Pandas is good at handling large volumes of data. However there is always an upper limit. What if you are looking for summary statistics for an extremely large data set and your narrowest window of analysis is known. Do you want to look at all the data? Probably not. Narrowest…

Its been some time since I wrote the Kubernetes Resource Management Deep dive. In this post I wanted to reduce Kubernetes to it very bare bones ignoring all the scaffolding introduced by various controllers and higher level abstractions and focus on the building blocks with specific focus on how networking…

invocation ./lkvm run --kernel bzImage --disk rootfs.ext4 --debug --network mode=user Inside the VM ip addr add 192.168.33.2/24 dev enp0s0 ip link set up enp0s0 ip route add default via 192.168.33.1 Now you can reach the host Implementation Setup 837 ndev = calloc(1, sizeof(struct net_dev)); 841…

Multi-Point GRE Tunnels Typically VxLAN is used to setup a point to multi-point overlay networks. However GRE also offers a similar capability which is often not heavily used. This document calls out how to setup an effient overlay mesh network to link up multiples sits together using multi point GRE tunnels. Setup The setup…

But default in linux you can figure out how many times and for what reasons there is a VM Exit from a VM into the kvm kernel module. However given the ubiquity of vhost and the ability of kvm to emulate most device models directly in the kernel, most of…

Overview QEMU supports migration of a virtual machine across machine over the network. It also has the capability to save the state of a virtual machine and resume from that state. It is described in detail in https://www.linux-kvm.org/page/Migration This capability can be leveraged to create an instant resume virtual machine image…

Example program Say a program has opened a raw socket. How do you know it has it open + int sock_r; + struct ifreq ifrr; + size_t if_name_len=strlen("dummy0"); + struct sockaddr_ll…

Kernel Build Build the kernel with ACPI debug enabled as described in https://www.kernel.org/doc/Documentation/acpi/debug.txt tl;dr ACPI debug output is globally enabled by CONFIG_ACPI_DEBUG. If this config option is turned off, the debug messages are not even built into the kernel. When CONFIG_ACPI_DEBUG=y, you can select the component and level of messages you're interested…

Here the vfio-pci device is passed in into the L1 VM The L1 VM is setup with kernel_irqchip=split The L0 exposes a virtual IOMMU to the L1 VM qemu-system-x86_64 \ -machine q35,accel=kvm,kernel_irqchip=split \ -enable-kvm \ -bios OVMF.fd \…