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Getting started with Docker

In this tutorial, we'll run matchbox on your Linux machine with Docker to network boot and provision a cluster of QEMU/KVM Container Linux machines locally. You'll be able to create Kubernetes clusters, etcd3 clusters, and test network setups.

Note: To provision physical machines, see network setup and deployment.

Requirements

Install the package dependencies and start the Docker daemon.

$ # Fedora
$ sudo dnf install docker virt-install virt-manager
$ sudo systemctl start docker

$ # Debian/Ubuntu
$ # check Docker's docs to install Docker 1.8+ on Debian/Ubuntu
$ sudo apt-get install virt-manager virtinst qemu-kvm

Clone the matchbox source which contains the examples and scripts.

$ git clone https://github.com/coreos/matchbox.git
$ cd matchbox

Download CoreOS Container Linux image assets referenced by the etcd3 example to examples/assets.

$ ./scripts/get-coreos stable 1576.5.0 ./examples/assets

For development convenience, add /etc/hosts entries for nodes so they may be referenced by name.

# /etc/hosts
...
172.17.0.21 node1.example.com
172.17.0.22 node2.example.com
172.17.0.23 node3.example.com

Containers

Run the matchbox and dnsmasq services on the docker0 bridge. dnsmasq will run DHCP, DNS and TFTP services to create a suitable network boot environment. matchbox will serve configs to machines as they PXE boot.

The devnet convenience script can start these services and accepts the name of any example cluster in examples.

$ sudo ./scripts/devnet create etcd3

Inspect the logs.

$ sudo ./scripts/devnet status

Take a look at the etcd3 groups to get an idea of how machines are mapped to Profiles. Explore some endpoints exposed by the service, say for QEMU/KVM node1.

Manual

If you prefer to start the containers yourself, instead of using devnet,

$ sudo docker run -p 8080:8080 --rm -v $PWD/examples:/var/lib/matchbox:Z -v $PWD/examples/groups/etcd3:/var/lib/matchbox/groups:Z quay.io/coreos/matchbox:latest -address=0.0.0.0:8080 -log-level=debug
$ sudo docker run --name dnsmasq --cap-add=NET_ADMIN -v $PWD/contrib/dnsmasq/docker0.conf:/etc/dnsmasq.conf:Z quay.io/coreos/dnsmasq -d

Client VMs

Create QEMU/KVM VMs which have known hardware attributes. The nodes will be attached to the docker0 bridge, where Docker containers run.

$ sudo ./scripts/libvirt create

You can connect to the serial console of any node (ctrl+] to exit). If you provisioned nodes with an SSH key, you can SSH after bring-up.

$ sudo virsh console node1
$ ssh core@node1.example.com

You can also use virt-manager to watch the console.

$ sudo virt-manager

Use the wrapper script to act on all nodes.

$ sudo ./scripts/libvirt [start|reboot|shutdown|poweroff|destroy]

Verify

The VMs should network boot and provision themselves into a three node etcd3 cluster, with other nodes behaving as etcd3 gateways.

The example profile added autologin so you can verify that etcd3 works between nodes.

$ systemctl status etcd-member
$ etcdctl set /message hello
$ etcdctl get /message

Clean up

Clean up the containers and VM machines.

$ sudo ./scripts/devnet destroy
$ sudo ./scripts/libvirt destroy

Going further

Learn more about matchbox or explore the other example clusters. Try the k8s example to produce a TLS-authenticated Kubernetes cluster you can access locally with kubectl.