What is kube-loxilb ?

kube-loxilb is loxilb's implementation of kubernetes service load-balancer spec which includes support for load-balancer class, advanced IPAM (shared or exclusive), lb services on multus pods etc. kube-loxilb runs as a deloyment set in kube-system namespace.

How is kube-loxilb different from loxi-ccm ?

Another loxilb component known as loxi-ccm also provides implementation of kubernetes load-balancer spec but it runs as a part of cloud-provider and provides load-balancer life-cycle management as part of it. If one does not need a cloud-provider or wants to integrate loxilb with their existing cloud-provider, one can use or include loxi-ccm as a part of it. If not kube-loxilb is the right component to use.

kube-loxilb is a standalone implementation of kubernetes load-balancer spec which does not depend on cloud-provider. It runs as a kube-system deployment and provisions load-balancer based on load-balancer class. It only acts on load-balancers for the LB classes that is provided by itself. This also allows us to have different load-balancers working together in the same K8s environment.

How to use kube-loxilb ?

1.Make sure loxilb docker is downloaded and installed properly. One can follow guides here or refer to various other documentation

2.Download the loxilb config yaml :

wget https://github.com/loxilb-io/kube-loxilb/raw/main/manifest/kube-loxilb.yaml

3.Modify arguments as per user's needs :

args:
        - --loxiURL=http://12.12.12.1:11111
        - --externalCIDR=123.123.123.1/24
        #- --externalSecondaryCIDRs=124.124.124.1/24,125.125.125.1/24
        #- --externalCIDR6=3ffe::1/96
        #- --monitor
        #- --setBGP=false
        #- --setLBMode=1
        #- --setUniqueIP=false

The arguments have the following meaning :

• loxiURL : API server address of loxilb. This is the docker IP address loxilb docker of Step 1.
• externalCIDR : CIDR or IPAddress range to allocate addresses from. By default address allocated are shared for different services(shared Mode)
• externalCIDR6 : Ipv6 CIDR or IPAddress range to allocate addresses from. By default address allocated are shared for different services(shared Mode)
• monitor : Enable liveness probe for the LB end-points (default : unset)
• setBGP : Use BGP to advertise this service (default :false). Please check here how it works.
• setLBMode : 0, 1, 2
  0 - default (only DNAT, preserves source-IP)
  1 - onearm (source IP is changed to load balancer’s interface IP)
  2 - fullNAT (sourceIP is changed to virtual IP)
• setUniqueIP : Allocate unique service-IP per LB service (default : false)
• externalSecondaryCIDRs: Secondary CIDR or IPAddress ranges to allocate addresses from in case of multi-homing support

4. Apply the following :

kubectl apply -f kube-loxilb.yaml

5. The above should make sure kube-loxilb is successfully running. Check kube-loxilb is running :

kubectl get pods -A | grep kube-loxilb

6. Finally to create service LB, we can use and apply the following template yaml :
   (Note - Check loadBalancerClass and other loxilb specific annotation)

apiVersion: v1
kind: Service
metadata:
  name: iperf-service
  annotations:
    # If there is a need to do liveness check from loxilb
    loxilb.io/liveness: "yes"
    # Specify LB mode - one of default, onearm or fullnat 
    loxilb.io/lbmode: "default"
    # Specify loxilb IPAM mode - one of ipv4, ipv6 or ipv6to4 
    loxilb.io/ipam: "ipv4"
    # Specify number of secondary networks for multi-homing
    # Only valid for SCTP currently
    # loxilb.io/num-secondary-networks: "2 
spec:
  loadBalancerClass: loxilb.io/loxilb
  selector:
    what: perf-test
  ports:
    - port: 55001
      targetPort: 5001
  type: LoadBalancer
---
apiVersion: v1
kind: Pod
metadata:
  name: iperf1
  labels:
    what: perf-test
spec:
  containers:
    - name: iperf
      image: eyes852/ubuntu-iperf-test:0.5
      command:
        - iperf
        - "-s"
      ports:
        - containerPort: 5001

Users can change the above as per their needs.

7. Verify LB service is created

kubectl get svc