Created
August 7, 2018 15:05
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#!/bin/bash | |
# Copyright 2017 The Kubernetes Authors. | |
# | |
# Licensed under the Apache License, Version 2.0 (the "License"); | |
# you may not use this file except in compliance with the License. | |
# You may obtain a copy of the License at | |
# | |
# http://www.apache.org/licenses/LICENSE-2.0 | |
# | |
# Unless required by applicable law or agreed to in writing, software | |
# distributed under the License is distributed on an "AS IS" BASIS, | |
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
# See the License for the specific language governing permissions and | |
# limitations under the License. | |
set -o nounset | |
set -o errexit | |
set -o pipefail | |
# Customizable parameters | |
TMP_SUBDIR="${TMP_SUBDIR:-debug-tools}" | |
CONTEXT="${KUBECONTEXT:-}" | |
ARCH="${ARCH:-amd64}" | |
DOCKER_DOWNLOAD_URL="${DOCKER_DOWNLOAD_URL:-https://download.docker.com/linux/static/stable/x86_64/docker-18.06.0-ce.tgz}" | |
# Parse arguments & flags | |
while [[ $# -gt 0 ]]; do | |
case $1 in | |
-n|--namespace) | |
NAMESPACE=$2 | |
shift | |
;; | |
-c|--container) | |
CONTAINER_NAME=$2 | |
shift | |
;; | |
*) | |
NAME=$1 | |
;; | |
esac | |
shift | |
done | |
if [[ -z ${NAME:-} ]]; then | |
echo >&2 "USAGE: $0 POD_NAME [-n POD_NAMESPACE] [-c CONTAINER_NAME]" | |
exit 1 | |
fi | |
# Internal variables | |
KUBECTL="kubectl" | |
[ -z "${CONTEXT}" ] || KUBECTL="${KUBECTL} --context=${CONTEXT}" | |
[ -z "${NAMESPACE:-}" ] || KUBECTL="${KUBECTL} --namespace=${NAMESPACE}" | |
NAMESPACE=${NAMESPACE:-default} | |
TARGET_CNAME=${CONTAINER_NAME:-} | |
if [ -z "${CONTAINER_NAME:-}" ]; then | |
CONTAINER_NAME=$(${KUBECTL} get pod ${NAME} -o jsonpath='{.spec.containers[0].name}') | |
fi | |
INSTALL_DIR="/tmp/${TMP_SUBDIR}" | |
CONTAINER_ID=$(${KUBECTL} get pod ${NAME} -o jsonpath="{.status.containerStatuses[?(@.name==\"${CONTAINER_NAME}\")].containerID}") | |
RUNTIME=${CONTAINER_ID%://*} | |
CONTAINER_ID=${CONTAINER_ID#*://} | |
NODE=$(${KUBECTL} get pod ${NAME} -o jsonpath='{.spec.nodeName}') | |
if [[ ${RUNTIME} != docker ]]; then | |
echo >&2 "Error: $0 only works with a docker runtime. Found: ${CONTAINER_ID}" | |
exit 1 | |
fi | |
# Construct the command to debug the target container. | |
DEBUG_CMD="${KUBECTL} exec -i -t ${NAME}" | |
[ -z "${TARGET_CNAME}" ] || DEBUG_CMD="${DEBUG_CMD} -c ${TARGET_CNAME}" | |
DEBUG_CMD="${DEBUG_CMD} -- ${INSTALL_DIR}/sh -c 'PATH=\${PATH}:${INSTALL_DIR} sh'" | |
if ${KUBECTL} exec ${NAME} -c ${CONTAINER_NAME} -- ${INSTALL_DIR}/echo &>/dev/null; then | |
echo "Debug tools already installed. Dumping you into the pod container now." | |
eval "${DEBUG_CMD}" | |
exit 0 | |
fi | |
cat <<EOF | |
Debug Target Container: | |
Pod: ${NAME} | |
Namespace: ${NAMESPACE} | |
Node: ${NODE} | |
Container: ${CONTAINER_NAME} | |
Container ID: ${CONTAINER_ID} | |
Runtime: ${RUNTIME} | |
"Installing busybox to ${INSTALL_DIR} ..." | |
EOF | |
case ${ARCH} in | |
