Project: rkt (Runtime / Container Runtime)
File: prepare.md

rkt can prepare images to run in a pod. This means it will fetch (if necessary) the images, extract them in its internal tree store, and allocate a pod UUID. If overlay fs is not supported or disabled, it will also copy the tree in the pod rootfs. Support for overlay fs will be auto-detected if `--no-overlay` is set to `false`. If an unsupported filesystem is detected, rkt will print a warning message and continue preparing the pod by falling back in non-overlay mode as described above: ``` image: using image from local store for image name coreos.com/rkt/stage1-coreos:1.30.0 image: remote fetching from URL "docker://busybox" Downloading sha256:8ddc19f1652 [===============================] 668 KB / 668 KB prepare: disabling overlay support: "unsupported filesystem: missing d_type support" ``` The following conditions can lead to non-overlay mode: The data directory (usually `/var/lib/rkt`) is on ... an AUFS filesystem a ZFS filesystem a XFS filesystem having `ftype=0` a file system where the `dtype` field is set to `DTUNKNOWN`, see getdents(2) In this way, the pod is ready to be launched immediately by the command. Running `rkt prepare` + `rkt run-prepared` is semantically equivalent to running . Therefore, the supported arguments are mostly the same as in `run` except runtime arguments like `--interactive` or `--mds-register`. ``` rkt prepare coreos.com/etcd:v2.0.10 rkt: using image from local store for image name coreos.com/rkt/stage1-coreos:1.30.0 rkt: searching for app image coreos.com/etcd:v2.0.10 rkt: remote fetching from url https://github.com/coreos/etcd/releases/download/v2.0.10/etcd-v2.0.10-linux-amd64.aci prefix: "coreos.com/etcd" key: "https://coreos.com/dist/pubkeys/aci-pubkeys.gpg" gpg key fingerprint is: 8B86 DE38 890D DB72 9186 7B02 5210 BD88 8818 2190 CoreOS ACI Builder <release@coreos.com> Key "https://coreos.com/dist/pubkeys/aci-pubkeys.gpg" already in the keystore Downloading signature from https://github.com/coreos/etcd/releases/download/v2.0.10/etcd-v2.0.10-linux-amd64.aci.asc Downloading signature: [=======================================] 819 B/819 B Downloading ACI: [=============================================] 3.79 MB/3.79 MB rkt: signature verified: CoreOS ACI Builder <release@coreos.com> c9fad0e6-8236-4fc2-ad17-55d0a4c7d742 ``` | Flag | Default | Options | Description | | | | | | | `--user-annotation` | none | annotation add to the app's UserAnnotations field | Set the app's annotations (example: '--annotation=foo=bar'). | | `--caps-remove` | none | capability to remove (example: '--caps-remove=CAP\SYS\CHROOT,CAP\_MKNOD') | Capabilities to remove from the process's capabilities bounding set, all others from the default set will be included | | `--caps-retain` | none | capability to retain (example: '--caps-remove=CAP\SYS\ADMIN,CAP\NET\ADMIN') | Capabilities to retain in the process's capabilities bounding set, all others will be removed | | `--environment` | none | environment variables add to the app's environment variables | Set the app's environment variables (example: '--environment=foo=bar'). | | `--exec` | none | Path to executable | Override the exec command for the preceding image. | | `--group` | root | gid, groupname or file path | Group override for the preceding image (example: '--group=group') | | `--inherit-env` | `false` | `true` or `false` | Inherit all environment variables not set by

| | `--user-label` | none | label add to the apps' UserLabels field | Set the app's labels (example: '--label=foo=bar'). | | `--mount` | none | Mount syntax (ex. `--mount volume=NAME,target=PATH`) | Mount point binding a volume to a path within an app. See . | | `--name` | none | Name of the app | Set the name of the app (example: '--name=foo'). If not set, then the app name default to the image's name | | `--no-overlay` | `false` | `true` or `false` | Disable the overlay filesystem. | | `--pull-policy` | `new` | `never`, `new`, or `update` | Sets the policy for when to fetch an image. See | | `--pod-manifest` | none | A path | The path to the pod manifest. If it's non-empty, then only `--net`, `--no-overlay` and `--interactive` will have effect. | | `--port` | none | A port name and number pair | Container port name to expose through host port number. Requires . Syntax: `--port=NAME:HOSTPORT` The NAME is that given in the ACI. By convention, Docker containers' EXPOSEd ports are given a name formed from the port number, a hyphen, and the protocol, e.g., `80-tcp`, giving something like `--port=80-tcp:8080` | | `--private-users` | `false` | `true` or `false` | Run within user namespaces | | `--quiet` | `false` | `true` or `false` | Suppress superfluous output on stdout, print only the UUID on success | | `--set-env` | `` | An environment variable. Syntax `NAME=VALUE` | An environment variable to set for apps | | `--set-env-file` | `` | Path of an environment variables file | Environment variables to set for apps | | `--signature` | `` | A file path | Local signature file to use in validating the preceding image | | `--stage1-url` | `` | A URL to a stage1 image. HTTP/HTTPS/File/Docker URLs are supported | Image to use as stage1 | | `--stage1-path` | `` | A path to a stage1 image. Absolute and relative paths are supported | Image to use as stage1 | | `--stage1-name` | `` | A name of a stage1 image. Will perform a discovery if the image is not in the store | Image to use as stage1 | | `--stage1-hash` | `` | A hash of a stage1 image. The image must exist in the store | Image to use as stage1 | | `--stage1-from-dir` | `` | A stage1 image file inside the default stage1 images directory | Image to use as stage1 | | `--user` | none | uid, username or file path | user override for the preceding image (example: '--user=user') | | `--volume` | `` | Volume syntax (`NAME,kind=KIND,source=PATH,readOnly=BOOL,recursive=BOOL`). See | Volumes to make available in the pod | See the table with .