Azure Kubernetes Services (AKS) upgrade guide

This topic describes how to upgrade Kubernetes in your Azure Kubernetes Service (AKS) Domino deployment. AKS is hosted on Azure.

Important

Immediately after the Kubernetes upgrade, you must upgrade Domino to a compatible version of Kubernetes. Domino will not work as expected until this is completed.

For example, after upgrading Kubernetes to v1.22, you must upgrade to Domino v5.2 or later. Kubernetes v1.22 is not compatible with older versions of Domino. Similarly, after upgrading to Kubernetes 1.23 or 1.24, you must upgrade to Domino v5.3 or later.

Prerequisites

To upgrade Kubernetes on Azure, you must have a Unix or Linux terminal with the following:

Azure CLI installed.
Kubectl installed.

Use environment variables to set the values of IDs, names, and labels. This simplifies the commands you’ll run when you upgrade:

export SUB_ID=<Id of the subscription where AKS was deployed>
export RG_NAME=<Name of the resource group where AKS was deployed>
export CLUSTER_NAME=<The name of the cluster where domino is deployed>

Get cluster credentials

If you aren’t already signed in to Azure CLI, run:
```
az login
```
Protect your current kubeconfig from being overwritten:
```
export KUBECONFIG=$(pwd)/kubeconfig
```

Get the remote kubeconfig:

az aks get-credentials --subscription $SUB_ID --resource-group $RG_NAME --name $CLUSTER_NAME -f $KUBECONFIG

Disable the Disruption Budgets

You must temporarily disable the PodDisruptionBudget (PDB) for certain services. To do this, back up the PDBs, delete the original PDBs, then update Kubernetes and restore the PDBs from the backup after the update is complete.

Back up the PDBs:

kubectl get pdb -n domino-platform -o yaml mongodb-arbiter > mongodb-arbiter.yml
kubectl get pdb -n domino-platform -o yaml mongodb-primary  > mongodb-primary.yml
kubectl get pdb -n domino-platform -o yaml mongodb-secondary > mongodb-secondary.yml

Delete the PDBs:

kubectl delete pdb -n domino-platform mongodb-arbiter
kubectl delete pdb -n domino-platform mongodb-primary
kubectl delete pdb -n domino-platform mongodb-secondary

Update the cluster

Check for available AKS cluster upgrades:

az aks get-upgrades --subscription $SUB_ID --resource-group $RG_NAME --name $CLUSTER_NAME --output table

Run the cluster update:

az aks upgrade --subscription $SUB_ID --resource-group $RG_NAME --name $CLUSTER_NAME --kubernetes-version <version-number>

Note	The previous step might take several minutes to complete.

Kubernetes v1.24

If you upgrade to Kubernetes 1.24, add a path annotation for the nginx-ingress-controller probe:
kubectl annotate svc -n domino-platform nginx-ingress-controller "service.beta.kubernetes.io/azure-load-balancer-health-probe-request-path=/healthz"
```
kubectl annotate svc -n domino-platform nginx-ingress-controller "service.beta.kubernetes.io/azure-load-balancer-health-probe-request-path=/healthz"
```
Important
You must annotate this path to avoid 504 Gateway Time-out errors. This is because, in AKS version 1.24, the path no longer defaults to /healthz.

Restore the disruption budgets

Run these commands from the same folder as the backup:

kubectl apply -f mongodb-arbiter.yml
kubectl apply -f mongodb-primary.yml
kubectl apply -f mongodb-secondary.yml