constellation/docs/local-image-testing.md

Local image testing with QEMU

To build our images we use the CoreOS-Assembler (COSA). COSA comes with support to test images locally. After building your image with make coreos you can run the image with make run.

Our fork adds extra utility by providing scripts to run an image in QEMU with a vTPM attached, or boot multiple VMs to simulate your own local Constellation cluster.

Begin by starting a COSA docker container

docker run -it --rm \
    --entrypoint bash \
    --device /dev/kvm \
    --device /dev/net/tun \
    --privileged \
    -v </path/to/constellation-image.qcow2>:/constellation-image.qcow2 \
    ghcr.io/edgelesssys/constellation-coreos-assembler

Run a single image

Using the run-image script we can launch a single VM with an attached vTPM. The script expects an image and a name to run. Optionally one may also provide the path to an existing state disk, if none provided a new disk will be created.

Additionally one may configure QEMU CPU (qemu -smp flag, default=2) and memory (qemu -m flag, default=2G) settings, as well as the size of the created state disk in GB (default 2) using environment variables.

To customize CPU settings use CONSTELL_CPU=[[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,cores=cores][,threads=threads]
To customize memory settings use CONSTELL_MEM=[size=]megs[,slots=n,maxmem=size]
To customize state disk size use CONSTELL_STATE_SIZE=n

Use the following command to boot a VM with 2 CPUs, 2G RAM, a 4GB state disk with the image in /constellation/coreos.qcow2. Logs and state files will be written to /tmp/test-vm-01.

sudo CONSTELL_CPU=2 CONSTELL_MEM=2G CONSTELL_STATE_SIZE=4 run-image /constellation/coreos.qcow2 test-vm-01

The command will create a network bridge and add the VM to the bridge, so the host may communicate with the guest VM, as well as allowing the VM to access the internet.

Press Ctrl+A X to stop the VM, this will remove the VM from the bridge but will keep the bridge alive.

Run the following to remove the bridge.

sudo delete_network_bridge br-constell-0

Create a local cluster

Using the create-constellation script we can create multiple VMs using the same image and connected in one network.

The same environment variables as for run-image can be used to configure cpu, memory, and state disk size.

Use the following command to create a cluster of 4 VMs, where each VM has 3 CPUs, 4GB RAM and a 5GB state disk. Logs and state files will be written to /tmp/constellation.

sudo CONSTELL_CPU=3 CONSTELL_MEM=4G CONSTELL_STATE_SIZE=5 create-constellation 4 /constellation/coreos.qcow2

The command will use the run-image script launch each VM in its own tmux session. View the VMs by running the following

sudo tmux attach -t constellation-vm-<i>