAME                     ROLE                          AGE
metallb-config-watcher   Role/metallb-config-watcher   36m
metallb-controller       Role/metallb-controller       36m
metallb-pod-lister       Role/metallb-pod-lister       36m

We can easily observe the simplicity with which we can induce a software defined load balancer in a Kubernetes setup. That’s it for now. Hope you found the article insightful and easy to get started with deploying MetalLB on EKS Anywhere clusters
cheers


Ambar Hassani

#iwork4dell