Boot2Docker is a lightweight Linux distribution made specifically to run Docker containers. It runs completely from RAM, is a small ~24MB download and boots in ~5s (YMMV).
- Kernel 4.1.13 with AUFS, Docker v1.9.1 - using libcontainer
- Container persistence via disk automount on
- SSH keys persistence via disk automount
Note: Boot2Docker uses port 2376, the registered IANA Docker SSL port
Boot2Docker is currently designed and tuned for development. Using it for any kind of production workloads at this time is highly discouraged.
All in one Installers for OS X and Windows
Installation using the
boot2docker management tool
How to use
boot2docker management tool leverages VirtualBox's
initialise, start, stop and delete the VM right from the command line.
$ boot2docker init
$ boot2docker up
Upgrade the Boot2docker VM image
$ boot2docker stop $ boot2docker download $ boot2docker up
If your Boot2Docker virtual machine was created prior to 0.11.1-pre1, it's recommended that you
boot2docker delete and then create a new
The main change is the addition of a
/var/lib/boot2docker/userdata.tar file that is
un-tarred into the
/home/docker directory on boot. This file contains
.ssh/authorized_keys2 files containing a public
To save and share container images, automate workflows, and more sign-up for a free Docker Hub account.
See Frequently asked questions for more details.
Boot script log
The bootup script output is logged to
/boot.log, so you can see (and
potentially debug) what happens. Note that this is not persistent between boots
because we're logging from before the persistence partition is mounted (and it
may not exist at all).
Container Port redirection
The latest version of
boot2docker sets up two network adaptors, one using NAT
to allow the VM to download images and files from the internet, and a host only
network that Docker container's ports will be exposed on.
If you run a container with an exposed port, and then use OSX's
$ boot2docker up $ eval "$(boot2docker shellinit)" $ docker run --name nginx-test -d -p 80:80 nginx $ open http://$(boot2docker ip 2>/dev/null)/ $ docker stop nginx-test $ docker rm nginx-test
eval "$(boot2docker shellinit)" sets the
DOCKER_HOST environment variable for
this shell, then the
docker run starts the webserver as a daemon, and
will then show the default page in your default web browser (using
If you want to share container ports with other computers on your LAN, you will need to set up NAT adaptor based port forwarding.
Docker daemon options
If you need to customize the options used to start the Docker daemon, you can
do so by adding entries to the
/var/lib/boot2docker/profile file on the
persistent partition inside the Boot2Docker virtual machine. Then restart the
The following example will enable core dumps inside containers, but you can specify any other options you may need.
boot2docker ssh -t sudo vi /var/lib/boot2docker/profile # Add something like: # EXTRA_ARGS="--default-ulimit core=-1" boot2docker restart
docker with TLS enabled. It auto-generates
certificates and stores them in
/home/docker/.docker inside the VM. The
boot2docker up command will copy them to
~/.boot2docker/certs on the
host machine once the VM has started, and output the correct values for
DOCKER_TLS_VERIFY environment variables.
eval "$(boot2docker shellinit)" will also set them correctly.
We strongly recommend against running Boot2Docker with an unencrypted Docker
socket for security reasons, but if you have tools that cannot be easily
switched, you can disable it by adding
DOCKER_TLS=no to your
Boot2Docker is essentially a remote Docker engine with a read only filesystem (other than Docker images, containers and volumes). The most scalable and portable way to share disk space between your local desktop and a Docker container is by creating a volume container and then sharing that to where it's needed.
One well tested approach is to use a file sharing container like
$ # Make a volume container (only need to do this once) $ docker run -v /data --name my-data busybox true $ # Share it using Samba (Windows file sharing) $ docker run --rm -v /usr/local/bin/docker:/docker -v /var/run/docker.sock:/docker.sock svendowideit/samba my-data $ # then find out the IP address of your Boot2Docker host $ boot2docker ip 192.168.59.103
Connect to the shared folder using Finder (OS X):
Connect to cifs://192.168.59.103/data Once mounted, will appear as /Volumes/data
Or on Windows, use Explorer to Connect to:
You can then use your data container from any container you like:
$ docker run -it --volumes-from my-data ubuntu
You will find the "data" volume mounted as "/data" in that container. Note that "my-data" is the name of volume container, this is shared via the "network" by the "samba" container that refers to it by name. So, in this example, if you were on OS-X you now have /Volumes/data and /data in container being shared. You can change the paths as needed.
VirtualBox Guest Additions
Alternatively, Boot2Docker includes the VirtualBox Guest Additions built in for the express purpose of using VirtualBox folder sharing.
The first of the following share names that exists (if any) will be automatically mounted at the location specified:
If some other path or share is desired, it can be mounted at run time by doing something like:
$ mount -t vboxsf -o uid=1000,gid=50 your-other-share-name /some/mount/location
It is also important to note that in the future, the plan is to have any share
which is created in VirtualBox with the "automount" flag turned on be mounted
during boot at the directory of the share name (ie, a share named
would be automounted at
In case it isn't already clear, the Linux host support here is currently hazy.
You can share your
/home/jsmith directory as
Users or one of the
other supported automount locations listed above, but note that you will then
need to manually convert your
docker run -v /home/...:... bind-mount host
paths accordingly (ie,
docker run -v /Users/...:...). As noted in the
previous paragraph however, this is likely to change in the future as soon as a
more suitable/scalable solution is found and implemented.
Installing secure Registry certificates
You can add your Registry server's public certificate (in
.pem format) into
/var/lib/boot2docker/certs/ directory, and Boot2Docker will automatically
load it from the persistence partition at boot.
