Private ARO Cluster with access via JumpHost

January 21, 2025 8 minute read

This article was originally published at https://cloud.redhat.com/experts/aro/private-cluster/

A Quickstart guide to deploying a Private Azure Red Hat OpenShift cluster.

Prerequisites

Azure CLI

Obviously you’ll need to have an Azure account to configure the CLI against.

MacOS

See Azure Docs for alternative install options.

Install Azure CLI using homebrew
```
 brew update && brew install azure-cli
```
Install sshuttle using homebrew
```
 brew install sshuttle
```

Linux

See Azure Docs for alternative install options.

Import the Microsoft Keys

 sudo rpm --import https://packages.microsoft.com/keys/microsoft.asc

Add the Microsoft Yum Repository

 cat << EOF | sudo tee /etc/yum.repos.d/azure-cli.repo
 [azure-cli]
 name=Azure CLI
 baseurl=https://packages.microsoft.com/yumrepos/azure-cli
 enabled=1
 gpgcheck=1
 gpgkey=https://packages.microsoft.com/keys/microsoft.asc
 EOF

Install Azure CLI

 sudo dnf install -y azure-cli sshuttle

Prepare Azure Account for Azure OpenShift

Log into the Azure CLI by running the following and then authorizing through your Web Browser
```
 az login
```
Make sure you have enough Quota (change the location if you’re not using East US)
```
 az vm list-usage --location "East US" -o table
```
see Addendum - Adding Quota to ARO account if you have less than 36 Quota left for Total Regional vCPUs.

 az provider register -n Microsoft.RedHatOpenShift --wait
 az provider register -n Microsoft.Compute --wait
 az provider register -n Microsoft.Storage --wait
 az provider register -n Microsoft.Authorization --wait

Get Red Hat pull secret

Log into cloud.redhat.com
Browse to https://cloud.redhat.com/openshift/install/azure/aro-provisioned
click the Download pull secret button and remember where you saved it, you’ll reference it later.

Deploy Azure OpenShift

Variables and Resource Group

Set some environment variables to use later, and create an Azure Resource Group.

Set the following environment variables

Change the values to suit your environment, but these defaults should work.

 export AZR_RESOURCE_LOCATION=eastus
 export AZR_RESOURCE_GROUP=openshift-private
 export AZR_CLUSTER=private-cluster
 export AZR_PULL_SECRET=~/Downloads/pull-secret.txt
 export NETWORK_SUBNET=10.0.0.0/20
 export CONTROL_SUBNET=10.0.0.0/24
 export MACHINE_SUBNET=10.0.1.0/24
 export FIREWALL_SUBNET=10.0.2.0/24
 export JUMPHOST_SUBNET=10.0.3.0/24

Create an Azure resource group

 az group create                \
   --name $AZR_RESOURCE_GROUP   \
   --location $AZR_RESOURCE_LOCATION

Create an Azure Service Principal

 AZ_SUB_ID=$(az account show --query id -o tsv)
 AZ_SP_PASS=$(az ad sp create-for-rbac -n "${AZR_CLUSTER}-SP" --role contributor \
   --scopes "/subscriptions/${AZ_SUB_ID}/resourceGroups/${AZR_RESOURCE_GROUP}" \
   --query "password" -o tsv)
 AZ_SP_ID=$(az ad sp list --display-name "${AZR_CLUSTER}-SP" --query "[0].appId" -o tsv)

Networking

Create a virtual network with two empty subnets

Create virtual network

 az network vnet create                                    \
   --address-prefixes $NETWORK_SUBNET                      \
   --name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"   \
   --resource-group $AZR_RESOURCE_GROUP

Create control plane subnet

 az network vnet subnet create                                     \
   --resource-group $AZR_RESOURCE_GROUP                            \
   --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"      \
   --name "$AZR_CLUSTER-aro-control-subnet-$AZR_RESOURCE_LOCATION" \
   --address-prefixes $CONTROL_SUBNET                              

Create machine subnet

 az network vnet subnet create                                       \
   --resource-group $AZR_RESOURCE_GROUP                              \
   --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"        \
   --name "$AZR_CLUSTER-aro-machine-subnet-$AZR_RESOURCE_LOCATION"   \
   --address-prefixes $MACHINE_SUBNET                                

