I’ve started this post as a way to track any ESXi CLI tips, tricks/shortcuts that I think may be useful for the VCAP-DCA exam, though should also be of use generally. Thought I haven’t yet taken the exam myself (though will be shortly!), a lot of the posts written by those that have taken the exam highlight the fact that time management is a big issue. With this in mind, I starting thinking about ways to find things quickly using the available tools. This post is the result of some of the things I think may be useful, and there will likely be further post in time – if there are any tips/shortcuts you use please let me know in the comments section! I’ll start by looking at using ‘grep’ to help find ESXi advanced settings quickly.
Using grep to find ESXi Advanced Settings
I think there will be a lot of focus on ESXi host advanced settings on the VCAP-DCA exam. You can list all the advanced settings using esxli by running:
~ # esxcli system settings advanced list
The output for this will fill many pages so I tend to pipe it to the less command:
~ # esxcli system settings advanced list | less
Once in ‘less’ you can search the output, for example by typeing ‘/mem’. Another way to search the output is to use the ‘grep’ command. For example, running the following will find all entries in the output that contain ‘mem’:
~ # esxcli system settings advanced list | grep -i mem
To be more specific we can search for lines that include both ‘Path’ and ‘mem’, which will display all the settings that include ‘mem’:
~ # esxcli system settings advanced list | grep -i -e 'Path.*mem' Path: /Mem/UseLowMemFirst Path: /Mem/UseStressLowMemory Path: /Mem/BalancePeriod Path: /Mem/SamplePeriod Path: /Mem/SampleMapLargeThreshold Path: /Mem/IdleTax Path: /Mem/IdleTaxType
To include the full description and other parameter values, add ‘-A 9’ to the command, which will show the 9 lines that follow the matched pattern. For example:
~ # esxcli system settings advanced list | grep -i -e 'Path.*mem' -A 9 Path: /Mem/UseLowMemFirst Type: integer Int Value: 0 Default Int Value: 0 Min Value: 0 Max Value: 1 String Value: Default String Value: Valid Characters: Description: Preferred use of low memory if no type is specified
Alternatively, you could search the description line then display the previous 9 lines in order to get the setting path:
~ # esxcli system settings advanced list | grep -i -e 'Description.*compression' -B 9 Path: /Mem/MemZipEnable Type: integer Int Value: 1 Default Int Value: 1 Min Value: 0 Max Value: 1 String Value: Default String Value: Valid Characters: Description: Enable the memory compression cache
Finding ESXCLI commands using grep
Grep is a great tool, and along with helping to find advanced settings as shown in the examples above, you can also use it to help find esxcli commands. For example, you know that there are some snmp related commands available in esxcli, but can’t remember exactly where the namespace is in the hierarchy? Run:
~ # esxcli esxcli command list | grep snmp system.snmp get system.snmp hash system.snmp set system.snmp test
From the output, it is clear that the snmp commands can be found under the system namespace:
~ # esxcli system
Usage: esxcli system {cmd} [cmd options]
Available Namespaces:
boot Operations relating to host boot that allow manipulation of VMkernel boot time configuration.
coredump Operations pertaining to the VMkernel Core dump configuration.
module Operations that allow manipulation of the VMkernel loadable modules and device drivers. Operations include load, list and setting options.
process Commands relating to running processes.
secpolicy Options related to VMkernel access control subsystem. These options are typically in place for specific workarounds or debugging. These commands should be used at the direction of VMware
Support Engineers.
settings Operations that allow viewing and manipulation of system settings.
stats Access to various system statistics
syslog Operations relating to system logging
visorfs Operations pertaining to the visorfs memory filesytem.
hostname Operations pertaining the network name of the ESX host.
maintenanceMode Command to manage the system's maintenance mode.
shutdown Command to shutdown the system.
snmp Commands pertaining to SNMPv1/v2c/v3 Agent configuration.
time Commands to get and set system time.
uuid Get the system UUID
version Commands to get version information.
welcomemsg Commands to get and set the welcome banner for DCUI.