├── LICENSE ├── README.md ├── k9s-plugin.yaml ├── kubectl-node_shell └── test.sh /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. Definitions. 8 | 9 | "License" shall mean the terms and conditions for use, reproduction, 10 | and distribution as defined by Sections 1 through 9 of this document. 11 | 12 | "Licensor" shall mean the copyright owner or entity authorized by 13 | the copyright owner that is granting the License. 14 | 15 | "Legal Entity" shall mean the union of the acting entity and all 16 | other entities that control, are controlled by, or are under common 17 | control with that entity. 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Uses an alpine pod with nsenter for Linux nodes and a [HostProcess pod](https://kubernetes.io/docs/tasks/configure-pod-container/create-hostprocess-pod/) with PowerShell for Windows nodes. 5 | 6 | ![demo](https://gist.githubusercontent.com/kvaps/2e3d77975a844654ec297893e21a0829/raw/c778a8405ff8c686e4e807a97e9721b423e7208f/kubectl-node-shell.gif) 7 | 8 | ## Installation 9 | 10 | using [krew](https://krew.sigs.k8s.io/): 11 | 12 | Plugin can be installed from the official krew repository: 13 | 14 | 
 15 | kubectl krew install node-shell
 16 |
17 | 18 | Or from our own krew repository: 19 | 
 20 | kubectl krew index add kvaps https://github.com/kvaps/krew-index
 21 | kubectl krew install kvaps/node-shell
 22 |
23 | 24 | or using curl: 25 | 26 | ```bash 27 | curl -LO https://github.com/kvaps/kubectl-node-shell/raw/master/kubectl-node_shell 28 | chmod +x ./kubectl-node_shell 29 | sudo mv ./kubectl-node_shell /usr/local/bin/kubectl-node_shell 30 | ``` 31 | 32 | ## Usage 33 | 34 | ```bash 35 | # Get standard bash shell 36 | kubectl node-shell 37 | 38 | # Use custom image for pod 39 | kubectl node-shell --image 40 | 41 | # Use X-mode (mount /host, and do not enter host namespace) 42 | kubectl node-shell -x 43 | 44 | # Skip specific namespace types to enter, choose any of ipc, mount, pid, net, uts 45 | kubectl node-shell --no-ipc 46 | 47 | # Execute custom command 48 | kubectl node-shell -- echo 123 49 | 50 | # Use stdin 51 | cat /etc/passwd | kubectl node-shell -- sh -c 'cat > /tmp/passwd' 52 | 53 | # Run oneliner script 54 | kubectl node-shell -- sh -c 'cat /tmp/passwd; rm -f /tmp/passwd' 55 | ``` 56 | 57 | ## X-mode 58 | 59 | X-mode can be useful for debugging minimal systems that do not have a built-in shell (eg. Talos). 60 | Here's an example of how you can debug the network for a rootless kube-apiserver container without a filesystem: 61 | 62 | ```bash 63 | kubectl node-shell -x 64 | 65 | # Download crictl 66 | wget https://github.com/kubernetes-sigs/cri-tools/releases/download/v1.28.0/crictl-v1.28.0-linux-amd64.tar.gz -O- | \ 67 | tar -xzf- -C /usr/local/bin/ 68 | 69 | # Setup CRI endpoint 70 | export CONTAINER_RUNTIME_ENDPOINT=unix:///host/run/containerd/containerd.sock 71 | 72 | # Find your container 73 | crictl ps | grep kube-apiserver 74 | #3ff4626a9f10e e7972205b6614 6 hours ago Running kube-apiserver 0 215107b47bd7e kube-apiserver-talos-rzq-nkg 75 | 76 | # Find pid of the container 77 | crictl inspect 3ff4626a9f10e | grep pid 78 | # "pid": 2152, 79 | # "pid": 1 80 | # "type": "pid" 81 | # "getpid", 82 | # "getppid", 83 | # "pidfd_open", 84 | # "pidfd_send_signal", 85 | # "waitpid", 86 | 87 | # Go to network namespace of the pid, but keep mount namespace of the debug container 88 | nsenter -t 2152 -n 89 | ``` 90 | 91 | *You need to be able to start privileged containers for that.* 92 | 93 | ## Mounting External CSI Volumes 94 | 95 | You can mount volumes from your CSI storage layer using the `-m` flag. This allows you to move data to/from node devices seamlessly. The PVC will be mounted at `/opt-pvc`. This is useful for failover in minimal systems that do not have a built in shell (eg. Talos). 