Disable network policies for Private Link Service on the control plane subnet

Optional. The ARO RP will disable this for you if you skip this step.

 az network vnet subnet update                                       \
   --name "$AZR_CLUSTER-aro-control-subnet-$AZR_RESOURCE_LOCATION"   \
   --resource-group $AZR_RESOURCE_GROUP                              \
   --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"        \
   --disable-private-link-service-network-policies true

Egress

Public and Private clusters will have –outbound-type defined to LoadBalancer by default. It means all clusters by default have open egress to the internet through the public load balancer.

To change the default behavior and restrict the Internet Egress you have to set --outbound-type to UserDefinedRouting during cluster creation, and set up a traffic to run through a Firewall solution. This can either be a 3rd party solution or a native Azure solution such as Azure Firewall/Azure NAT Gateway.

If you want to proceed with the UserDefinedRouting the two examples below show how this can be achieved through either Azure NAT gateway or Azure Firewall + Internet Egress.

1a. NAT Gateway

This option replaces the routes for the cluster to go through the Azure NAT GW service for egress vs the LoadBalancer. This will incur extra Azure costs.

You can skip this step if you don’t need to restrict egress.

Create a Public IP

 az network public-ip create -g $AZR_RESOURCE_GROUP \
   -n $AZR_CLUSTER-natgw-ip   \
   --sku "Standard" --location $AZR_RESOURCE_LOCATION

Create the NAT Gateway

 az network nat gateway create \
   --resource-group ${AZR_RESOURCE_GROUP} \
   --name "${AZR_CLUSTER}-natgw" \
   --location ${AZR_RESOURCE_LOCATION} \
   --public-ip-addresses "${AZR_CLUSTER}-natgw-ip"

Get the Public IP of the NAT Gateway

 GW_PUBLIC_IP=$(az network public-ip show -g ${AZR_RESOURCE_GROUP} \
   -n "${AZR_CLUSTER}-natgw-ip" --query "ipAddress" -o tsv)

 echo $GW_PUBLIC_IP

Reconfigure Subnets to use Nat GW

 az network vnet subnet update \
   --name "${AZR_CLUSTER}-aro-control-subnet-${AZR_RESOURCE_LOCATION}"   \
   --resource-group ${AZR_RESOURCE_GROUP}                              \
   --vnet-name "${AZR_CLUSTER}-aro-vnet-${AZR_RESOURCE_LOCATION}"        \
   --nat-gateway "${AZR_CLUSTER}-natgw"

 az network vnet subnet update \
   --name "${AZR_CLUSTER}-aro-machine-subnet-${AZR_RESOURCE_LOCATION}"   \
   --resource-group ${AZR_RESOURCE_GROUP}                              \
   --vnet-name "${AZR_CLUSTER}-aro-vnet-${AZR_RESOURCE_LOCATION}"        \
   --nat-gateway "${AZR_CLUSTER}-natgw"

1b. Firewall + Internet Egress

This option replaces the routes for the cluster to go through Azure Firewall for egress traffic, rather than the LoadBalancer. This will incur extra Azure costs.

You can skip this step if you don’t need to restrict egress.

Make sure you have the AZ CLI firewall extensions

 az extension add -n azure-firewall
 az extension update -n azure-firewall

Create a firewall network, IP, and firewall

 az network vnet subnet create                                 \
   -g $AZR_RESOURCE_GROUP                                      \
   --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"  \
   -n "AzureFirewallSubnet"                                    \
   --address-prefixes $FIREWALL_SUBNET

 az network public-ip create -g $AZR_RESOURCE_GROUP -n fw-ip   \
   --sku "Standard" --location $AZR_RESOURCE_LOCATION

 az network firewall create -g $AZR_RESOURCE_GROUP             \
   -n aro-private -l $AZR_RESOURCE_LOCATION

Configure the firewall and configure IP Config (this may take 15 minutes)

 az network firewall ip-config create -g $AZR_RESOURCE_GROUP    \
   -f aro-private -n fw-config --public-ip-address fw-ip        \
   --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"

