#+TITLE: OpenShift Ambient Mesh Setup
#+DATE: <2025-08-21 Thu>
#+AUTHOR: James Blair


This is a short demonstration of [[https://istio.io/latest/docs/ambient][Istio Ambient Mesh]] on OpenShift ~4.19~ via the [[https://docs.redhat.com/en/documentation/openshift_container_platform/4.19/html-single/service_mesh/index][OpenShift Service Mesh]] operator.


* Pre-requisites

Before we begin, let's ensure we are logged into our cluster in the terminal and the cluster meets our version requirements.

** Verify cluster auth status

#+NAMEL: Verify cluster login status
#+begin_src tmux
oc version && oc whoami
#+end_src


** Upgrade cluster

The Red Hat demo system environment available was not yet running OpenShift 4.19 so I needed to upgrade it before performing any demo preparation steps.

The first step is to acknowledge the k8s [[https://access.redhat.com/articles/7112216][api deprecations]] between 4.18 and 4.19.

#+NAME: Patch admin acks
#+begin_src tmux
oc -n openshift-config patch cm admin-acks --patch '{"data":{"ack-4.18-kube-1.32-api-removals-in-4.19":"true"}}' --type=merge
#+end_src


Once admin acks are in place we can set the upgrade channel to ~fast-.419~.

#+NAME: Set cluster upgrade channel to 4.19
#+begin_src tmux
oc adm upgrade channel fast-4.19
#+end_src


Now we're ready to trigger the upgrade.

#+NAME: Trigger the cluster upgrade
#+begin_src tmux
oc adm upgrade --to 4.19.9
#+end_src


Before proceeding with any further steps let's wait for the cluster upgrade to complete.

#+NAME: Wait for the upgrade to complete
#+begin_src tmux
oc adm wait-for-stable-cluster
#+end_src


* Install service mesh operator

Our first step to prepare the demonstration is to install the service mesh operator.

#+NAME: Create operator subscription
#+begin_src tmux
cat << EOF | oc apply --filename -
apiVersion: operators.coreos.com/v1alpha1
kind: Subscription
metadata:
  name: servicemeshoperator3
  namespace: openshift-operators
spec:
  channel: stable
  installPlanApproval: Automatic
  name: servicemeshoperator3
  source: redhat-operators
  sourceNamespace: openshift-marketplace
EOF
#+end_src