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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-17.12.0-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} 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}"