 FWPUBLIC_IP=$(az network public-ip show -g $AZR_RESOURCE_GROUP -n fw-ip --query "ipAddress" -o tsv)
 FWPRIVATE_IP=$(az network firewall show -g $AZR_RESOURCE_GROUP -n aro-private --query "ipConfigurations[0].privateIPAddress" -o tsv)

 echo $FWPUBLIC_IP
 echo $FWPRIVATE_IP

Create and configure a route table

 az network route-table create -g $AZR_RESOURCE_GROUP --name aro-udr

 sleep 10

 az network route-table route create -g $AZR_RESOURCE_GROUP --name aro-udr \
   --route-table-name aro-udr --address-prefix 0.0.0.0/0                   \
   --next-hop-type VirtualAppliance --next-hop-ip-address $FWPRIVATE_IP

 az network route-table route create -g $AZR_RESOURCE_GROUP --name aro-vnet   \
   --route-table-name aro-udr --address-prefix 10.0.0.0/16 --name local-route \
   --next-hop-type VirtualNetworkGateway

Create firewall rules for ARO resources

Note: ARO clusters do not need access to the internet, however your own workloads running on them may. You can skip this step if you don’t need any egress at all.

Create a Network Rule to allow all http/https egress traffic (not recommended)

  az network firewall network-rule create -g $AZR_RESOURCE_GROUP -f aro-private \
      --collection-name 'allow-https' --name allow-all                          \
      --action allow --priority 100                                             \
      --source-addresses '*' --dest-addr '*'                                    \
      --protocols 'Any' --destination-ports 1-65535

Create Application Rules to allow to a restricted set of destinations

replace the target-fqdns with your desired destinations

  az network firewall application-rule create -g $AZR_RESOURCE_GROUP -f aro-private     \
      --collection-name 'Allow_Egress'                                                  \
      --action allow                                                                    \
      --priority 100                                                                    \
      -n 'required'                                                                     \
      --source-addresses '*'                                                            \
      --protocols 'http=80' 'https=443'                                                 \
      --target-fqdns '*.google.com' '*.bing.com'

  az network firewall application-rule create -g $AZR_RESOURCE_GROUP -f aro-private     \
      --collection-name 'Docker'                                                        \
      --action allow                                                                    \
      --priority 200                                                                    \
      -n 'docker'                                                                       \
      --source-addresses '*'                                                            \
      --protocols 'http=80' 'https=443'                                                 \
      --target-fqdns '*cloudflare.docker.com' '*registry-1.docker.io' 'apt.dockerproject.org' 'auth.docker.io'

Update the subnets to use the Firewall

Once the cluster is deployed successfully you can update the subnets to use the firewall instead of the default outbound loadbalancer rule.

 az network vnet subnet update -g $AZR_RESOURCE_GROUP            \
 --vnet-name $AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION        \
 --name "$AZR_CLUSTER-aro-control-subnet-$AZR_RESOURCE_LOCATION" \
 --route-table aro-udr

 az network vnet subnet update -g $AZR_RESOURCE_GROUP            \
 --vnet-name $AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION        \
 --name "$AZR_CLUSTER-aro-machine-subnet-$AZR_RESOURCE_LOCATION" \
 --route-table aro-udr

Create the cluster

This will take between 30 and 45 minutes.

az aro create                                                            \
--resource-group $AZR_RESOURCE_GROUP                                     \
--name $AZR_CLUSTER                                                      \
--vnet "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"                    \
--master-subnet "$AZR_CLUSTER-aro-control-subnet-$AZR_RESOURCE_LOCATION" \
--worker-subnet "$AZR_CLUSTER-aro-machine-subnet-$AZR_RESOURCE_LOCATION" \
--apiserver-visibility Private                                           \
--ingress-visibility Private                                             \
--pull-secret @$AZR_PULL_SECRET                                          \
--client-id "${AZ_SP_ID}"                                                \
--client-secret "${AZ_SP_PASS}"

Be sure to add the --outbound-type UserDefinedRouting flag if you are not using the default routing.