You may need to add several certificates (as separate
.pem files) to this
directory, depending on the CA signing chain used for your certificate.
As of Docker version 1.3.1, if your registry doesn't support HTTPS, you must add it as an insecure registry.
$ boot2docker init $ boot2docker up $ boot2docker ssh "echo $'EXTRA_ARGS=\"--insecure-registry <YOUR INSECURE HOST>\"' | sudo tee -a /var/lib/boot2docker/profile && sudo /etc/init.d/docker restart"
then you should be able to do a docker push/pull.
Running behind a VPN (Cisco AnyConnect, etc)
So sometimes if you are behind a VPN, you'll get an
i/o timeout error.
The current work around is to forward the port in the boot2docker-vm.
If you get an error like the following:
Sending build context to Docker daemon 2014/11/19 13:53:33 Post https://192.168.59.103:2376/v1.15/build?rm=1&t=your-tag: dial tcp 192.168.59.103:2376: i/o timeout
That means you have to forward port
2376, which can be done like so:
- Open VirtualBox
- Open Settings > Network for your 'boot2docker-vm'
- Select the adapter that is 'Attached To': 'NAT' and click 'Port Forwarding'.
- Add a new rule:
- Protocol: TCP
- Host IP: 127.0.0.1
- Host Port: 5555
- Guest Port: 2376
boot2docker management tool allows you to customise many options from both
the command line, or by setting them in its configuration file.
boot2docker config for more (including the format of the configuration
SSH into VM
$ boot2docker ssh
boot2docker auto logs in using the generated SSH key, but if you want to SSH
into the machine manually (or you're not using a
boot2docker managed VM), the
user: docker pass: tcuser
Boot2docker uses Tiny Core Linux, which runs from RAM and so does not persist filesystem changes by default.
When you run
boot2docker init, the
boot2docker tool auto-creates a disk that
will be automounted and used to persist your docker data in
/var/lib/boot2docker. This virtual disk will be removed when you run
boot2docker delete. It will also persist the SSH keys of the machine.
Changes outside of these directories will be lost after powering down or
restarting the VM - to make permanent modifications see the
If you are not using the
boot2docker management tool, you can create an
btrfs formatted partition with the label
boot2docker-data /dev/sdX5) to your VM or host, and Boot2Docker will automount
/mnt/sdX and then softlink
Install on any device
To 'install' the ISO onto an SD card, USB-Stick or even empty hard disk, you can
dd if=boot2docker.iso of=/dev/sdX. This will create the small boot
partition, and install an MBR.
Build your own Boot2Docker ISO
Goto How to build for Documentation on how to build your own Boot2Docker ISOs.
See the workarounds doc for solutions to known issues.
boot2docker up doesn't work (OSX)
Sometimes OSX will install updates that break VirtualBox and require a restart of the kernel extensions that boot2docker needs in order to run. If you go to boot boot2docker after some updates or a system restart and you get an output such as the following:
$ boot2docker up error in run: Failed to start machine "boot2docker-vm" (run again with -v for details)
You may need to reload the kernel extensions in order to get your system functioning again.
In this case, try running the following script (supplied with Virtual Box):
$ sudo /Library/Application\ Support/VirtualBox/LaunchDaemons/VirtualBoxStartup.sh restart
You should see output such as:
/Applications/VirtualBox.app/Contents/MacOS/VBoxAutostart => /Applications/VirtualBox.app/Contents/MacOS/VBoxAutostart-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxBalloonCtrl => /Applications/VirtualBox.app/Contents/MacOS/VBoxBalloonCtrl-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxDD2GC.gc => /Applications/VirtualBox.app/Contents/MacOS/VBoxDD2GC.gc-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxDDGC.gc => /Applications/VirtualBox.app/Contents/MacOS/VBoxDDGC.gc-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxExtPackHelperApp => /Applications/VirtualBox.app/Contents/MacOS/VBoxExtPackHelperApp-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxHeadless => /Applications/VirtualBox.app/Contents/MacOS/VBoxHeadless-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxManage => /Applications/VirtualBox.app/Contents/MacOS/VBoxManage-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxNetAdpCtl => /Applications/VirtualBox.app/Contents/MacOS/VBoxNetAdpCtl-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxNetDHCP => /Applications/VirtualBox.app/Contents/MacOS/VBoxNetDHCP-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxNetNAT => /Applications/VirtualBox.app/Contents/MacOS/VBoxNetNAT-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxSVC => /Applications/VirtualBox.app/Contents/MacOS/VBoxSVC-amd64 /Applications/VirtualBox.app/Contents/MacOS/VBoxXPCOMIPCD => /Applications/VirtualBox.app/Contents/MacOS/VBoxXPCOMIPCD-amd64 /Applications/VirtualBox.app/Contents/MacOS/VMMGC.gc => /Applications/VirtualBox.app/Contents/MacOS/VMMGC.gc-amd64 /Applications/VirtualBox.app/Contents/MacOS/VirtualBox => /Applications/VirtualBox.app/Contents/MacOS/VirtualBox-amd64 /Applications/VirtualBox.app/Contents/MacOS/VirtualBoxVM => /Applications/VirtualBox.app/Contents/MacOS/VirtualBoxVM-amd64 /Applications/VirtualBox.app/Contents/MacOS/vboxwebsrv => /Applications/VirtualBox.app/Contents/MacOS/vboxwebsrv-amd64 Loading VBoxDrv.kext Loading VBoxUSB.kext Loading VBoxNetFlt.kext Loading VBoxNetAdp.kext
Now the VM should boot properly.