--- reviewers: - Random-Liu - feiskyer - mrunalp title: Debugging Kubernetes nodes with crictl content_type: task weight: 30 --- {{< feature-state for_k8s_version="v1.11" state="stable" >}} `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. ## {{% heading "prerequisites" %}} `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 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 latest cd5239a0906a6 109MB ``` List images by repository: ```shell crictl images nginx ``` The output is similar to this: ``` IMAGE TAG IMAGE ID SIZE nginx latest cd5239a0906a6 109MB ``` Only list image IDs: ```shell crictl images -q ``` The output is similar to this: ``` sha256:8c811b4aec35f259572d0f79207bc0678df4c736eeec50bc9fec37ed936a472a sha256:e179bbfe5d238de6069f3b03fccbecc3fb4f2019af741bfff1233c4d7b2970c5 sha256:da86e6ba6ca197bf6bc5e9d900febd906b133eaa4750e6bed647b0fbe50ed43e sha256:cd5239a0906a6ccf0562354852fae04bc5b52d72a2aff9a871ddb6bd57553569 ``` ### List containers List all containers: ```shell crictl ps -a ``` The output is similar to this: ``` CONTAINER ID IMAGE CREATED STATE NAME ATTEMPT 1f73f2d81bf98 busybox@sha256:141c253bc4c3fd0a201d32dc1f493bcf3fff003b6df416dea4f41046e0f37d47 7 minutes ago Running sh 1 9c5951df22c78 busybox@sha256:141c253bc4c3fd0a201d32dc1f493bcf3fff003b6df416dea4f41046e0f37d47 8 minutes ago Exited sh 0 87d3992f84f74 nginx@sha256:d0a8828cccb73397acb0073bf34f4d7d8aa315263f1e7806bf8c55d8ac139d5f 8 minutes ago Running nginx 0 1941fb4da154f k8s-gcrio.azureedge.net/hyperkube-amd64@sha256:00d814b1f7763f4ab5be80c58e98140dfc69df107f253d7fdd714b30a714260a 18 hours ago Running kube-proxy 0 ``` List running containers: ```shell crictl ps ``` The output is similar to this: ``` CONTAINER ID IMAGE CREATED STATE NAME ATTEMPT 1f73f2d81bf98 busybox@sha256:141c253bc4c3fd0a201d32dc1f493bcf3fff003b6df416dea4f41046e0f37d47 6 minutes ago Running sh 1 87d3992f84f74 nginx@sha256:d0a8828cccb73397acb0073bf34f4d7d8aa315263f1e7806bf8c55d8ac139d5f 7 minutes ago Running nginx 0 1941fb4da154f k8s-gcrio.azureedge.net/hyperkube-amd64@sha256:00d814b1f7763f4ab5be80c58e98140dfc69df107f253d7fdd714b30a714260a 17 hours ago Running kube-proxy 0 ``` ### Execute a command in a running container ```shell crictl exec -i -t 1f73f2d81bf98 ls ``` The output is similar to this: ``` bin dev etc home proc root sys tmp usr var ``` ### Get a container's logs Get all container logs: ```shell crictl logs 87d3992f84f74 ``` The output is similar to this: ``` 10.240.0.96 - - [06/Jun/2018:02:45:49 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.47.0" "-" 10.240.0.96 - - [06/Jun/2018:02:45:50 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.47.0" "-" 10.240.0.96 - - [06/Jun/2018:02:45:51 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.47.0" "-" ``` Get only the latest `N` lines of logs: ```shell crictl logs --tail=1 87d3992f84f74 ``` The output is similar to this: ``` 10.240.0.96 - - [06/Jun/2018:02:45:51 +0000] "GET / HTTP/1.1" 200 612 "-" "curl/7.47.0" "-" ``` ## {{% heading "whatsnext" %}} * [Learn more about `crictl`](https://github.com/kubernetes-sigs/cri-tools).