Jump Host

With the cluster in a private network, we can create a Jump host in order to connect to it. You can do this while the cluster is being created.

Create jump subnet

 az network vnet subnet create                                \
   --resource-group $AZR_RESOURCE_GROUP                       \
   --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION" \
   --name JumpSubnet                                          \
   --address-prefixes $JUMPHOST_SUBNET                        \
   --service-endpoints Microsoft.ContainerRegistry

Create a jump host

 az vm create --name jumphost                 \
     --resource-group $AZR_RESOURCE_GROUP     \
     --ssh-key-values $HOME/.ssh/id_rsa.pub   \
     --admin-username aro                     \
     --image "RedHat:RHEL:9_1:9.1.2022112113" \
     --subnet JumpSubnet                      \
     --public-ip-address jumphost-ip          \
     --public-ip-sku Standard                 \
     --vnet-name "$AZR_CLUSTER-aro-vnet-$AZR_RESOURCE_LOCATION"

Save the jump host public IP address

 JUMP_IP=$(az vm list-ip-addresses -g $AZR_RESOURCE_GROUP -n jumphost -o tsv \
 --query '[].virtualMachine.network.publicIpAddresses[0].ipAddress')
 echo $JUMP_IP

Use sshuttle to create a ssh vpn via the jump host (use a separate terminal session)

replace the IP with the IP of the jump box from the previous step.
```
 sshuttle --dns -NHr "aro@${JUMP_IP}" $NETWORK_SUBNET
```

Get OpenShift console URL

set these variables to match the ones you set at the start.

 APISERVER=$(az aro show              \
 --name $AZR_CLUSTER                  \
 --resource-group $AZR_RESOURCE_GROUP \
 -o tsv --query apiserverProfile.url)
 echo $APISERVER

Get OpenShift credentials

 ADMINPW=$(az aro list-credentials    \
 --name $AZR_CLUSTER                  \
 --resource-group $AZR_RESOURCE_GROUP \
 --query kubeadminPassword            \
 -o tsv)

log into OpenShift

 oc login $APISERVER --username kubeadmin --password ${ADMINPW}

Delete Cluster

Once you’re done its a good idea to delete the cluster to ensure that you don’t get a surprise bill.

Delete the cluster

 az aro delete -y                       \
   --resource-group $AZR_RESOURCE_GROUP \
   --name $AZR_CLUSTER

Delete the Azure resource group

Only do this if there’s nothing else in the resource group.
```
 az group delete -y \
   --name $AZR_RESOURCE_GROUP
```

Addendum

Adding Quota to ARO account

ARO Console "My Quotas" page with cursor hovering over "Request Adjustment" pencil for a quota named "Total Regional vCPUs"

Visit My Quotas in the Azure Console
Choose the appropriate filters:
1. Set Provider to “Compute”
2. Set Subscription to the subscription you are creating the cluster in
3. Set Region to “East US” and uncheck the other region boxes
Search for the quota name that you want to increase. This may be “Total Regional vCPUs” if you checked that prior to creating the cluster, or it may be a specific resource quota named in a ResourceQuotaExceeded error message. Note that in the latter case, the Azure console uses a localized display name (for example Standard DSv3 Family vCPUs rather than an identifier name standardDSv3Family mentioned in the error message.
Next to the quota name you wish to increase, click the pencil in the Adjustable column to request adjustment
Enter the new desired quota in the New limit text box. By default, a cluster will need 36 additional Regional vCPUs beyond current usage, or the ResourceQuotaExceeded error message will tell you how much more of an additional resource is needed.
Click Submit. You may need to go through additional authentication.
Azure will review your request to adjust your quota. This may take several minutes.

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Ricardo Martins

Private ARO Cluster with access via JumpHost

Prerequisites

Azure CLI

Prepare Azure Account for Azure OpenShift

Get Red Hat pull secret

Deploy Azure OpenShift

Variables and Resource Group

Networking

Egress

1a. NAT Gateway

1b. Firewall + Internet Egress

Create the cluster

Jump Host

Delete Cluster

Addendum

Adding Quota to ARO account

Share on

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