RUNNING VIRTUAL MACHINES ON KUBERNETES Roman Mohr & Fabian - - PowerPoint PPT Presentation

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RUNNING VIRTUAL MACHINES ON KUBERNETES Roman Mohr & Fabian - - PowerPoint PPT Presentation

Aug 16, 2022 397 likes •784 views

RUNNING VIRTUAL MACHINES ON KUBERNETES Roman Mohr & Fabian Deutsch, Red Hat, KVM Forum, 2017 1 FABIAN DEUTSCH ROMAN MOHR Fedora user and former oVirt and KubeVirt Contributor package maintainer Working at Red Hat oVirt and KubeVirt

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RUNNING VIRTUAL MACHINES ON KUBERNETES

Roman Mohr & Fabian Deutsch, Red Hat, KVM Forum, 2017

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FABIAN DEUTSCH

Fedora user and former package maintainer

  • Virt and KubeVirt Contributor

Working at Red Hat

ROMAN MOHR

  • Virt and KubeVirt Contributor

Working at Red Hat fabiand@redhat.com @dummdida fabiand https://dummdida.tumblr.com rmohr@redhat.com @rfenkhuber rmohr

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VIRTUALIZATION IS

  • OMNIPRESENT. TODAY.

(drome, CC BY-NC 2.0) 3

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CONTAINERS AS WELL.

(davehamster, CC BY 2.0) 4

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CONTAINERS LOOK, TASTE, AND SMELL THE SAME - JUST BETTER

"Versatile, scalable, hyped, community driven, devops, …" Take this with a grain of salt.

(colinwarren, CC BY-NC 2.0) 5

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"HOW DO WE GET THERE?" "HOW CAN I REPLACE MY VMS WITH CONTAINERS? HOW!?"

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ARE THEY REALLY SUBSTITUTES? IS THE ONE LIKE THE OTHER?

Technology? Features? Feeling? Tools? Requirements?

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⇝ ⇝ IT DEPENDS

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NOT YET? "NEVER"?

Yes No

COOL

Replace?

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MIGRATION

If workloads can be moved to containers, then it's a migration

CONVERGENCE

If not, then we still want convergence

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Yes No Replace?

XX% YY% BOTH.

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Yes

MIGRATION PATH?

Replace?

DOUBLED INFRASTRUCTURE?

No

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Management Plane Storage Network … Virtual Machines Management Plane Storage Network … Containers

2X INFRASTRUCTURE?

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Virtualization and containers

( ) giphy 10

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KUBEVIRT

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CONTAINERS & VIRTUAL MACHINES

  • n the same infrastructure.

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Management Plane Storage Network … Virtual Machines Containers

KEEP YOUR VMS …

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Management Plane Storage Network … Virtual Machines Containers

… TRANSITION WHAT YOU NEED …

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Management Plane Storage Network … Virtual Machines Containers

… AND STICK TO VMS AS NEEDED.

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WOOT?

Tell me more.

( ) giphy 13

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Kubernetes Storage Network … Virtual Machines Containers

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Kubernetes Storage Network … Virtual Machines Containers + KubeVirt

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HOW DOES KUBEVIRT INTEGRATE WITH KUBERNETES?

The Details.

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kind: Pod metadata: name: nginx labels: name: nginx spec: containers:

  • name: nginx

image: nginx:latest ports:

  • containerPort: 80

nodeSelector: cpu: fast status: phase: Running

KUBERNETES API

“A pod (as in a pod of whales or pea pod) is a group of one or more containers (such as Docker containers), with shared storage/network, and a specification for how to run the containers.” *

* https://kubernetes.io/docs/concepts/workloads/pods/pod/#what-is-a-pod

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HOW ABOUT TREATING A POD AS A VM?

Add device details as annotations. Modify the container runtime on every node. Deal with the fact that there are two Pods when you do migrations. Implement as much functionality as possible from the Kubelet, since there is not way to distinguish from

  • utside what your VM Pod supports, compared to a

normal Pod. Are we talking about a VM Pod or a Pod?

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HOW ABOUT ADDING AN EXPLICIT VIRT API?

