An image is what is used by the Docker and QEMU drivers to setup the build environment for build execution. A user can upload custom images to use for their builds. Right now Djinn CI only supports the uploading of QEMU driver images.
Note: Since the Docker driver uses Docker Hub to download images, you can specify any image for this driver to use, and as long as the Djinn Server can talk to the Docker Hub, that image will be downloaded and used.
Djinn CI comes with a set of default images for the QEMU driver that can be used. The full list of these images can be found on the Djinn CI image server.
Images are created from the Images link the dashboard's sidebar, and by clicking the Create button in the top right hand corner.
Images for the QEMU driver are expected to be QCOW2 (v3) image file. It is expected for the
root user to have no password and for SSH access to be configured for the
Images can be grouped in a namespace for use by other users who have access to that same namespace. If the namespace being specified does not exist during image creation then it will be created on the fly.
First create create a new image file using the
qemu-img command with the format of
qcow2. We recommend keeping the size of this image smaller than 20GB.
$ qemu-img create -f qcow2 my-image.qcow2 10G
With this image created you can now install an operating system of your choice, and prepare it for use in Djinn CI as a custom image.
$ qemu-system-x86_64 -m 4096 \ -cdrom ubuntu.iso \ -net nic,model=virtio \ -net user \ -drive file=my-image.qcow2,media=disk,if=virtio
Once the operating has been installed we can go about configuring the image for use. The QEMU driver in Djinn CI uses a passwordless
root user to connect to the machine to perform jobs, so we need to ensure that the
root user has no password.
$ passwd -d root
Next, we need to configure the SSH server to allow for a root login, and to allow password authentication. Below is the typical SSH configuration used by the base images provided by Djinn CI.
PermitRootLogin yes PasswordAuthentication yes PermitEmptyPasswords yes PubkeyAuthentication no ChallengeResponseAuthentication no GSSAPIAuthentication no UsePAM no UseDNS no AcceptEnv * PermitUserEnvironment yes Subsystem sftp internal-sftp
Once an image has been uploaded you can use it by simply specifying its name in the build manifest,
driver: type: qemu image: my-image