Document image creation, update to coreos 38 and set availability zone.

README.md

 ## Installation process
 
-This document describes the installation process of Coder for the INF110 labs on the R2 OpenStack cluster.
-It should be possible to adapt this to other use cases or OpenStack clusters with minor modifications.
+This document describes the installation process of Coder for the INF110 labs on the R2 OpenStack.
+It should be possible to adapt this to other use cases or OpenStack instances with minor modifications.
+
+### Prerequisites
+
+We will need an OpenStack project, an `openrc` file, and the OpenStack CLI tools. The CLI tools are available in the `nix develop` environment.
+
+```bash
+source openrc # automatically done by the nix env if you have this file
+```
+
+The project should have a Fedora CoreOS image available.
+
+```bash
+openstack image list
+```
+
+If not, it can be created using the following command (after downloading the image from the [Fedora CoreOS website](https://builds.coreos.fedoraproject.org/prod/streams/stable/builds/38.20230806.3.0/x86_64/fedora-coreos-38.20230806.3.0-openstack.x86_64.qcow2.xz)):
+
+```bash
+openstack image create Fedora-CoreOS-38 --file=fedora-coreos-38.20230806.3.0-openstack.x86_64.qcow2 --disk-format=qcow2 --container-format=bare --property os_distro='fedora-coreos'
+```
+
+The project should know about your SSH keypair.
+
+```bash
+openstack keypair list
+```
+
+If not, you can add it using the following command:
+
+```bash
+export KEYPAIR= # your keypair name
+openstack keypair create --public-key ~/.ssh/id_rsa.pub $KEYPAIR
+```
+
+You may want to add the `export KEYPAIR=...` line to your `openrc` file to avoid having to set it each time.
 
 ### Create the cluster template
 
 ```bash
-source openrc # automatically done by the nix env / make sure to have this file
-export KEYPAIR= # your keypair
+export KEYPAIR= # your keypair name
 openstack coe cluster template create \
     --coe kubernetes \
-    --image coreos-35 \
+    --image Fedora-CoreOS-38 \
     --external-network $(openstack network show provider -f json | jq -r .id) \
     --keypair $KEYPAIR \
     --network-driver flannel \
@@ -19,7 +53,7 @@ openstack coe cluster template create \
     --flavor m2.xlarge \
     --master-flavor m1.medium \
     --docker-storage-driver overlay2 \
-    --labels 'auto_healing_enabled=true,auto_scaling_enabled=true,min_node_count=1,max_node_count=100,boot_volume_type=LVM-NVME,etcd_volume_type=LVM-NVME,docker_volume_type=LVM-NVME' \
+    --labels 'auto_healing_enabled=true,auto_scaling_enabled=true,min_node_count=1,max_node_count=100,boot_volume_type=LVM-NVME,etcd_volume_type=LVM-NVME,docker_volume_type=LVM-NVME,availability_zone=nova' \
     --registry-enabled \
     --insecure-registry '10.0.0.99:5000' \
     --server-type vm \
@@ -33,7 +67,13 @@ openstack coe cluster template create \
 openstack coe cluster create --cluster-template coder --node-count 1 inf110
 ```
 
-It can happen that the cluster creation hangs. In that case, log in to the master node and check if it reports that the `etcd` service failed. If so, restart the `etcd` service and the cluster creation should continue.
+You can follow the cluster creation process using the "Orchestration > Stacks" section of the OpenStack dashboard or using the CLI:
+
+```bash
+openstack coe cluster show inf110
+```
+
+It can happen that the cluster creation hangs during the step of creating the master node. In that case, try associating a public IP to the master node. If it still doesn't resolve the problem, log in to the master node and check if it reports that the `etcd` service failed. If so, restart the `etcd` service and the cluster creation should continue.
 
 ```bash
 sudo systemctl restart etcd
@@ -46,7 +86,7 @@ This registry will be used to store the Docker image of the Coder workspace.
 ```bash
 openstack server create \
     --flavor smi-worker \
-    --image coreos-35 \
+    --image Fedora-CoreOS-38 \
     --no-network \
     --security-group default \
     --security-group registry \
@@ -164,7 +204,7 @@ rpm-ostree install helm # no reboot required
 kubectl create namespace coder
 kubectl apply -f /tmp/postgresql-pvc.yml -n coder
 helm repo add bitnami https://charts.bitnami.com/bitnami
-helm install coder-db bitnami/postgresql -n coder -f /tmp/postgresql-values.yml --version 13.0.0 # latest compatible version with Helm 3.2 and thus coreos 35
+helm install coder-db bitnami/postgresql -n coder -f /tmp/postgresql-values.yml --version 13.0.0 # latest compatible version with Helm 3.2 and thus coreos 38
 kubectl create secret generic coder-db-url -n coder --from-literal=url="postgres://coder:coder@coder-db-postgresql.coder.svc.cluster.local:5432/coder?sslmode=disable"
 helm repo add coder-v2 https://helm.coder.com/v2
 helm install coder coder-v2/coder --namespace coder --values /tmp/coder-values.yml --version 2.13.5 # Latest stable version