Making a KubeVirt image

Making a KubeVirt image

We now have Kubevirt installed and the first VM running, but this VM is not what we want, we now want to customize the image

Kubernetes version 1.28.2

1. Preparation of disk files

OpenEuler's qcow2 file download address

I'm building the openeuler VM here, and I can download the qcow2 file directly from the major mirror sites, and it's a zip file after downloading, so we need to decompress it.

[root@master ~]# wget /openeuler/openEuler-22.03-LTS-SP4/virtual_machine_img/x86_64/openEuler-22.03-LTS-SP4-x86_64.
[root@master ~]# xz -d openEuler-22.03-LTS-SP4-x86_64.

This way a disk file is ready for us, but of course there are other ways to get it, such as creating a virtual machine through KVM and taking the disk file out, or getting the qcow2 file through openstack

2. Writing the Dockerfile

We need to pass this disk file inside the container image

[root@master ~]# mkdir -p kubevirt/images
[root@master ~]# cd kubevirt/images
[root@master images]# cp ~/openEuler-22.03-LTS-SP4-x86_64.qcow2 .
[root@master images]# ls
openEuler-22.03-LTS-SP4-x86_64.qcow2

file in this place, and then we start writing the dockerfile

FROM openeuler/openeuler:22.03
ADD openEuler-22.03-LTS-SP4-x86_64.qcow2 /disk/openEuler-22.03-LTS-SP4-x86_64.qcow2

Just write these 2 lines and start building the image

3. Mirroring

[root@master images]# docker build -t openeuler2203-sp4:v1 .

Next wait for the build to complete

4. Upload mirrors to the repository (optional)

If you don't have a private mirror repository, this step can be left out and you can just export the mirror and import it using ctr (more on that in a minute)

We now need to upload the image to the private repository, so we have to change the image tag first

[root@master images]# docker tag openeuler2203-sp4:v1 /openeuler2203-sp4:v1
[root@master images]# docker push /openeuler2203-sp4:v1

You have to log in before you can push the image, just log in on your own, and the image will be uploaded here.

5. Export mirrors

If you don't have a private repository, do this step

[root@master images]# docker save -o  openeuler2203-sp4:v1
[root@master images]# ctr -n  image import  

Once the import is complete we can use this image to boot the VM, next we prepare a boot template for the VM

6. Virtual machine yaml file

[root@master images]# vim


apiVersion: /v1
kind: VirtualMachine
metadata:
  name: openeuler
spec:
  running: false
  template:
    metadata:
      labels:
        /domain: openeuler
    spec:
      domain:
        devices:
          disks:
          - name: rootfs
            disk:
              bus: virtio
          - name: cloudinit
            disk:
              bus: virtio
          interfaces:
          - name: default
            bridge: {}
        resources:
          requests:
            memory: 1Gi
          limits:
            memory: 1Gi
      networks:
      - name: default
        pod: {}
      volumes:
        - name: rootfs
          containerDisk:
            image: openeuler2203-sp4:v1
             # This is where you fill in the name of the disk file you just sent in.
            path: /disk/openEuler-22.03-LTS-SP4-x86_64.qcow2
        #- name: cloudinit
        # cloudInitNoCloud:
        # userData: |-
        # #cloud-config
        # password: openeuler
        # chpasswd: { expire: False }
        # ssh_pwauth: True
        # packages:
        # - nginx
        # runcmd:
        # - systemctl enable nginx
        # - systemctl start nginx

The last paragraph is cloud-init, but openeuler does not have this service installed by default, so it is useless to write it, replace it with another system is completely OK, here's the cloud-init is to allow him to perform some personalized operations, I am here is to write the installation of nginx and change the password of the root, which does not take effect in my case, so I commented on the

7. Starting the virtual machine

We have the image ready as well as the yaml file, so we can now start booting the virtual machine

[root@master images]# kubectl apply -f 
[root@master kubevirt]# kubectl get vms
NAME        AGE     STATUS    READY
openeuler   41s     Stopped   False

Next we start this virtual machine

[root@master kubevirt]# virtctl start openeuler
VM openeuler was scheduled to start
[root@master kubevirt]# kubectl get vms
NAME        AGE     STATUS    READY
openeuler   1m17s   Running   True

Now that he's running, we can connect in.

[root@master kubevirt]# virtctl console openeuler
Successfully connected to openeuler console. The escape sequence is ^]

openeuler login: root
Password: 

Authorized users only. All activities may be monitored and reported.


Welcome to 5.10.0-216.0.0.115.oe2203sp4.x86_64

System information as of time: 	Tue Jul 23 09:32:59 AM UTC 2024

System load: 	0.38
Memory used: 	3.7%
Swap used: 	0.0%
Usage On: 	4%
IP address: 	10.244.219.127
Users online: 	1


[root@openeuler ~]#

The default password for this image isopenEuler12#$

Or connect directly via ssh, his IP address is 10.244.219.127

[root@master kubevirt]# ssh [email protected]

Authorized users only. All activities may be monitored and reported.
[email protected]'s password: 

It's possible to connect.

8. Error booting virtual machine

[root@master kubevirt]# kubectl apply -f  
Warning: /v1alpha3 is now deprecated and will be removed in a future release.
The request is invalid: [2]: HostDisk feature gate is not enabled

If you're getting this error it's because the hostDisk feature is not turned on, so let's turn it on.

[root@master kubevirt]# kubectl edit -n kubevirt kv kubevirt 


spec:
  configuration:
    developerConfiguration:
      featureGates:
      - HostDisk

Find this paragraph, change the content to this, then save and exit to resolve the error