Using the Egressip Ipam Operator with a Private ARO Cluster

Prerequisites

• A private ARO cluster that uses OpenShift SDN as its CNI

Deploy the Egressip Ipam Operator

Via GUI

1. Log into the ARO cluster’s Console

2. Switch to the Administrator view

3. Click on Operators -> Operator Hub

4. Search for “Egressip Ipam Operator”

5. Install it with the default settings

or

Via CLI

1. Deploy the egress-ipam-operator

   cat << EOF | kubectl apply -f -
   ---
   apiVersion: v1
   kind: Namespace
   metadata:
     name: egressip-ipam-operator
   ---
   apiVersion: operators.coreos.com/v1alpha1
   kind: Subscription
   metadata:
     name: egressip-ipam-operator
     namespace: openshift-operators
     labels:
       operators.coreos.com/egressip-ipam-operator.egressip-ipam-operator: ''
   spec:
     channel: alpha
     installPlanApproval: Automatic
     name: egressip-ipam-operator
     source: community-operators
     sourceNamespace: openshift-marketplace
     startingCSV: egressip-ipam-operator.v1.2.2
   EOF
   

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Configure EgressIP

1. Create an EgressIPAM resource for your cluster. Update the CIDR to reflect the worker node subnet.

   cat << EOF | kubectl apply -f -
   apiVersion: redhatcop.redhat.io/v1alpha1
   kind: EgressIPAM
   metadata:
     name: egressipam-azure
     annotations:
       egressip-ipam-operator.redhat-cop.io/azure-egress-load-balancer: none
   spec:
     cidrAssignments:
       - labelValue: ""
         CIDR: 10.0.1.0/24
         reservedIPs: []
     topologyLabel: "node-role.kubernetes.io/worker"
     nodeSelector:
       matchLabels:
         node-role.kubernetes.io/worker: ""
   EOF
   

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2. Create test namespaces

   cat << EOF | kubectl apply -f -
   ---
   apiVersion: v1
   kind: Namespace
   metadata:
     name: egressipam-azure-test
     annotations:
       egressip-ipam-operator.redhat-cop.io/egressipam: egressipam-azure
   ---
   apiVersion: v1
   kind: Namespace
   metadata:
     name: egressipam-azure-test-1
     annotations:
       egressip-ipam-operator.redhat-cop.io/egressipam: egressipam-azure
   EOF
   

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3. Check the namespaces have IPs assigned

   kubectl get namespace egressipam-azure-test \
     egressipam-azure-test-1 -o yaml | grep egressips
   

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   The output should look like:

   egressip-ipam-operator.redhat-cop.io/egressips: 10.0.1.8
   egressip-ipam-operator.redhat-cop.io/egressips: 10.0.1.7
   

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4. Check they’re actually set as Egress IPs

   oc get netnamespaces | egrep 'NAME|egress'
   

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   The output should look like:

   NAME                                               NETID      EGRESS IPS
   egressip-ipam-operator                             6374875
   egressipam-azure-test                              6917470    ["10.0.1.8"]
   egressipam-azure-test-1                            16320378   ["10.0.1.7"]
   

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5. Finally check the Host Subnets for Egress IPS

   oc get hostsubnets
   

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   The output should look like:

   NAME                                         HOST                                         HOST IP    SUBNET          EGRESS CIDRS   EGRESS IPS
   private-cluster-bj275-master-0               private-cluster-bj275-master-0               10.0.0.8   10.129.0.0/23
   private-cluster-bj275-master-1               private-cluster-bj275-master-1               10.0.0.7   10.128.0.0/23
   private-cluster-bj275-master-2               private-cluster-bj275-master-2               10.0.0.9   10.130.0.0/23
   private-cluster-bj275-worker-eastus1-zt59t   private-cluster-bj275-worker-eastus1-zt59t   10.0.1.4   10.128.2.0/23                  ["10.0.1.8"]
   private-cluster-bj275-worker-eastus2-bfrwt   private-cluster-bj275-worker-eastus2-bfrwt   10.0.1.5   10.129.2.0/23                  ["10.0.1.7"]
   private-cluster-bj275-worker-eastus3-fgjzk   private-cluster-bj275-worker-eastus3-fgjzk   10.0.1.6   10.131.0.0/23
   

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Test Egress

1. Log into your jumpbox and allow http into firewall

   sudo firewall-cmd --zone=public --add-service=http
   

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2. Install and start apache httpd

   sudo yum -y install httpd
   sudo systemctl start httpd
   

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3. Create a index.html

   echo HELLO | sudo tee /var/www/html/index.html
   

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4. tail apache logs

   sudo tail -f /var/log/httpd/access_log
   

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5. Start an interactive pod in one of your new namespaces

   kubectl run -n egressipam-azure-test -i \
   --tty --rm debug --image=alpine \
   --restart=Never -- wget -O - 10.0.3.4
   

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   The output should look the following (the IP should match the egress IP of your namespace):

   10.0.1.7 - - [03/Feb/2022:19:33:54 +0000] "GET / HTTP/1.1" 200 6 "-" "Wget"
   

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