Category Archives: Automation

Powercli script to run commands on ESX hosts

Recently while working with a customer on a large scale NSX environment we hit a product bug that required us to increase the memory allocated to the vswfd (vShield-Statefull-Firewall) process on the ESXi host.

There were 2 main reasons we hit this issue,
1. Due to high churn in the distributed firewall there was a significantly high number of updates the vsfwd daemon has to process
2. Non-optimized way of allocating memory for these updates caused vsfwd to consume all of its allocated memory.

Anyway the purpose of this article is not to talk about the issue but a way to automate the process of updating the vsfwd memory on the ESXi hosts. As this was a large scale environment it was not ideal to manually edit config files on every ESXi host to increase the memory. Automating this process would eliminate errors arising due to manual intervention and keeps configuration consistent across all hosts.

I started writing the script in python and was going to leverage the paramiko module to SSH and run commands. I quickly found it a bit difficult to manage the numerous host IP addresses with python so I switched to PowerCli as I could use the Get-VMhost command to get the list of hosts in a cluster.

I’ve put the script up on the github for anyone interested – script

Until next time and here’s to learning something new each day!!!