Kubernetes Architecture 101 – Mind Map

I have been spending some time on K8s, digging deep down to understand the components involved and how they play role in running a successful application on K8s Architecture.

Learning for me is always into basics, once you are comfortable with it then any top application running will be easy to understand, will be easy to troubleshoot, will be easy to enhance.

Previous post was a very high level K8s mind map and here I am posting another 101 Mind map for it’s Architecture.

K8s Architecture Mind Map

Kubernetes 101 – Mind Map

I have played with Kubernetes in past, but it has been years and was just to get started. That knowledge still stays inside me to understand discussions related to Kubernetes

Finally decided to get hands deep dirty and created this couple of days back, thought to blog it for reference and might be useful for someone getting started.

K8s Mind Map

Using command line kill/power off a virtual machine

VMWARE ESXI CLI

Using the ESXi esxcli command to power off a virtual machine

The esxcli command can be used locally or remotely to power off a virtual machine running on ESXi 5.x or later. For more information, see the esxcli vm Commands section in the vSphere Command-Line Interface Reference.

  1. Open a console session where the esxcli tool is available, either in the ESXi Shell, the vSphere Management Assistant (vMA), or the location where the vSphere Command-Line Interface (vCLI) is installed.
  2. Get a list of running virtual machines, identified by World ID, UUID, Display Name, and path to the .vmx configuration file by running this command:esxcli vm process list
  3. Power off the virtual machine from the list by running this command:esxcli vm process kill --type= [soft,hard,force] --world-id= WorldNumberNotes:
    • Three power-off methods are available. Soft is the most graceful, hard performs an immediate shutdown, and force should be used as a last resort.
    • alternate power off command syntax is: esxcli vm process kill -t [ soft,hard,force] -w WorldNumber
  4. Repeat Step 2 and validate that the virtual machine is no longer running.

Using the ESXi command-line utility vim-cmd to power off the virtual machine

  1. On the ESXi console, enter Tech Support mode and log in as root. For more information, see Tech Support Mode for Emergency Support (1003677).
  2. Get a list of all registered virtual machines, identified by their VMID, Display Name, and path to the .vmx configuration file by running this command:vim-cmd vmsvc/getallvms
  3. Get the current state of a virtual machine by running this command:vim-cmd vmsvc/power.getstate VMID
  4. Shutdown the virtual machine using the VMID found in Step 2 and run this command:vim-cmd vmsvc/power.shutdown VMIDNote: If the virtual machine fails to shut down, run this command:vim-cmd vmsvc/power.off VMID

Note: this article is for my quick reference, VMware KB reference (https://kb.vmware.com/s/article/1014165)

Scan for new SCSI drives without the need to reboot the VM – LINUX

New disk presented to the running LINUX virtual machine will not display the device into operating system unless you reboot the server.

Found another way to achieve this and thought to note it down here for my future reference.

Run the following commands:

The first command returns the SCSI host in use which in this case is host2.:

grep mpt /sys/class/scsi_host/host?/proc_name

The next command, performs a bus scan.

echo “- – -“ > /sys/class/scsi_host/host2/scan

Fdisk is used to list all the available drives on the machine.

Validate if you can view new disk:

fdisk -l

If the newly added drive is still not discovered, then unfortunately just reboot the VM.

Content Referenced article: https://www.altaro.com/vmware/managing-disk-space-linux-vm/