Allows a proper Virtual Machine Specification We can ship KubeVirt as a pue add-on. No Node modifications are necessary. No matter, how much Pods are necessary to perform a migration, we have one single entrypoint to the Virtual Machine. Reuse all of the kubelet and Pod Spec functionality, by running a Virtual Machine inside the Pod Talk about VMs when they are VMs, talk about Pods when they are Pods.

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kind: VirtualMachine metadata: name: testvm spec: domain: devices: type: PersistentVolumeClaim device: disk source: name: myVolumeClaim nodeSelector: cpu: fast status: phase: Running

KUBEVIRT API

We have the typical Pod like structure: Metadata section Specification section Typical Pod features like nodeSelector affinity Status section Behind the scene a Pod is created, scheduled and we make sure that the VM starts correctly inside.

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kind: VirtualMachine metadata: name: testvm spec: domain: devices: graphics:

  • type: spice

consoles:

  • type: pty

Typical Pod commands: kubectl create -f mypodspec.yaml kubectl delete mypod kubectl exec mypod -it /bin/bash Typical VirtualMachine commands: kubectl create -f myvmspec.yaml kubectl delete testvm kubectl plugin virt console testvm kubectl plugin virt spice testvm

TYPICAL KUBECTL FEELING

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Documentation

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kind: Migration metadata: generateName: my-migration spec: nodeSelector: kubevirt.io/hostname: node1 selector: name: testvm status: phase: Succeeded

MIGRATIONS

Backed by a controller: On object create, schedules a new Pod On successful Pod start, it triggers the migration At the end of the migration the object is moved to a final state Always one VirtualMachine object you reference The objects Migration with VirtualMachine provide a consistent entry point to anything VirtualMachine related, like the Pod does for Kubernetes.

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API CHALLENGES

Feature wise comparable to domxml Certain features are node specific - they need to be abstracted Needs to be married with Kubernetes concepts (pv, networks) Needs additional data for cluster-only features like scheduling

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INTEGRATION CHALLENGES

Properly integrate the VirtualMachine lifecycle in a Pod lifecycle. Disks Networking qemu with libvirt in a Pod cgroups and Namespaces Migrations on top of Kubernetes

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ADDITIONAL FEATURES

VirtualMachineReplicaSet Cloud Provider Nested Kubernetes Nodes Cloud Init Console/Spice access More to come ...

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PILLARS AND EFFECTS.

libvirt, … everything in pods New resource type for VMs to manage VMs VMs live inside pods Operator pattern Native Kubernetes add-on with VM functionality Declarative, like everything else Kubernetes' infrastructure is leveraged API server ⇝ ⇝ ⇝ ⇝

(tabor-roeder, CC BY 2.0) 27

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$ minikube start --vm-driver kvm --network-plugin cni $ git clone https://github.com/kubevirt/demo.git $ cd demo $ bash run-demo.sh

TRY (WITH

) MINIKUBE

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$ bash run-mini-demo.sh # Deploying KubeVirt ... vm "testvm" created Waiting for KubeVirt to be ready ... Waiting for KubeVirt to be ready ... Waiting for KubeVirt to be ready ... # KubeVirt is now ready. Try: # $ kubectl get vms $ kubectl get vms NAME KIND testvm VM.v1alpha1.kubevirt.io $ kubectl get pods NAME READY STATUS RESTARTS AGE haproxy-723816479-wcblm 1/1 Running 1 49s iscsi-demo-target-tgtd-1270025779-nckbh 1/1 Running 0 48s libvirt-8zj1k 2/2 Running 0 48s spice-proxy-3525077118-fswn9 1/1 Running 0 47s virt-api-1956313626-t9rhj 1/1 Running 0 46s virt-controller-2251532855-tfm9f 1/1 Running 0 45s virt-handler-s7g76 1/1 Running 0 43s virt-launcher-testvm-----q05vh 1/1 Running 0 38s virt-manifest-1665692876-cs8wp 2/2 Running 0 42s $ kubectl exec -it libvirt-8zj1k bash Defaulting container name to libvirtd. Use 'kubectl describe pod/libvirt-8zj1k' to see all of the containers in this pod. # virsh list Id Name State

  • 1 default_testvm running

# exit 28 . 2

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@kubevirt kubevirt Thank you. Learn and contribute at http://kubevirt.io

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