Docker Swarm volumes

Containers are ephemeral. Containers live entirely in memory, so even if the container is set up with automatic restart, the new container will not have access to the data created inside of the old container. To save persistent data of Docker containers we need to create volumes that live outside of the ephemeral containers. Don’t […]

Kubernetes volumes

To understand the types of available volumes read the official Kubernetes documentation on Volumes The official documentation on Kubernetes Persistent Volume and Persistent Volume Claim is at Persistent Volumes Migrating to CSI drivers from in-tree plugins Kubernetes moves away from in-tree plugins, that had to be checked into the Kubernetes code repository to out-of-tree volume […]

Resources to learn Kubernetes

This is a great five part blog series on Kubernetes and a post on volumes by Sebastian Caceres. I recommend reading it even before the official Kubernetes tutorial to get a great overview of how Kubernetes really works. How does it work? Kubernetes: Episode 1 – Kubernetes general architecture How does it work? Kubernetes: Episode […]

Kubernetes commands

kubectl get – list resources kubectl describe – show detailed information about a resource kubectl logs – print the logs from a container in a pod kubectl exec – execute a command on a container in a pod List existing pods Get detailed information on the pods Start a proxy to access the containers within the pod Get the […]

Install missing commands on Linux distributions

On some lean systems, mostly in Docker containers, some important commands are not readily available. The table below shows the command to install them. To get the name of the Linux distribution execute To find the package that contains the command, install apt-file Update the file package mapping database Search for the command at the […]

How to duplicate a Windows server that is attached to the Windows Domain

When a Windows server is attached to a Domain only one instance of it can run at a time. To be able to duplicate the server and start a second instance of it Create an image of the server Remote into the server Make sure there is a local administrator account that you can log […]

Unable to insert the virtual optical disk in an Ubuntu virtual machine

When you try to install a new version of the VirtualBox Guest Addition on an Ubuntu virtual machine you may get the error message Unable to insert the virtual optical disk C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso into the machine Ubuntu 64. Could not mount the media/drive ‘C:\Program Files\Oracle\VirtualBox\VBoxGuestAdditions.iso’ (VERR_PDM_MEDIA_LOCKED). Result Code: E_FAIL (0x80004005) Component: ConsoleWrap Interface: IConsole {872da645-4a9b-1727-bee2-5585105b9eed} […]

Raw-mode is unavailable courtesy of Hyper-V error in VirtualBox

For VirtualBox to be able to start virtual machines, Hyper-V has to be turned off in Windows 10. If you get the error message when you try to launch a virtual machine in VirtualBox Raw-mode is unavailable courtesy of Hyper-V Check the Hyper-V setting Open a command prompt as an administrator, Execute the command: bcdedit […]