Here are seven tips for working with vSphere, including: Logging in via Command Line, dealing with connection problems using ssh to an ESXi host; network performance issues; possible storage problems; Log Files to View in vSphere ESXi 5; network performance troubleshooting; migrating to a virtual machine using VMotion.
1. Logging in via Command Line
By default, the ESXi host does not have ssh enabled, and the method to enable ssh can change based on whether or not the host is ESX or ESXi, and the version of the ESX/ESXi host. There are occasions when you need to login via command line using ssh to troubleshoot problems. In addition, there are alternative methods to get to a command line prompt such as DCUI and TSM, depending on the version and type of host. The ability to manage the host at a command line prompt will allow you to use many different Unix based commands as well as commands introduced by VMware called esxcli commands. The ability to make changes to network, storage and other critical parts of the host, depending on the state of the host, might only be possible at a command line prompt.
In vSphere 5, an administrator can manage the ESXi host from the command line using esxcli commands, such as esxcli network vswitch standard. The esxcli command set was first introduced in vSphere 4.0 and allows an administrator to manage many aspects of the ESXi host from the command line. The commands are available using the Direct Console User Interface (DCUI) to access the ESXi shell, using a remote application like putty to ssh into the host, or through the vSphere Command-Line Interface (vCLI).
The DCUI is similar to the BIOS of a computer and allows you to interact with the host through the console of the ESXi server to perform initial basic configuration and can also be used for troubleshooting using text-based menus. You can use the DCUI to enable local and remote access to the ESXi Shell.
A second method to access the command line is by utilizing an application such as putty to ssh into the ESXi host. In order for ssh to work you must enable the sshd service on the ESXi host.
A third method to run command line commands is thru vCLI. The vCLI provides a command-line interface for ESXi hosts. Multiple ESXi hosts can be managed from a central system with vCLI installed on it. The central system that VMware uses is a downloadable appliance called vMA. vMA enables administrators to run scripts that interact with ESXi hosts and VMware vCenter Server systems without having to authenticate each time. vMA is easy to download, install, and configure through the vSphere Client.
Direct Console User Interface (DCUI)
1. When the DCUI screen appears, press F2 Customize the System and login as root.
2. Scroll to Troubleshooting Options and press Enter.
3. Choose Enable ESXi shell and press Enter.
4. Press Esc until you return to the main DCUI screen.
To enable ssh from the vsphere Client
1. Select the host and click the Configuration tab.
2. Click Security Profile in the Software panel.
3. In the Services area, click Properties.
4. Select ssh and click Options.
5. Change the ssh options. To change the Startup policy across reboots, click Start and stop with host and reboot the host.
6. Click OK.
First method from the Direct Console User Interface (DCUI)
1. Hit Alt+F1, if TSM is enabled, log in with root credentials, else
2. Once the DCUI screen appears, press F2 and login as root to enable the TSM.
3. Navigate down the screen and choose Troubleshooting Options, and press enter.
4. Troubleshooting Options provides additional options for TSM in ESXi 4.1.
<Enable/Disable> Local Tech Support - Access command line via Alt+F1 on the console. <Enable/Disable> Remote Tech Support (ssh) - ssh access on the console of the ESXi host. Modify Tech Support Timeout - Tech Support Mode will be disabled after a certain amount of time.
Second Method from the vSphere Client
1. From the vSphere Client, select the host and click Configuration tab.
2. Then choose Security profile and Properties.
3. Here you can enable Local Tech Support as well as Remote Tech Support (ssh). They are enabled
If the Daemon is running, and disabled if the Daemon is Stopped.
If you want to enable either mode, highlight the mode, then choose Options.
4. Now you can modify the Startup Policy or change the Service to Start, then click OK.