Author: Danilo Chiacchio

The vim-cmd utility is one of the most useful command-line tools available on a VMware ESXi host. It allows administrators to inspect and manage virtual machines directly from the ESXi Shell or through an SSH session, which can be especially useful when troubleshooting a host or when the vSphere Client is unavailable. In this practical guide, I will show several useful vim-cmd commands with examples, including how to list registered virtual machines, identify a VMID, check VM configuration and power state, retrieve guest information, work with snapshots, inspect ESXi host information, and perform basic maintenance operations. Many vim-cmd operations require…

Using iPerf3 on an ESXi host is a practical way to measure network throughput between virtualization endpoints and verify whether a specific network path is delivering the performance expected from the infrastructure. In this lab, I will use the iPerf3 utility available on ESXi to test traffic between two ESXi hosts and between an ESXi host and a virtual machine. This can be useful when troubleshooting low throughput on networks used by services such as vSAN, vMotion, management, or other VMkernel-based traffic. The most important part of an iPerf test is making sure that the traffic uses the network path…

Last week, I rebooted a physical Red Hat Enterprise Linux 8 server after applying security updates that included a new kernel. The reboot itself completed normally, but there was one unexpected result: none of the Docker containers came back online. This was a DEV server running Docker Engine with several containers. I expected the applications to return automatically after the host reboot, but every container remained stopped until I started them manually. The problem was not the kernel update or Docker itself. The containers had been created without a restart policy, so Docker had no instruction to start them again…