8.3 KiB
runc
runc is a CLI tool for spawning and running containers according to the OCF specification.
State of the project
Currently runc is an implementation of the OCF specification. We are currently sprinting
to have a v1 of the spec out within a quick timeframe of a few weeks, ~July 2015,
so the runc config format will be constantly changing until
the spec is finalized. However, we encourage you to try out the tool and give feedback.
OCF
How does runc integrate with the Open Container Format? runc depends on the types
specified in the specs repository. Whenever
the specification is updated and ready to be versioned runc will update it's dependency
on the specs repository and support the update spec.
Building:
At the time of writing, runc only builds on the Linux platform.
# 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
Using:
To run a container, execute runc start in the bundle's root directory:
runc start
/ $ ps
PID USER COMMAND
1 daemon sh
5 daemon sh
/ $
Or you can specify the path to a JSON configuration file:
runc start config.json
/ $ ps
PID USER COMMAND
1 daemon sh
5 daemon sh
/ $
Note: the use of the start command is required when specifying a
configuration file.
OCF Container JSON Format:
Below is a sample config.json configuration file. It assumes that
the file-system is found in a directory called rootfs and there is a
user with uid and gid of 0 defined within that file-system.
{
"version": "pre-draft",
"platform": {
"os": "linux",
"arch": "amd64"
},
"process": {
"terminal": true,
"user": {
"uid": 0,
"gid": 0,
"additionalGids": null
},
"args": [
"sh"
],
"env": [
"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin",
"TERM=xterm"
],
"cwd": ""
},
"root": {
"path": "rootfs",
"readonly": true
},
"hostname": "shell",
"mounts": [
{
"type": "proc",
"source": "proc",
"destination": "/proc",
"options": ""
},
{
"type": "tmpfs",
"source": "tmpfs",
"destination": "/dev",
"options": "nosuid,strictatime,mode=755,size=65536k"
},
{
"type": "devpts",
"source": "devpts",
"destination": "/dev/pts",
"options": "nosuid,noexec,newinstance,ptmxmode=0666,mode=0620,gid=5"
},
{
"type": "tmpfs",
"source": "shm",
"destination": "/dev/shm",
"options": "nosuid,noexec,nodev,mode=1777,size=65536k"
},
{
"type": "mqueue",
"source": "mqueue",
"destination": "/dev/mqueue",
"options": "nosuid,noexec,nodev"
},
{
"type": "sysfs",
"source": "sysfs",
"destination": "/sys",
"options": "nosuid,noexec,nodev"
},
{
"type": "cgroup",
"source": "cgroup",
"destination": "/sys/fs/cgroup",
"options": "nosuid,noexec,nodev,relatime,ro"
}
],
"linux": {
"uidMapping": null,
"gidMapping": null,
"rlimits": [
{
"type": 7,
"hard": 1024,
"soft": 1024
}
],
"systemProperties": null,
"resources": {
"disableOOMKiller": false,
"memory": {
"limit": 0,
"reservation": 0,
"swap": 0,
"kernel": 0,
"swappiness": -1
},
"cpu": {
"shares": 0,
"quota": 0,
"period": 0,
"realtimeRuntime": 0,
"realtimePeriod": 0,
"cpus": "",
"mems": ""
},
"blockIO": {
"blkioWeight": 0,
"blkioWeightDevice": "",
"blkioThrottleReadBpsDevice": "",
"blkioThrottleWriteBpsDevice": "",
"blkioThrottleReadIopsDevice": "",
"blkioThrottleWriteIopsDevice": ""
},
"hugepageLimits": null,
"network": {
"classId": "",
"priorities": null
}
},
"namespaces": [
{
"type": "pid",
"path": ""
},
{
"type": "network",
"path": ""
},
{
"type": "ipc",
"path": ""
},
{
"type": "uts",
"path": ""
},
{
"type": "mount",
"path": ""
}
],
"capabilities": [
"AUDIT_WRITE",
"KILL",
"NET_BIND_SERVICE"
],
"devices": [
{
"type": 99,
"path": "/dev/null",
"major": 1,
"minor": 3,
"permissions": "rwm",
"fileMode": 438,
"uid": 0,
"gid": 0
},
{
"type": 99,
"path": "/dev/random",
"major": 1,
"minor": 8,
"permissions": "rwm",
"fileMode": 438,
"uid": 0,
"gid": 0
},
{
"type": 99,
"path": "/dev/full",
"major": 1,
"minor": 7,
"permissions": "rwm",
"fileMode": 438,
"uid": 0,
"gid": 0
},
{
"type": 99,
"path": "/dev/tty",
"major": 5,
"minor": 0,
"permissions": "rwm",
"fileMode": 438,
"uid": 0,
"gid": 0
},
{
"type": 99,
"path": "/dev/zero",
"major": 1,
"minor": 5,
"permissions": "rwm",
"fileMode": 438,
"uid": 0,
"gid": 0
},
{
"type": 99,
"path": "/dev/urandom",
"major": 1,
"minor": 9,
"permissions": "rwm",
"fileMode": 438,
"uid": 0,
"gid": 0
}
],
}
}
Examples:
Using a Docker image (requires version 1.3 or later)
To test using Docker's busybox image follow these steps:
- Install
dockerand download thebusyboximage:docker pull busybox - Create a container from that image and export its contents to a tar file:
docker export $(docker create busybox) > busybox.tar - Untar the contents to create your filesystem directory:
mkdir rootfs
tar -C rootfs -xf busybox.tar
- Create a file called
config.jsonusing the example from above. You can also generate a spec usingrunc spec, redirecting the output intoconfig.json - Execute
runc startand you should be placed into a shell where you can runps:
$ runc start
/ # ps
PID USER COMMAND
1 root sh
9 root ps
Using runc with systemd
[Unit]
Description=Minecraft Build Server
Documentation=http://minecraft.net
After=network.target
[Service]
CPUQuota=200%
MemoryLimit=1536M
ExecStart=/usr/local/bin/runc
Restart=on-failure
WorkingDirectory=/containers/minecraftbuild
[Install]
WantedBy=multi-user.target