Dive into Openstack

Objective

Dive into Openstack

Keywords

• KVM, Openstack, Virtualization, Nova, Glance

Environment

• Ubuntu 16.04 on Virtualbox for macOS

KVM

• Kernel-based Virtual Machine
• kvm.ko for CPU & RAM mgmt
• Linux kernel & Qemu for I/O virtualization e.g. Storage & Networking
• Libvirt for managing Hypervisor like KVM, VirtualBox, Xen; Openstack uses Libvirt at its bottom
• Libvirt componments: libvirtd as daemon, API, virsh as CLI
• Virt-manager: GUI tool

KVM management

• egrep -o ‘(vmx|svm)’ /proc/cpuinfo
• service libvirt-bin status
• virt-manager
• virsh list // list virtual machines
• sudo apt-get install qemu-kvm qemu-system libvirt-bin virt-manager bridge-utils vlan
• sudo apt-get install xinit gdm kubuntu-desktop

vCPU

• Every virtual CPU is a thread of process qemu-kvm
• vCPU can be overcommit, but need to be tested for performance

Virtual memory

• Virtual Addres -> Physical Address on VM -> Machine Address on bare metal
• vMem can be overcommit, but need to be tested for performance

Stoage virtualization

• Virtualization through Storage pool & volume
• Default storage pool: /var/lib/libvirt/images/
• A file is basically a volume

Network virtualization

VM0 (vnet0), VM1 (vnet1) — br0 (Linux bridge) — eth0 (Physical)

• Create bridge br0 and mount physical eth0 on br0 auto lo iface lo inet loopback

auto eth0 iface eth0 inet manual

auto br0 iface br0 inet dhcp bridge_stp off bridge_waitport 0 bridge_fd 0 bridge_ports eth0

• brctl show

• ps -ef|grep dnsmasq // DHCP service, allocated IP could be found in config file: /var/lib/libvirt/dnsmasq/default.leases

• virsh list -all

• virsh domiflist VM1

• Linux bridge Working on TCP/IP 2nd layer, as a hub or switch, to be connected by devices in the network

• virbr0 A default bridge created by KVM, to provide NAT services for vnet devices connected to the bridge

• VLAN Virtual Local Area Network

  • Work on layer 2, meaning arp can not cross the border of LAN, IP on 3rd layer could be communicated using a router
  • Switch with VLAN feature is required to implement VLAN. It can provide multiple LANs through its ports
  • Two modes of port configuration: Access and Trunk

Tools

• vmdiff // to compare files