96 | Here is an example of how you can retrieve zfs/lvm data from a volume on a failed CSI node and put it back in your distributed storage layer: 97 | 98 | ```bash 99 | k node-shell -n -x -m 100 | 101 | # install rsync 102 | apk add rsync 103 | 104 | # Add lvm/zfs libs 105 | # ZFS 106 | mount -o bind /host/dev /dev 107 | mount -o bind /host/usr/local /usr/local 108 | touch /lib/libuuid.so.1 109 | mount -o bind /host/lib/libuuid.so.1 /lib/libuuid.so.1 110 | touch /lib/libuuid.so.1.3.0 111 | mount -o bind /host/lib/libuuid.so.1.3.0 /lib/libuuid.so.1.3.0 112 | touch /lib/libblkid.so.1 113 | mount -o bind /host/lib/libblkid.so.1 /lib/libblkid.so.1 114 | touch /lib/libblkid.so.1.1.0 115 | mount -o bind /host/lib/libblkid.so.1.1.0 /lib/libblkid.so.1.1.0 116 | #LVM 117 | touch /usr/lib/libaio.so.1 118 | mount -o bind /host/usr/lib/libaio.so.1.0.2 /usr/lib/libaio.so.1 119 | touch /usr/lib/libudev.so.1 120 | mount -o bind /host/usr/lib/libudev.so.1 /usr/lib/libudev.so.1 121 | export PATH=$PATH:/host/sbin 122 | mkdir /lib/modules 123 | mount -o bind /host/lib/modules /lib/modules 124 | 125 | # look for data to recover 126 | zfs list 127 | NAME USED AVAIL REFER MOUNTPOINT 128 | hdd-1 15.9T 7.52T 96K /hdd-1 129 | hdd-1/SOME-OLD-PVC-FROM-PREVIOUS-NODE-INSTALL 361G 7.52T 361G - - 130 | 131 | # mount the failed volume 132 | zfs set mountpoint=/mnt hdd-1/SOME-OLD-PVC-FROM-PREVIOUS-NODE-INSTALL 133 | zfs mount /hdd-1/SOME-OLD-PVC-FROM-PREVIOUS-NODE-INSTALL 134 | 135 | # recover the data : copy it to the mounted CSI volume 136 | rsync -avh --info=progress2 /mnt/ /opt-pvc/ 137 | ``` 138 | 139 | the above exemple assumes `pvc_name` already exists in `namespace`. *You need to be able to start privileged containers.* -------------------------------------------------------------------------------- /k9s-plugin.yaml: -------------------------------------------------------------------------------- 1 | plugins: 2 | node-shell: 3 | shortCut: Ctrl-N 4 | description: "Open a root shell on a node using the node-shell plugin" 5 | scopes: 6 | - nodes 7 | command: kubectl 8 | args: 9 | - node-shell 10 | - $NAME 11 | - --context 12 | - $CONTEXT 13 | background: false 14 | confirm: false 15 | -------------------------------------------------------------------------------- /kubectl-node_shell: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env sh 2 | set -e 3 | 4 | kubectl=kubectl 5 | version=1.11.0 6 | generator="" 7 | node="" 8 | nodefaultctx=0 9 | nodefaultns=0 10 | container_cpu="${KUBECTL_NODE_SHELL_POD_CPU:-100m}" 11 | container_memory="${KUBECTL_NODE_SHELL_POD_MEMORY:-256Mi}" 12 | volumes="[]" 13 | volume_mounts="[]" 14 | x_mode=false 15 | labels="${KUBECTL_NODE_SHELL_LABELS}" 16 | pod_running_timeout="${KUBECTL_NODE_SHELL_POD_RUNNING_TIMEOUT:-1m}" 17 | image_pull_secret_name="${KUBECTL_NODE_SHELL_IMAGE_PULL_SECRET_NAME}" 18 | custom_image="" 19 | use_ipc=true 20 | use_mount=true 21 | use_pid=true 22 | use_net=true 23 | use_uts=true 24 | 25 | if [ -t 0 ]; then 26 | tty=true 27 | else 28 | tty=false 29 | fi 30 | while [ $# -gt 0 ]; do 31 | key="$1" 32 | 33 | case $key in 34 | -v | --version) 35 | echo "kubectl-node-shell $version" 36 | exit 0 37 | ;; 38 | --context) 39 | nodefaultctx=1 40 | kubectl="$kubectl --context $2" 41 | shift 42 | shift 43 | ;; 44 | --kubecontext=*) 45 | nodefaultctx=1 46 | kubectl="$kubectl --context=${key##*=}" 47 | shift 48 | ;; 49 | --kubeconfig) 50 | kubectl="$kubectl --kubeconfig $2" 51 | shift 52 | shift 53 | ;; 54 | --kubeconfig=*) 55 | kubectl="$kubectl --kubeconfig=${key##*=}" 56 | shift 57 | ;; 58 | -n | --namespace) 59 | nodefaultns=1 60 | kubectl="$kubectl --namespace $2" 61 | shift 62 | shift 63 | ;; 64 | --namespace=*) 65 | nodefaultns=1 66 | kubectl="$kubectl --namespace=${key##*=}" 67 | shift 68 | ;; 69 | -m | --mount) 70 | volumes=$(echo "$volumes" | jq '. += [{"persistentVolumeClaim": {"claimName": "'"$2"'", "type": ""}, "name": "'"pvc"'"}]') 71 | volume_mounts=$(echo "$volume_mounts" | jq '. += [{"mountPath": "/opt-pvc", "name": "'"pvc"'"}]') 72 | shift 73 | shift 74 | ;; 75 | -x) 76 | x_mode=true 77 | volumes=$(echo "$volumes" | jq '. += [{"hostPath": {"path": "/", "type": ""}, "name": "host-root"}]') 78 | volume_mounts=$(echo "$volume_mounts" | jq '. += [{"mountPath":"/host","name":"host-root"}]') 79 | shift 80 | ;; 81 | --image) 82 | custom_image="$2" 83 | shift 84 | shift 85 | ;; 86 | --no-ipc) 87 | use_ipc=false 88 | shift 89 | ;; 90 | --no-mount) 91 | use_mount=false 92 | shift 93 | ;; 94 | --no-pid) 95 | use_pid=false 96 | shift 97 | ;; 98 | --no-net) 99 | use_net=false 100 | shift 101 | ;; 102 | --no-uts) 103 | use_uts=false 104 | shift 105 | ;; 106 | --) 107 | shift 108 | break 109 | ;; 110 | *) 111 | if [ -z "$node" ]; then 112 | node="${1#node/}" 113 | shift 114 | else 115 | echo "exactly one node required" 116 | exit 1 117 | fi 118 | ;; 119 | esac 120 | done 121 | 122 | if [ -z "$node" ]; then 123 | echo "Please specify node name" 124 | exit 1 125 | fi 126 | 127 | if [ -z "$KUBERNETES_PORT" ]; then 128 | # Set the default context and namespace to avoid situations where the user switch them during the build process 129 | [ "$nodefaultctx" = 1 ] || kubectl="$kubectl --context=$(${kubectl} config current-context)" 130 | [ "$nodefaultns" = 1 ] || kubectl="$kubectl --namespace=$(${kubectl} config view --minify --output 'jsonpath={.contexts..namespace}')" 131 | fi 132 | 133 | # Check the node and retrieve the node OS label 134 | os="$($kubectl get node $node -o jsonpath="{.metadata.labels.kubernetes\.io/os}" || exit 1)" 135 | 136 | # Set pod configuration per operating system 137 | if [ "$os" = "windows" ]; then 138 | default_image="mcr.microsoft.com/oss/kubernetes/windows-host-process-containers-base-image:v1.0.0" 139 | image="${custom_image:-${KUBECTL_NODE_SHELL_IMAGE_WINDOWS:-$default_image}}" 140 | name="pwsh" 141 | pod="${name}-$(env LC_ALL=C tr -dc a-z0-9 &1 | grep -q 'failed quota' || resources_json='"resources": {}' 204 | 205 | if [ -n "${image_pull_secret_name}" ]; then 206 | image_pull_secrets='[ { "name": "'${image_pull_secret_name}'" } ]' 207 | else 208 | image_pull_secrets='null' 209 | fi 210 | 211 | overrides="$( 212 | cat <&2 || true; exit \$EC" EXIT INT TERM 249 | 250 | echo "spawning \"$pod\" on \"$node\"" >&2 251 | $kubectl run --image "$image" --restart=Never --overrides="$overrides" --labels="$labels" --pod-running-timeout="$pod_running_timeout" $([ "$tty" = true ] && echo -t) -i "$pod" $generator 252 | -------------------------------------------------------------------------------- /test.sh: -------------------------------------------------------------------------------- 1 | #!/bin/bash 2 | run_test() { 3 | local name=$1 4 | local node=$2 5 | local script=$3 6 | echo "==== test: $1 (node: $2) ====" 7 | 8 | local expected="$(mktemp)" 9 | local got="$(mktemp)" 10 | 11 | if diff --strip-trailing-cr -u <(sh -c "$script") <(set -x; ./kubectl-node_shell $node -- sh -c "$script"); then 12 | echo -e "Result: \e[42mPASS\e[49m" 13 | else 14 | echo -e "Result: \e[101mFAIL\e[49m" 15 | fi 16 | 17 | rm -f "$expected" "$got" 18 | } 19 | 20 | if [ -z $1 ]; then 21 | echo "please specify node in first argument" >&2 22 | exit -1 23 | fi 24 | 25 | case=() 26 | 27 | case[1]=$(cat <<\EOT 28 | echo $(echo " 29 | hello everybody 30 | I'm a \"baby seal\"" 31 | 32 | ) 33 | EOT 34 | ) 35 | 36 | case[2]=$(cat <<\EOT 37 | 38 | echo "ggg 39 | 40 | 41 | ttt" 42 | EOT 43 | ) 44 | 45 | case[3]=$(cat <<\EOT 46 | echo $(echo " 47 | hello everybody 48 | I'm a \"baby seal 49 | 50 | really really 51 | 52 | \"" 53 | ) 54 | EOT 55 | ) 56 | 57 | case[4]="$(echo -e echo "\e[42mHOLA\e[49m")" 58 | 59 | for i in $(seq 1 ${#case[@]}); do 60 | run_test "case $i" "$1" "${case[$i]}" 61 | done 62 | --------------------------------------------------------------------------------