Unable to change the Linux hostname using custom extension

Question

I am trying to change the linux hostname using ARM Template , find my code below

{
"type": "Microsoft.Compute/virtualMachines/extensions",
"apiVersion": "2019-12-01",
"name": "[concat('VMName','/HostnameChange')]",
"location": "Central US",
"copy": {
"name": "HostnameCopy",
"count": 1
},
"properties": {
"publisher": "Microsoft.Azure.Extensions",
"type": "CustomScript",
"typeHandlerVersion": "2.1",
"autoUpgradeMinorVersion": true,
"settings": {
"skipDos2Unix": false
},
"protectedSettings": {
"commandToExecute": "hostnamectl set-hostname VMName"
}
}
}

Kindly help me to resolve

Answer 1

@Somasundharam Arjunan

What Linux OS you are seeing the issue?
If its Suse, it could be due to the DHCLIENT, so in your custom script run this command try

sed -i 's/DHCLIENT_SET_HOSTNAME="yes"/DHCLIENT_SET_HOSTNAME="no"/' /etc/sysconfig/network/dhcp and you may need to add reboot at the end of the script.

Can you see what hostname is being displayed for these commands hostname cat /etc/hostname and cat /var/lib/waagent/published_hostname.
From this log (waagent.log) you can see what operation is overriding the hostname change cat /var/log/waagent.log , to see if any issue with Azure Linux Agent.

One more suggestion is to grep -r at /etc and see if there are any files with old hostname, try to change them and reboot the VM.