CLI tool for spawning and running containers according to the OCI specification
Clone or download
mrunalp Merge pull request #1862 from AkihiroSuda/decompose-rootless-pr
Disable rootless mode except RootlessCgMgr when executed as the root in userns (fix Docker-in-LXD regression)
Latest commit a00bf01 Oct 15, 2018
Permalink
Failed to load latest commit information.
contrib doc: fix typo Sep 7, 2018
docs docs: add information about terminals Jun 24, 2018
libcontainer Merge pull request #1862 from AkihiroSuda/decompose-rootless-pr Oct 16, 2018
man Add missing data to man page Aug 16, 2018
script make: validate C format Jan 24, 2018
tests doc: fix typo Sep 7, 2018
vendor Update console dependency to fix runc exec on BE Feb 21, 2018
.gitignore travis: test cross compilation Jun 16, 2018
.pullapprove.yml Disallow self-LGTMs Jun 1, 2016
.travis.yml fix build break Oct 12, 2018
CONTRIBUTING.md *: add information about security mailing list Dec 3, 2016
Dockerfile Dockerfile: update criu to v3.10 + checkpoint-restore/criu@27034e7 Aug 12, 2018
LICENSE Initial commit of runc binary Jun 22, 2015
MAINTAINERS Remove @avagin as a maintainer Aug 2, 2017
MAINTAINERS_GUIDE.md trailing punctuation in header Dec 2, 2016
Makefile Add docker proxy settings for make test in a proxy environment Aug 22, 2018
NOTICE Move libcontainer documenation to root of repo Jun 26, 2015
PRINCIPLES.md Move libcontainer documenation to root of repo Jun 26, 2015
README.md Add docker proxy settings for make test in a proxy environment Aug 22, 2018
VERSION VERSION: back to development Feb 27, 2018
checkpoint.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
create.go Prepare startContainer() to have more action May 1, 2017
delete.go Moving the rest of runc to x/sys/unix May 22, 2017
events.go libcontainer: add support for Intel RDT/CAT in runc Sep 1, 2017
exec.go Fix race in runc exec Jun 1, 2018
init.go runc only works on Linux so remove putative Solaris and unsupported main Jun 29, 2017
kill.go kill.go: Remove unnecessary checks Jan 26, 2018
list.go list: stop casting unknown UIDs to their unicode values Jul 11, 2017
main.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
notify_socket.go libcontainer/specconv/spec_linux: Support empty 'type' for bind mounts Mar 7, 2018
pause.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
ps.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
restore.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
rlimit_linux.go error strings should not be capitalized or end with punctuation Dec 1, 2016
rootless_linux.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
run.go Prepare startContainer() to have more action May 1, 2017
signalmap.go Stop using unix.SIGUNUSED which has been removed from golang.org/x/sys Jun 17, 2018
signalmap_mipsx.go Add support for mips/mips64 Jun 2, 2017
signals.go doc: fix typo Sep 7, 2018
spec.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
start.go Only allow single container operation Mar 8, 2017
state.go Check args numbers before application start Nov 29, 2016
tty.go Merge pull request #1895 from giuseppe/fix-tty-hang Sep 20, 2018
update.go intelrdt: add update command support Sep 19, 2017
utils.go main: support rootless mode in userns May 10, 2018
utils_linux.go Disable rootless mode except RootlessCgMgr when executed as the root … Sep 7, 2018
vendor.conf Update console dependency to fix runc exec on BE Feb 21, 2018

README.md

runc

Build Status Go Report Card GoDoc

Introduction

runc is a CLI tool for spawning and running containers according to the OCI specification.

Releases

runc depends on and tracks the runtime-spec repository. We will try to make sure that runc and the OCI specification major versions stay in lockstep. This means that runc 1.0.0 should implement the 1.0 version of the specification.

You can find official releases of runc on the release page.

Security

If you wish to report a security issue, please disclose the issue responsibly to security@opencontainers.org.

Building

runc currently supports the Linux platform with various architecture support. It must be built with Go version 1.6 or higher in order for some features to function properly.

In order to enable seccomp support you will need to install libseccomp on your platform.

e.g. libseccomp-devel for CentOS, or libseccomp-dev for Ubuntu

Otherwise, if you do not want to build runc with seccomp support you can add BUILDTAGS="" when running make.

# create a 'github.com/opencontainers' in your GOPATH/src
cd github.com/opencontainers
git clone https://github.com/opencontainers/runc
cd runc

make
sudo make install

You can also use go get to install to your GOPATH, assuming that you have a github.com parent folder already created under src:

go get github.com/opencontainers/runc
cd $GOPATH/src/github.com/opencontainers/runc
make
sudo make install

runc will be installed to /usr/local/sbin/runc on your system.

Build Tags

runc supports optional build tags for compiling support of various features. To add build tags to the make option the BUILDTAGS variable must be set.

make BUILDTAGS='seccomp apparmor'
Build Tag Feature Dependency
seccomp Syscall filtering libseccomp
selinux selinux process and mount labeling
apparmor apparmor profile support
ambient ambient capability support kernel 4.3

Running the test suite

runc currently supports running its test suite via Docker. To run the suite just type make test.

make test

There are additional make targets for running the tests outside of a container but this is not recommended as the tests are written with the expectation that they can write and remove anywhere.

