README
¶
virtlet 
Virtlet is a Kubernetes runtime server which allows you to run VM workloads, based on QCOW2 images.
It is possible to run Virtlet by following the instructions from either Running local environment or Deploy using DaemonSets documents. There's also separate document describing the process of installing Virtlet on real clusters.
See here for the description of Virtlet architecture.
Community
You can join #virtlet channel on Kubernetes Slack (register at slack.k8s.io if you're not in k8s group already). Both the users and developers are welcome!
Getting started with Virtlet
To try out Virtlet follow the instructions from Running local environment and try out examples documents.
Virtlet introduction video
You can watch and listen to Virtlet demo video that was recorded on Kubernetes Community Meeting here.
Command line interface
Virtlet comes with a helper tool,
virtletctl, that helps managing the VM pods. The binaries will be available for Linux and Mac OS X in the Releases section starting from Virtlet 1.0. For now, you can build it using the build tool.
After build/cmd.sh copy you'll get _output/virtletctl (for Linux x86_64) and _output/virtletctl.darwin (for Mac OS X). If you're using Kubernetes 1.9, you can install virtletctl as a kubectl plugin:
./virtletctl install
After that you can use kubectl plugin virt instead of virtletctl (plugin subcommand will not be necessary when kubectl plugins become stable):
kubectl plugin virt ssh cirros@cirros-vm -- -i examples/vmkey
Virtlet usage demo
You can watch sample usage session under this link.
You can also give Virtlet a quick try using our demo script (requires Docker 1.12+):
wget https://raw.githubusercontent.com/Mirantis/virtlet/master/deploy/demo.sh
chmod +x demo.sh
# './demo.sh --help' displays the description
./demo.sh
The demo will start a test cluster, deploy Virtlet on it and then boot a CirrOS VM there. You may access sample nginx server via curl http://nginx.default.svc.cluster.local from inside the VM. To disconnect from VM, press Ctrl-D. After the VM has booted, you can also use virtletctl tool to connect to its SSH server:
virtletctl ssh cirros@cirros-vm -- -i examples/vmkey [command...]
By default, CNI bridge plugin is used for cluster networking. It's also possible to override this with calico, flannel or weave plugin, e.g.:
CNI_PLUGIN=flannel ./demo.sh
There's also an option to deploy Virtlet on master node of the DIND
cluster, which can be handy e.g. if you don't want to use worker nodes
(i.e. start the cluster with NUM_NODES=0):
VIRTLET_ON_MASTER=1 ./demo.sh
The demo script will check for KVM support on the host and will make Virtlet use KVM if it's available on Docker host. If KVM is not available, plain QEMU will be used.
The demo is based on kubeadm-dind-cluster project. Docker btrfs storage driver is currently unsupported. Please refer to kubeadm-dind-cluster documentation for more info.
You can remove the test cluster with ./dind-cluster-v1.9.sh clean when you no longer need it.
External projects using Virtlet
There are some external projects using Virtlet already. One interesting usecase is that of MIKELANGELO project that runs OSv unikernels on Kubernetes using Virtlet. Unikernels are special case of VMs that are extremely small in size (20MB or so) and can only run a single process each. Nevertheless, Virtlet has no problems handling them on Kubernetes as demonstrated in this video. Microservice Demo is available here.
Need any help with Virtlet?
If you will encounter any issue when using Virtlet please look into our issue tracker on github. If your case is not mentioned there - please fill new issue for it. In case of any questions you may also use #virtlet channel on Kubernetes Slack.
Contributing
Virtlet is an open source project and any contributions are welcomed. Look into Contributing guidelines document for our guidelines and further instructions on how to set up Virtlet development environment.
Licensing
Unless specifically noted, all parts of this project are licensed under the Apache 2.0 license.
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