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RedHat OCP/loxilb in-cluster mode

Quick Start Guide with Redhat OCP 4.16 and LoxiLB in-cluster mode

This guide will explain how to:

  • Deploy a single-node Redhat OCP 4.16 cluster
  • Run loxilb in-cluster mode
  • Expose services with loxilb as provider of serviceLB

Pre-requisite

  • Single node to run Redhat OCP 4.16 (or later)
  • Bastion or Host node to consume the services running in same network subnet as OCP node

Topology

For quickly bringing up loxilb with OCP, we will be deploying all components in a single node :

image

All components of loxilb run as part of the OCP cluster in this scenario. loxilb can be used with various HA options as well, but skipped here for simplicity.

Setup Redhat OpenShift Container Platform (OCP) 4.16

Users can follow the official documentation to install a single node OCP cluster

Deploying loxilb in OCP

Use the following command to get the loxilb manifest: 

wget https://raw.githubusercontent.com/loxilb-io/kube-loxilb/refs/heads/main/manifest/in-cluster/loxilb-nobgp.yaml

Change the contents of loxilb.yaml as following: 

command: [ "/root/loxilb-io/loxilb/loxilb", "--egr-hooks", "--whitelist=enp0s3" ]
As one could guess, this is the name of system interface. This should be the interface which is associated with br-ex of OCP node. To confirm one can open the OCP web console and check under "Networking->NodeNetworkState" :

image

Now apply the loxilb manifest file : 

oc apply -f loxilb-nobgp.yaml

Deploying kube-loxilb in OCP

kube-loxilb is used as loxilb's operator with Kubernetes. Get the manifest file : 

wget https://raw.githubusercontent.com/loxilb-io/kube-loxilb/refs/heads/main/manifest/in-cluster/kube-loxilb.yaml

Change the contents of kube-loxilb.yaml "args" to the following (leaving others commented) : 

        args:
          #- --loxiURL=http://192.168.80.10:11111
          - --cidrPools=defaultPool=192.168.80.100/32
          - --setRoles=0.0.0.0
          #- --setBGP=64512
          #- --listenBGPPort=1791
          #- --monitor
          #- --extBGPPeers=50.50.50.1:65101,51.51.51.1:65102
          #- --setLBMode=1
The CIDR is set to any unused IP/subnet in the local network.

Apply the yaml contents : 

oc apply -f kube-loxilb.yaml

Spawn a test pod and create a LB service

cat << EOF | oc apply -f -
apiVersion: v1
kind: Service
metadata:
  name: tcp-lb-onearm
  annotations:
    loxilb.io/liveness: "yes"
    loxilb.io/lbmode: "onearm"
spec:
  externalTrafficPolicy: Local
  loadBalancerClass: loxilb.io/loxilb
  selector:
    what: tcp-onearm-test
  ports:
    - port: 55002
      targetPort: 80 
  type: LoadBalancer
---
apiVersion: v1
kind: Pod
metadata:
  name: tcp-onearm-test
  labels:
    what: tcp-onearm-test
spec:
  containers:
    - name: tcp-onearm-test
      image: ghcr.io/loxilb-io/nginx:stable
      ports:
        - containerPort: 80
EOF
For detailed explanation of various annotations, please check this guide.

Check the status

Check Kubernetes services status :

$ oc get svc
NAME            TYPE           CLUSTER-IP    EXTERNAL-IP          PORT(S)           AGE
kubernetes      ClusterIP      10.245.0.1    <none>               443/TCP           31m
tcp-lb-onearm   LoadBalancer   10.245.2.83   llb-192.168.80.100   55002:32057/TCP   45s

Check create LB rules in loxilb pod :

$ oc get pods -A |grep loxilb-lb
kube-system    loxilb-lb-sws2g                  1/1     Running   0          4m14s

$ oc exec -it -n kube-system loxilb-lb-sws2g  -- loxicmd get lb -o wide
|     EXT IP     | SEC IPS | HOST | PORT  | PROTO |         NAME          | MARK | SEL |  MODE  |    ENDPOINT    | EPORT | WEIGHT | STATE  | COUNTERS |
|----------------|---------|------|-------|-------|-----------------------|------|-----|--------|----------------|-------|--------|--------|----------|
| 192.168.80.100 |         |      | 55002 | tcp   | default_tcp-lb-onearm |    0 | rr  | onearm | 192.168.80.250 | 31640 |      1 | active | 11:818   |

Connect from host/client

$ curl http://192.168.80.100:55002
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>