Debugging Kubernetes nodes with crictl [page]deterministic

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`crictl` is a command-line interface for CRI-compatible container runtimes. You can use it to inspect and debug container runtimes and applications on a Kubernetes node. `crictl` and its source are hosted in the [cri-tools](https://github.com/kubernetes-sigs/cri-tools) repository.

`crictl` requires a Linux operating system with a CRI runtime.

## Installing crictl

You can download a compressed archive `crictl` from the cri-tools [release page](https://github.com/kubernetes-sigs/cri-tools/releases), for several different architectures. Download the version that corresponds to your version of Kubernetes. Extract it and move it to a location on your system path, such as `/usr/local/bin/`.

## General usage

The `crictl` command has several subcommands and runtime flags. Use `crictl help` or `crictl <subcommand> help` for more details.

You can set the endpoint for `crictl` by doing one of the following:

* Set the `--runtime-endpoint` and `--image-endpoint` flags. * Set the `CONTAINER_RUNTIME_ENDPOINT` and `IMAGE_SERVICE_ENDPOINT` environment variables. * Set the endpoint in the configuration file `/etc/crictl.yaml`. To specify a different file, use the `--config=PATH_TO_FILE` flag when you run `crictl`.

If you don't set an endpoint, `crictl` attempts to connect to a list of known endpoints, which might result in an impact to performance.

You can also specify timeout values when connecting to the server and enable or disable debugging, by specifying `timeout` or `debug` values in the configuration file or using the `--timeout` and `--debug` command-line flags.

To view or edit the current configuration, view or edit the contents of `/etc/crictl.yaml`. For example, the configuration when using the `containerd` container runtime would be similar to this:

``` runtime-endpoint: unix:///var/run/containerd/containerd.sock image-endpoint: unix:///var/run/containerd/containerd.sock timeout: 10 debug: true ```

To learn more about `crictl`, refer to the [`crictl` documentation](https://github.com/kubernetes-sigs/cri-tools/blob/master/docs/crictl.md).

## Example crictl commands

The following examples show some `crictl` commands and example output.

### List pods

List all pods:

```shell crictl pods ```

The output is similar to this:

``` POD ID CREATED STATE NAME NAMESPACE ATTEMPT 926f1b5a1d33a About a minute ago Ready sh-84d7dcf559-4r2gq default 0 4dccb216c4adb About a minute ago Ready nginx-65899c769f-wv2gp default 0 a86316e96fa89 17 hours ago Ready kube-proxy-gblk4 kube-system 0 919630b8f81f1 17 hours ago Ready nvidia-device-plugin-zgbbv kube-system 0 ```

List pods by name:

```shell crictl pods --name nginx-65899c769f-wv2gp ```

The output is similar to this:

``` POD ID CREATED STATE NAME NAMESPACE ATTEMPT 4dccb216c4adb 2 minutes ago Ready nginx-65899c769f-wv2gp default 0 ```

List pods by label:

```shell crictl pods --label run=nginx ```

The output is similar to this:

``` POD ID CREATED STATE NAME NAMESPACE ATTEMPT 4dccb216c4adb 2 minutes ago Ready nginx-65899c769f-wv2gp default 0 ```

### List images

List all images:

```shell crictl images ```

The output is similar to this:

``` IMAGE TAG IMAGE ID SIZE busybox latest 8c811b4aec35f 1.15MB k8s-gcrio.azureedge.net/hyperkube-amd64 v1.10.3 e179bbfe5d238 665MB k8s-gcrio.azureedge.net/pause-amd64 3.1 da86e6ba6ca19 742kB nginx …(trimmed)