Docker
Contents
Manage VMs with docker-machine
Introduction
Install software
Create machines
Create the KVM netwrok
Before a new machine can be created with the docker-machine command, the proper KVM virtual network must be created.
See How to create KVM networks for details.
Create machine
Machine can be created with the docker-machine create command. Most simple usage:
docker-machine create -d <hybervisor driver name> --<hypervisor options> <>
- -d: hypervisor driver. Default value: "virtalbox". For KVM use: "kvm".
- --kvm-network: The name of the kvm virtual network that we would like to use. If this is not set, the new machine will be connected to the "default" KVM virtual network.
Note
Even with the --kvn-network parameter provided, two new interfaces are created for every new VM.
- one for the virtual network, described with the --kvm-network parameter
- docker-machines will create a second, isolated virtual network called "docker-machines", that the new VM is also connected to
# docker-machine create -d kvm --kvm-network "docker-network" manager Running pre-create checks... Creating machine... (manager) Copying /root/.docker/machine/cache/boot2docker.iso to /root/.docker/machine/machines/manager/boot2docker.iso... Waiting for machine to be running, this may take a few minutes... Detecting operating system of created instance... Waiting for SSH to be available... Detecting the provisioner... Provisioning with boot2docker... Copying certs to the local machine directory... Copying certs to the remote machine... Setting Docker configuration on the remote daemon... Checking connection to Docker... Docker is up and running! To see how to connect your Docker Client to the Docker Engine running on this virtual machine, run: docker-machine env manager
Tip
The machine is created under /USER_HOME/.docker/machine/machines/<machine_name> directory
If the new VM was created with virtualbox driver, the VirtualBox graphical interface must be started with the same user, that the VM was created with, and the VirtualBox will discover the new VM automatically
Check what was created
Interface list on the host
# ifconfig
eno1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.0.105 netmask 255.255.255.0 broadcast 192.168.0.255
....
virbr1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.42.1 netmask 255.255.255.0 broadcast 192.168.42.255
...
virbrDocker: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.123.1 netmask 255.255.255.0 broadcast 192.168.123.255
inet6 2001:db8:ca2:2::1 prefixlen 64 scopeid 0x0<global>
...
On the host, upon the regular interfaces, we can see the two bridges for the two virtual networks:
- virbrDocker: That is the virtual network that we created in libvirt. This is connected to the host network with NAT. We assigned these IP addresses, when we defined the network.
- virbr1: That is the host-only virtual network that was created out-of-the-box. This one has no internet access.
Interface list of the new VM
You can log in to the newly created VM with the docker-machine ssh <machine_name> command
# docker-machine ssh manager
## .
## ## ## ==
## ## ## ## ## ===
/"""""""""""""""""\___/ ===
~~~ {~~ ~~~~ ~~~ ~~~~ ~~~ ~ / ===- ~~~
\______ o __/
\ \ __/
\____\_______/
_ _ ____ _ _
| |__ ___ ___ | |_|___ \ __| | ___ ___| | _____ _ __
| '_ \ / _ \ / _ \| __| __) / _` |/ _ \ / __| |/ / _ \ '__|
| |_) | (_) | (_) | |_ / __/ (_| | (_) | (__| < __/ |
|_.__/ \___/ \___/ \__|_____\__,_|\___/ \___|_|\_\___|_|
Boot2Docker version 18.05.0-ce, build HEAD : b5d6989 - Thu May 10 16:35:28 UTC 2018
Docker version 18.05.0-ce, build f150324
Check the interfaces of the new VM:
docker@manager:~$ ifconfig
docker0 inet addr:172.17.0.1 Bcast:172.17.255.255 Mask:255.255.0.0
...
eth0 inet addr:192.168.123.195 Bcast:192.168.123.255 Mask:255.255.255.0
...
eth1 inet addr:192.168.42.118 Bcast:192.168.42.255 Mask:255.255.255.0
- eth0:192.168.123.195 - Interface to the new virtual network (docker-network) created by us. this network has public internet connection
- eth1:192.168.42.118 - This connect to the dynamically created host-only virtual network. Just for VM-to-VM communication
- docker0:172.17.0.1 -
Routing table
All the packages that ment to go to the docker VMs are routed to the bridges # route Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface ... 192.168.42.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr1 <<<<this 192.168.123.0 0.0.0.0 255.255.255.0 U 0 0 0 virbrDocker <<<this