Kubernetes uses containers managed by container engines like Docker. It separates containers from the host machine using namespaces and cgroups for isolation. Docker containers share the host kernel and use aufs for the union filesystem. Virtual machines (VMs) run a full guest operating system with virtualization provided by hypervisors like KVM/QEMU. Containers are more lightweight than VMs as they share the host kernel and have smaller base images and faster launch times and resource usage.

1. Kubernetes 架構與虛擬化之
差異
Senior Solution Architect Bean

2. Agenda
• Container connectiuon with Kubernetes
• Docker Virtualization
• VM Virtualization
• Comparison

3. Kubernetes Architecture
• Master
– apiserver
– scheduler
• Minion
– kube-proxy
– kubelet
– container
• ETCD

4. Container = Docker ?

5. Kubernetes support Containers
• Windows Server Container (windows kernel)
• Hyper-V Container (window kernel)
• Docker Container (linux kernel)
...

6. Early Docker Architecture
APP A
Bins/Libs
APP B
Bins/Libs
Container Engine
HostOS
Hardware
● Based on LXC (Linux Container)
● LXC appears from kernel 2.6.29
● LXC driver must be activated

7. Kernel

8. LXC Sample
Under AWS Ubuntu 16.04 HVS Virtaul Machine
• sudo apt-get install lxc lxc-templates wget bridge-utils
• sudo lxc-create -n Name -t SampleName (create container)
– ex: sudo lxc-create -n ubuntu_lxc -t ubuntu
• sudo lxc-start -n ubuntu_lxc -d (start container)
• sudo lxc-console -n ubuntu_lxc (login container)
• sudo lxc-ls (list containers)
• sudo lxc-cgroup -n ubuntu_lxc memroy.limit_in_bytes 256M

9. Docker Visulization

10. Container use Kernel API
• namespaces allows us to isolate processes from each
other(process, network, messaging, file system,
hostname)
• cgroups allows us to limit resource utilization
• aufs implements a union mount
• linux bridge bridges each container

11. Docker Flow
Docker Run
Flow

12. Type2 VM Visualization
APP A
Bins/Libs
APP B
Bins/Libs
Guest
OS
Hypervisor
Host OS
Guest
OS
Hardware

13. KVM-QEMU Hypervisor

14. Comparison
APP A
Bins/Libs
APP B
Bins/Libs
Libcontainer
HostOS
Hardware

15. Summary
• Kubernetes vs Docker
• Container vs VM (kernel)
– base image size small
– launch time short
– resource(cpu, memory) usage small