OPENSHIFTP-145: cluster network mtu can be externally configured

main.tf

@@ -152,6 +152,7 @@ module "support" {
   worker                   = var.worker
   nfs_server               = module.vpc_support.vpc_support_server_ip
   nfs_path                 = var.nfs_path
+  cluster_network_mtu      = var.cluster_network_mtu
 }
 
 module "worker" {

modules/4_pvs_support/pvs_support.tf

@@ -196,13 +196,25 @@ resource "null_resource" "adjust_mtu" {
     timeout     = "${var.connection_timeout}m"
   }
 
-  # The mtu.network.to was originally targetting 9000, and has been moved to 1350 based on the VPC/IBM Cloud configurations.
+  # The mtu.network.to was originally targetting 9000, and has been moved to ${var.cluster_network_mtu} (Default 1350) based on the VPC/IBM Cloud configurations. User can override it by setting desired value in var.tfvars file
   # we previously supported OpenShiftSDN since it's deprecation we have removed it from automation.
   provisioner "remote-exec" {
     inline = [<<EOF
 export HTTPS_PROXY="http://${var.vpc_support_server_ip}:3128"
-oc patch Network.operator.openshift.io cluster --type=merge --patch \
-    '{"spec": { "migration": { "mtu": { "network": { "from": 1400, "to": 1350 } , "machine": { "to" : 9100} } } } }'
+
+EXISTING_MTU=$(oc get network cluster -o yaml | grep -i clusterNetworkMTU | awk '{print $2}')
+
+if [ $EXISTING_MTU != ${var.cluster_network_mtu} ]
+then
+  echo "Setting clusterNetworkMTU to ${var.cluster_network_mtu}"
+  output=$(oc patch Network.operator.openshift.io cluster --type=merge --patch \
+    '{"spec": { "migration": { "mtu": { "network": { "from": '$EXISTING_MTU', "to": ${var.cluster_network_mtu} } , "machine": { "to" : 9100} } } } }')
+  echo "Patch command output is $output"
+
+else
+  echo "clusterNetworkMTU is already set to ${var.cluster_network_mtu}"
+fi
+
 EOF
     ]
   }
@@ -309,6 +321,25 @@ do
   sleep 30
 done
 
+# Check clusterNetworkMTU
+cl_network_mtu=$(oc get network cluster -o yaml | grep -i clusterNetworkMTU | awk '{print $2}')
+echo "(DEBUG) clusterNetworkMTU FOUND?: $${cl_network_mtu}"
+
+# While loop waits for clusterNetworkMTU=var.cluster_network_mtu (Default 1350) till timeout has not reached
+while [[ "$(oc get network cluster -o yaml | grep -i clusterNetworkMTU | awk '{print $2}')" != "${var.cluster_network_mtu}" ]]
+do
+  echo "waiting for clusterNetworkMTU to be ${var.cluster_network_mtu}"
+  sleep 30
+
+  start_counter=$(expr $start_counter + 1)
+
+  # Break the loop if timeout occurs
+  if [ $start_counter -gt $timeout_counter ]
+  then
+    break
+  fi
+done
+
 RENDERED_CONFIG=$(oc get mcp/worker -o json | jq -r '.spec.configuration.name')
 CHECK_CONFIG=$(oc get mc $${RENDERED_CONFIG} -ojson 2>&1 | grep TARGET_MTU=9100)
 while [ -z "$${CHECK_CONFIG}" ]

modules/4_pvs_support/variables.tf

@@ -19,6 +19,7 @@ variable "powervs_machine_cidr" {}
 variable "keep_dns" {}
 variable "nfs_server" {}
 variable "nfs_path" {}
+variable "cluster_network_mtu" {}
 variable "worker" {
   type = object({ count = number, memory = string, processors = string })
   default = {

variables.tf

@@ -317,6 +317,11 @@ variable "use_zone_info_for_names" {
   description = "Add zone info to instance name or not"
 }
 
+variable "cluster_network_mtu" {
+  type        = number
+  description = "MTU value for the OCP cluster network"
+  default     = 1350
+}
 ################################################################
 # Additional Settings
 ################################################################