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CRICTL User Guide

This document presumes you already have containerd and cri-containerd installed and running.

This document is for developers who wish to debug, inspect, and manage their pods, containers, and container images.

Before generating issues against this document, containerd, cri-containerd, or crictl please make sure the issue has not already been submitted.

Install crictl

If you have not already installed crictl please install the version compatible with the cri-containerd you are using. If you are a user, your deployment should have installed crictl for you. If not, get it from your release tarball. If you are a developer the current version of crictl is specified here. A helper command has been included to install the dependencies at the right version:

$ make install.deps
  • Note: The file named /etc/crictl.yaml is used to configure crictl so you don't have to repeatedly specify the runtime sock used to connect crictl to the container runtime:
$ cat /etc/crictl.yaml
runtime-endpoint: /var/run/cri-containerd.sock
image-endpoint: /var/run/cri-containerd.sock
timeout: 10
debug: true

Download and Inspect a Container Image

The pull command tells the container runtime to download a container image from a container registry.

$ crictl pull busybox
  ...
$ crictl inspecti busybox
  ... displays information about the image.

Directly Load a Container Image

Another way to load an image into the container runtime is with the load command. With the load command you inject a container image into the container runtime from a file. First you need to create a container image tarball. For example to create an image tarball for a pause container using Docker:

$ docker pull k8s.gcr.io/pause-amd64:3.1
  3.1: Pulling from pause-amd64
  67ddbfb20a22: Pull complete
  Digest: sha256:59eec8837a4d942cc19a52b8c09ea75121acc38114a2c68b98983ce9356b8610
  Status: Downloaded newer image for k8s.gcr.io/pause-amd64:3.1
$ docker save k8s.gcr.io/pause-amd64:3.1 -o pause.tar

Then load the container image into the container runtime:

$ sudo ctr cri load pause.tar
  Loaded image: k8s.gcr.io/pause-amd64:3.1

List images and inspect the pause image:

$ sudo crictl images
IMAGE                       TAG                 IMAGE ID            SIZE
docker.io/library/busybox   latest              f6e427c148a76       728kB
k8s.gcr.io/pause-amd64      3.1                 da86e6ba6ca19       746kB
$ sudo crictl inspecti da86e6ba6ca19
  ... displays information about the pause image.
$ sudo crictl inspecti k8s.gcr.io/pause-amd64:3.1
  ... displays information about the pause image.

Run a pod sandbox (using a config file)

$ cat sandbox-config.json
{
    "metadata": {
        "name": "nginx-sandbox",
        "namespace": "default",
        "attempt": 1,
        "uid": "hdishd83djaidwnduwk28bcsb"
    },
    "linux": {
    }
}

$ crictl runp sandbox-config.json
e1c83b0b8d481d4af8ba98d5f7812577fc175a37b10dc824335951f52addbb4e
$ crictl pods
PODSANDBOX ID       CREATED             STATE               NAME               NAMESPACE          ATTEMPT
e1c83b0b8d481       2 hours ago         SANDBOX_READY       nginx-sandbox      default            1
$ crictl inspectp e1c8
  ... displays information about the pod and the pod sandbox pause container.
  • Note: As shown above, you may use truncated IDs if they are unique.
  • Other commands to manage the pod include stops ID to stop a running pod and rmp ID to remove a pod sandbox.

Create and Run a Container in a Pod Sandbox (using a config file)

$ cat sandbox-config.json
{
    "metadata": {
        "name": "nginx-sandbox",
        "namespace": "default",
        "attempt": 1,
        "uid": "hdishd83djaidwnduwk28bcsb"
    },
    "linux": {
    }
}

$ cat container-config.json
{
  "metadata": {
      "name": "busybox"
  },
  "image":{
      "image": "busybox"
  },
  "command": [
      "top"
  ],
  "linux": {
  }
}

$ crictl create e1c83 container-config.json sandbox-config.json
0a2c761303163f2acaaeaee07d2ba143ee4cea7e3bde3d32190e2a36525c8a05
$ crictl ps
CONTAINER ID        IMAGE               CREATED             STATE               NAME                ATTEMPT
0a2c761303163       docker.io/busybox   2 hours ago         CONTAINER_CREATED   busybox             0
$ crictl start 0a2c
0a2c761303163f2acaaeaee07d2ba143ee4cea7e3bde3d32190e2a36525c8a05
$ crictl ps
CONTAINER ID        IMAGE               CREATED             STATE               NAME                ATTEMPT
0a2c761303163       docker.io/busybox   2 hours ago         CONTAINER_RUNNING   busybox             0
$ crictl inspect 0a2c7
  ... show detailed information about the container

Exec a Command in the Container

$ crictl exec -i -t 0a2c ls
bin   dev   etc   home  proc  root  sys   tmp   usr   var

Display Stats for the Container

$ crictl stats
CONTAINER           CPU %               MEM                 DISK                INODES
0a2c761303163f      0.00                991.2kB             16.38kB             6
  • Other commands to manage the container include stop ID to stop a running container and rm ID to remove a container.

Display Version Information

$ crictl version
Version:  0.1.0
RuntimeName:  cri-containerd
RuntimeVersion:  1.0.0-alpha.1-167-g737efe7-dirty
RuntimeApiVersion:  0.0.0

Display Status & Configuration Information about Containerd & CRI-Containerd

$ crictl info
{
  "status": {
    "conditions": [
      {
        "type": "RuntimeReady",
        "status": true,
        "reason": "",
        "message": ""
      },
      {
        "type": "NetworkReady",
        "status": true,
        "reason": "",
        "message": ""
      }
    ]
  },
  "config": {
    "containerd": {
      "rootDir": "/var/lib/containerd",
      "snapshotter": "overlayfs",
      "endpoint": "/run/containerd/containerd.sock",
      "runtime": "io.containerd.runtime.v1.linux"
    },
    "cni": {
      "binDir": "/opt/cni/bin",
      "confDir": "/etc/cni/net.d"
    },
    "socketPath": "/var/run/cri-containerd.sock",
    "rootDir": "/var/lib/cri-containerd",
    "streamServerPort": "10010",
    "sandboxImage": "gcr.io/google_containers/pause:3.0",
    "statsCollectPeriod": 10,
    "oomScore": -999,
    "enableProfiling": true,
    "profilingPort": "10011",
    "profilingAddress": "127.0.0.1"
  }
}

More Information

See here for information about crictl.