145 lines
4.2 KiB
Markdown
145 lines
4.2 KiB
Markdown
[](https://jenkins.dockerproject.org/job/runc Master)
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## runc
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`runc` is a CLI tool for spawning and running containers according to the OCF specification.
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## State of the project
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Currently `runc` is an implementation of the OCI specification. We are currently sprinting
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to have a v1 of the spec out. So the `runc` config format will be constantly changing until
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the spec is finalized. However, we encourage you to try out the tool and give feedback.
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### OCF
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How does `runc` integrate with the Open Container Initiative Specification?
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`runc` depends on the types specified in the
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[specs](https://github.com/opencontainers/specs) repository. Whenever the
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specification is updated and ready to be versioned `runc` will update its dependency
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on the specs repository and support the update spec.
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### Building:
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At the time of writing, runc only builds on the Linux platform.
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```bash
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# create a 'github.com/opencontainers' in your GOPATH/src
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cd github.com/opencontainers
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git clone https://github.com/opencontainers/runc
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cd runc
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make
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sudo make install
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```
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In order to enable seccomp support you will need to install libseccomp on your platform.
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If you do not want to build `runc` with seccomp support you can add `BUILDTAGS=""` when running make.
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#### Build Tags
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`runc` supports optional build tags for compiling in support for various features.
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| Build Tag | Feature | Dependency |
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|-----------|------------------------------------|-------------|
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| seccomp | Syscall filtering | libseccomp |
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| selinux | selinux process and mount labeling | <none> |
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| apparmor | apparmor profile support | libapparmor |
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### Testing:
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You can run tests for runC by using command:
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```bash
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# make test
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```
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Note that test cases are run in Docker container, so you need to install
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`docker` first. And test requires mounting cgroups inside container, it's
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done by docker now, so you need a docker version newer than 1.8.0-rc2.
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You can also run specific test cases by:
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```bash
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# make test TESTFLAGS="-run=SomeTestFunction"
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```
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### Using:
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To run a container with the id "test", execute `runc start` with the containers id as arg one
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in the bundle's root directory:
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```bash
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runc start test
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/ $ ps
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PID USER COMMAND
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1 daemon sh
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5 daemon sh
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/ $
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```
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### OCI Container JSON Format:
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OCI container JSON format is based on OCI [specs](https://github.com/opencontainers/specs).
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You can generate JSON files by using `runc spec`.
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It assumes that the file-system is found in a directory called
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`rootfs` and there is a user with uid and gid of `0` defined within that file-system.
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### Examples:
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#### Using a Docker image (requires version 1.3 or later)
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To test using Docker's `busybox` image follow these steps:
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* Install `docker` and download the `busybox` image: `docker pull busybox`
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* Create a container from that image and export its contents to a tar file:
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`docker export $(docker create busybox) > busybox.tar`
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* Untar the contents to create your filesystem directory:
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```
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mkdir rootfs
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tar -C rootfs -xf busybox.tar
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```
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* Create `config.json` by using `runc spec`.
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* Execute `runc start` and you should be placed into a shell where you can run `ps`:
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```
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$ runc start test
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/ # ps
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PID USER COMMAND
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1 root sh
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9 root ps
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```
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#### Using runc with systemd
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To use runc with systemd, you can create a unit file
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`/usr/lib/systemd/system/minecraft.service` as below (edit your
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own Description or WorkingDirectory or service name as you need).
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```service
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[Unit]
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Description=Minecraft Build Server
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Documentation=http://minecraft.net
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After=network.target
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[Service]
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CPUQuota=200%
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MemoryLimit=1536M
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ExecStart=/usr/local/bin/runc start minecraft
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Restart=on-failure
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WorkingDirectory=/containers/minecraftbuild
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[Install]
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WantedBy=multi-user.target
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```
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Make sure you have the bundle's root directory and JSON configs in
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your WorkingDirectory, then use systemd commands to start the service:
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```bash
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systemctl daemon-reload
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systemctl start minecraft.service
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```
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Note that if you use JSON configs by `runc spec`, you need to modify
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`config.json` and change `process.terminal` to false so runc won't
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create tty, because we can't set terminal from the stdin when using
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systemd service.
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