You can run a specific test case by setting the TESTFLAGS variable.

# make test TESTFLAGS="-run=SomeTestFunction"

You can run a specific integration test by setting the TESTPATH variable.

# make test TESTPATH="/checkpoint.bats"

You can run a test in your proxy environment by setting DOCKER_BUILD_PROXY and DOCKER_RUN_PROXY variables.

# make test DOCKER_BUILD_PROXY="--build-arg HTTP_PROXY=http://yourproxy/" DOCKER_RUN_PROXY="-e HTTP_PROXY=http://yourproxy/"

Dependencies Management

runc uses vndr for dependencies management. Please refer to vndr for how to add or update new dependencies.

Using runc

Creating an OCI Bundle

In order to use runc you must have your container in the format of an OCI bundle. If you have Docker installed you can use its export method to acquire a root filesystem from an existing Docker container.

# create the top most bundle directory
mkdir /mycontainer
cd /mycontainer

# create the rootfs directory
mkdir rootfs

# export busybox via Docker into the rootfs directory
docker export $(docker create busybox) | tar -C rootfs -xvf -

After a root filesystem is populated you just generate a spec in the format of a config.json file inside your bundle. runc provides a spec command to generate a base template spec that you are then able to edit. To find features and documentation for fields in the spec please refer to the specs repository.

runc spec

Running Containers

Assuming you have an OCI bundle from the previous step you can execute the container in two different ways.

The first way is to use the convenience command run that will handle creating, starting, and deleting the container after it exits.

# run as root
cd /mycontainer
runc run mycontainerid

If you used the unmodified runc spec template this should give you a sh session inside the container.

The second way to start a container is using the specs lifecycle operations. This gives you more power over how the container is created and managed while it is running. This will also launch the container in the background so you will have to edit the config.json to remove the terminal setting for the simple examples here. Your process field in the config.json should look like this below with "terminal": false and "args": ["sleep", "5"].

        "process": {
                "terminal": false,
                "user": {
                        "uid": 0,
                        "gid": 0
                },
                "args": [
                        "sleep", "5"
                ],
                "env": [
                        "PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
                        "TERM=xterm"
                ],
                "cwd": "/",
                "capabilities": {
                        "bounding": [
                                "CAP_AUDIT_WRITE",
                                "CAP_KILL",
                                "CAP_NET_BIND_SERVICE"
                        ],
                        "effective": [
                                "CAP_AUDIT_WRITE",
                                "CAP_KILL",
                                "CAP_NET_BIND_SERVICE"
                        ],
                        "inheritable": [
                                "CAP_AUDIT_WRITE",
                                "CAP_KILL",
                                "CAP_NET_BIND_SERVICE"
                        ],
                        "permitted": [
                                "CAP_AUDIT_WRITE",
                                "CAP_KILL",
                                "CAP_NET_BIND_SERVICE"
                        ],
                        "ambient": [
                                "CAP_AUDIT_WRITE",
                                "CAP_KILL",
                                "CAP_NET_BIND_SERVICE"
                        ]
                },
                "rlimits": [
                        {
                                "type": "RLIMIT_NOFILE",
                                "hard": 1024,
                                "soft": 1024
                        }
                ],
                "noNewPrivileges": true
        },

Now we can go through the lifecycle operations in your shell.

# run as root
cd /mycontainer
runc create mycontainerid

# view the container is created and in the "created" state
runc list

# start the process inside the container
runc start mycontainerid

# after 5 seconds view that the container has exited and is now in the stopped state
runc list

# now delete the container
runc delete mycontainerid

This allows higher level systems to augment the containers creation logic with setup of various settings after the container is created and/or before it is deleted. For example, the container's network stack is commonly set up after create but before start.

Rootless containers

runc has the ability to run containers without root privileges. This is called rootless. You need to pass some parameters to runc in order to run rootless containers. See below and compare with the previous version. Run the following commands as an ordinary user:

# Same as the first example
mkdir ~/mycontainer
cd ~/mycontainer
mkdir rootfs
docker export $(docker create busybox) | tar -C rootfs -xvf -

# The --rootless parameter instructs runc spec to generate a configuration for a rootless container, which will allow you to run the container as a non-root user.
runc spec --rootless

# The --root parameter tells runc where to store the container state. It must be writable by the user.
runc --root /tmp/runc run mycontainerid

Supervisors

runc can be used with process supervisors and init systems to ensure that containers are restarted when they exit. An example systemd unit file looks something like this.

[Unit]
Description=Start My Container

[Service]
Type=forking
ExecStart=/usr/local/sbin/runc run -d --pid-file /run/mycontainerid.pid mycontainerid
ExecStopPost=/usr/local/sbin/runc delete mycontainerid
WorkingDirectory=/mycontainer
PIDFile=/run/mycontainerid.pid

[Install]
WantedBy=multi-user.target