Add VM size parameter and clarify defaults in BYO CNI cluster script

Co-authored-by: tamilmani1989 <1103826+tamilmani1989@users.noreply.github.com>

Author: Copilot

hack/aks/README-byocni.md

@@ -38,6 +38,7 @@ cd /path/to/azure-container-networking
     --cluster my-cluster \
     --subscription YOUR_SUBSCRIPTION_ID \
     --networking-mode swift \
+    --vm-size Standard_D2s_v3 \
     --cni-plugin cilium \
     --cns-version v1.6.0 \
     --cilium-dir 1.16 \
@@ -54,13 +55,16 @@ cd /path/to/azure-container-networking
 
 ## Configuration Options
 
+All parameters have sensible defaults as specified below. Only the `--subscription` parameter is required.
+
 | Parameter | Description | Default |
 |-----------|-------------|---------|
 | `--cluster` | Name of the AKS cluster | `byocni-cluster` |
 | `--subscription` | Azure subscription ID | *Required* |
 | `--resource-group` | Resource group name | Same as cluster name |
 | `--azcli` | Azure CLI command | `az` |
 | `--kubernetes-version` | Kubernetes version for the cluster | `1.33` |
+| `--vm-size` | Azure VM size for cluster nodes | `Standard_B2s` |
 | `--networking-mode` | Networking mode (overlay, swift, nodesubnet, dualstack-overlay, vnetscale-swift) | `overlay` |
 | `--no-kube-proxy` | Create cluster without kube-proxy | `true` |
 | `--with-kube-proxy` | Create cluster with kube-proxy | Overrides --no-kube-proxy |

hack/aks/create-byocni-cluster.sh

@@ -22,6 +22,7 @@ DEFAULT_IPV6_HP_BPF_VERSION=""
 DEFAULT_CNS_IMAGE_REPO="MCR"
 DEFAULT_AZCLI="az"
 DEFAULT_KUBERNETES_VERSION="1.33"
+DEFAULT_VM_SIZE="Standard_B2s"
 
 # Script configuration
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -43,6 +44,7 @@ OPTIONS:
     -g, --resource-group GROUP      Resource group name (default: same as cluster name)
     -z, --azcli AZCLI_COMMAND      Azure CLI command (default: ${DEFAULT_AZCLI})
     -k, --kubernetes-version VER    Kubernetes version for the cluster (default: ${DEFAULT_KUBERNETES_VERSION})
+    -v, --vm-size VM_SIZE           Azure VM size for cluster nodes (default: ${DEFAULT_VM_SIZE})
     -n, --networking-mode MODE      Networking mode: overlay, swift, nodesubnet, dualstack-overlay, vnetscale-swift (default: ${DEFAULT_NETWORKING_MODE})
     --no-kube-proxy                 Create cluster without kube-proxy (default: ${DEFAULT_NO_KUBE_PROXY})
     --with-kube-proxy               Create cluster with kube-proxy (overrides --no-kube-proxy)
@@ -325,7 +327,7 @@ create_cluster() {
     fi
 
     # Build make command with optional GROUP parameter
-    local make_cmd="AZCLI=${AZCLI} CLUSTER=${CLUSTER_NAME} SUB=${SUBSCRIPTION} K8S_VER=${KUBERNETES_VERSION} LTS=${lts_setting}"
+    local make_cmd="AZCLI=${AZCLI} CLUSTER=${CLUSTER_NAME} SUB=${SUBSCRIPTION} K8S_VER=${KUBERNETES_VERSION} VM_SIZE=${VM_SIZE} LTS=${lts_setting}"
     if [[ -n "${RESOURCE_GROUP}" ]]; then
         make_cmd="${make_cmd} GROUP=${RESOURCE_GROUP}"
     fi
@@ -503,6 +505,7 @@ IPV6_HP_BPF_VERSION="${DEFAULT_IPV6_HP_BPF_VERSION}"
 CNS_IMAGE_REPO="${DEFAULT_CNS_IMAGE_REPO}"
 AZCLI="${DEFAULT_AZCLI}"
 KUBERNETES_VERSION="${DEFAULT_KUBERNETES_VERSION}"
+VM_SIZE="${DEFAULT_VM_SIZE}"
 DRY_RUN="false"
 
 while [[ $# -gt 0 ]]; do
@@ -527,6 +530,10 @@ while [[ $# -gt 0 ]]; do
             KUBERNETES_VERSION="$2"
             shift 2
             ;;
+        -v|--vm-size)
+            VM_SIZE="$2"
+            shift 2
+            ;;
         -n|--networking-mode)
             NETWORKING_MODE="$2"
             shift 2
@@ -603,6 +610,7 @@ main() {
     log "  Resource Group: ${RESOURCE_GROUP:-${CLUSTER_NAME}}"
     log "  Azure CLI: ${AZCLI}"
     log "  Kubernetes Version: ${KUBERNETES_VERSION}"
+    log "  VM Size: ${VM_SIZE}"
     log "  Networking Mode: ${NETWORKING_MODE}"
     log "  No Kube-proxy: ${NO_KUBE_PROXY}"
     log "  CNI Plugin: ${CNI_PLUGIN}"