"amd64") | |
IMAGE=busybox | |
;; | |
"arm") | |
IMAGE=armhf/busybox | |
;; | |
"arm64") | |
IMAGE=aarch64/busybox | |
;; | |
"ppc64le") | |
IMAGE=ppc64le/busybox | |
;; | |
"s390x") | |
IMAGE=s390x/busybox | |
;; | |
*) | |
echo "Unsupported architecture: ${ARCH}" | |
exit 1 | |
esac | |
DOCKERCMD="/docker-cli/docker/docker -H unix:///mnt/docker.sock" | |
# Command for installing busybox image from the debugger container into the target container. | |
INSTALLCMD="set -x;" # Print commands, for debugging. | |
# Download docker client | |
INSTALLCMD="${INSTALLCMD} mkdir /docker-cli" | |
# Download docker client | |
INSTALLCMD="${INSTALLCMD} && wget -qO/docker-cli/docker.tgz ${DOCKER_DOWNLOAD_URL}" | |
# Extract docker client | |
INSTALLCMD="${INSTALLCMD} && tar zxvf /docker-cli/docker.tgz -C /docker-cli" | |
# Create the directory structure for the install. | |
INSTALLCMD="${INSTALLCMD} && mkdir -p ${INSTALL_DIR}" | |
# Copy the directory structure into the target container. | |
INSTALLCMD="${INSTALLCMD} && ${DOCKERCMD} cp /tmp ${CONTAINER_ID}:/" | |
# Copy the busybox binary into the install location. | |
INSTALLCMD="${INSTALLCMD} && ${DOCKERCMD} cp /bin/busybox ${CONTAINER_ID}:${INSTALL_DIR}/busybox" | |
# Tell busybox to install (create symlinks for commands) into the install directory. | |
INSTALLCMD="${INSTALLCMD} && ${DOCKERCMD} exec ${CONTAINER_ID} ${INSTALL_DIR}/busybox --install -s ${INSTALL_DIR}" | |
DEBUGGER_NAME=$(${KUBECTL} create -o name -f - <<EOF | |
apiVersion: v1 | |
kind: Pod | |
metadata: | |
generateName: debugger- | |
namespace: ${NAMESPACE} | |
spec: | |
nodeName: ${NODE} | |
restartPolicy: Never | |
containers: | |
- name: debugger | |
image: ${IMAGE} | |
securityContext: | |
privileged: true | |
command: | |
- sh | |
- -c | |
- "${INSTALLCMD}" | |
# Mount the node FS for direct access to docker. | |
volumeMounts: | |
- name: docker-sock | |
mountPath: /mnt/docker.sock | |
readOnly: true | |
volumes: | |
- name: docker-sock | |
hostPath: | |
path: /var/run/docker.sock | |
EOF | |
) | |
DEBUGGER_NAME=${DEBUGGER_NAME#pod/} # Remove pod/ prefix from name | |
# Cleanup the debugger pod. | |
function cleanup() { | |
if ${KUBECTL} get pod ${DEBUGGER_NAME} &>/dev/null; then | |
${KUBECTL} delete pod ${DEBUGGER_NAME} | |
fi | |
} | |
trap cleanup EXIT | |
# Wait for the pod to terminate. | |
PHASE=$(${KUBECTL} get pod -a ${DEBUGGER_NAME} -o jsonpath='{.status.phase}') | |
while [[ ! ${PHASE} =~ (Succeeded|Failed) ]]; do | |
echo "waiting for debugger pod to complete (currently ${PHASE})..." | |
sleep 1 | |
PHASE=$(${KUBECTL} get pod -a ${DEBUGGER_NAME} -o jsonpath='{.status.phase}') | |
done | |
if [[ ${PHASE} == "Failed" ]]; then | |
echo 2> "Pod failed:" | |
${KUBECTL} logs ${DEBUGGER_NAME} | |
exit 1 | |
fi | |
cleanup | |
echo "Installation complete." | |
echo "To debug ${NAME}, run: | |
${DEBUG_CMD} | |
Dumping you into the pod container now. | |
" | |
eval "${DEBUG_CMD}" |
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