#!/bin/bash

# Copyright 2015 The Kubernetes Authors All rights reserved.
#
# 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.

# This script contains functions for configuring instances to run kubernetes
# master and nodes. It is uploaded as GCE instance metadata. The upstart jobs
# in cluster/gce/trusty/<node.yaml, master.yaml> download it and make use
# of needed functions. The script itself is not supposed to be executed in
# other manners.

config_hostname() {
  # Set the hostname to the short version.
  short_hostname=$(hostname -s)
  hostname $short_hostname
}

config_ip_firewall() {
  # We have seen that GCE image may have strict host firewall rules which drop
  # most inbound/forwarded packets. In such a case, add rules to accept all
  # TCP/UDP packets.
  if iptables -L INPUT | grep "Chain INPUT (policy DROP)" > /dev/null; then
    echo "Add rules to accpet all inbound TCP/UDP packets"
    iptables -A INPUT -w -p TCP -j ACCEPT
    iptables -A INPUT -w -p UDP -j ACCEPT
  fi
  if iptables -L FORWARD | grep "Chain FORWARD (policy DROP)" > /dev/null; then
    echo "Add rules to accpet all forwarded TCP/UDP packets"
    iptables -A FORWARD -w -p TCP -j ACCEPT
    iptables -A FORWARD -w -p UDP -j ACCEPT
  fi
}

create_dirs() {
  # Create required directories.
  mkdir -p /var/lib/kubelet
  mkdir -p /etc/kubernetes/manifests
  if [ "${KUBERNETES_MASTER:-}" = "false" ]; then
    mkdir -p /var/lib/kube-proxy
  fi
}

download_kube_env() {
  # Fetch kube-env from GCE metadata server.
  readonly tmp_install_dir="/var/cache/kubernetes-install"
  mkdir -p ${tmp_install_dir}
  curl --fail --silent --show-error \
    -H "X-Google-Metadata-Request: True" \
    -o "${tmp_install_dir}/kube_env.yaml" \
    http://metadata.google.internal/computeMetadata/v1/instance/attributes/kube-env
  # Convert the yaml format file into a shell-style file.
  eval $(python -c '''
import pipes,sys,yaml
for k,v in yaml.load(sys.stdin).iteritems():
  print("readonly {var}={value}".format(var = k, value = pipes.quote(str(v))))
''' < "${tmp_install_dir}/kube_env.yaml" > /etc/kube-env)
}

create_kubelet_kubeconfig() {
  # Create the kubelet kubeconfig file.
  if [ -z "${KUBELET_CA_CERT:-}" ]; then
    KUBELET_CA_CERT="${CA_CERT}"
  fi
  cat > /var/lib/kubelet/kubeconfig << EOF
apiVersion: v1
kind: Config
users:
- name: kubelet
  user:
    client-certificate-data: ${KUBELET_CERT}
    client-key-data: ${KUBELET_KEY}
clusters:
- name: local
  cluster:
    certificate-authority-data: ${KUBELET_CA_CERT}
contexts:
- context:
    cluster: local
    user: kubelet
  name: service-account-context
current-context: service-account-context
EOF
}

create_kubeproxy_kubeconfig() {
  # Create the kube-proxy config file.
  cat > /var/lib/kube-proxy/kubeconfig << EOF
apiVersion: v1
kind: Config
users:
- name: kube-proxy
  user:
    token: ${KUBE_PROXY_TOKEN}
clusters:
- name: local
  cluster:
    certificate-authority-data: ${CA_CERT}
contexts:
- context:
    cluster: local
    user: kube-proxy
  name: service-account-context
current-context: service-account-context
EOF
}

# Installs the critical packages that are required by spinning up a cluster.
install_critical_packages() {
  apt-get update
  # Install docker and brctl if they are not in the image.
  if ! which docker > /dev/null; then
    echo "Do not find docker. Install it."
    # We should install the latest qualified docker, which is version 1.8.3 at present.
    curl -sSL https://get.docker.com/ | DOCKER_VERSION=1.8.3 sh
  fi
  if ! which brctl > /dev/null; then
    echo "Do not find brctl. Install it."
    apt-get install --yes bridge-utils
  fi
}

# Install the packages that are useful but not required by spinning up a cluster.
install_additional_packages() {
  # Socat and nsenter are not required for spinning up a cluster. We move the
  # installation here to be in parallel with the cluster creation.
  if ! which socat > /dev/null; then
    echo "Do not find socat. Install it."
    apt-get install --yes socat
  fi
  if ! which nsenter > /dev/null; then
    echo "Do not find nsenter. Install it."
    # Note: this is an easy way to install nsenter, but may not be the fastest
    # way. In addition, this may not be a trusted source. So, replace it if
    # we have a better solution.
    docker run --rm -v /usr/local/bin:/target jpetazzo/nsenter
  fi
}

# Retry a download until we get it.
#
# $1 is the file to create
# $2 is the URL to download
download_or_bust() {
  rm -f $1 > /dev/null
  until curl --ipv4 -Lo "$1" --connect-timeout 20 --retry 6 --retry-delay 10 "$2"; do
    echo "Failed to download file ($2). Retrying."
  done
}

# Downloads kubernetes binaries and kube-system manifest tarball, unpacks them,
# and places them into suitable directories.
install_kube_binary_config() {
  # In anyway we have to download the release tarball as docker_tag files and
  # kube-proxy image file are there.
  cd /tmp
  k8s_sha1="${SERVER_BINARY_TAR_URL##*/}.sha1"
  echo "Downloading k8s tar sha1 file ${k8s_sha1}"
  download_or_bust "${k8s_sha1}" "${SERVER_BINARY_TAR_URL}.sha1"
  k8s_tar="${SERVER_BINARY_TAR_URL##*/}"
  echo "Downloading k8s tar file ${k8s_tar}"
  download_or_bust "${k8s_tar}" "${SERVER_BINARY_TAR_URL}"
  # Validate hash.
  actual=$(sha1sum ${k8s_tar} | awk '{ print $1 }') || true
  if [ "${actual}" != "${SERVER_BINARY_TAR_HASH}" ]; then
    echo "== ${k8s_tar} corrupted, sha1 ${actual} doesn't match expected ${SERVER_BINARY_TAR_HASH} =="
  else
    echo "Validated ${SERVER_BINARY_TAR_URL} SHA1 = ${SERVER_BINARY_TAR_HASH}"
  fi
  tar xzf "/tmp/${k8s_tar}" -C /tmp/ --overwrite
  # Copy docker_tag and image files to /run/kube-docker-files.
  mkdir -p /run/kube-docker-files
  cp /tmp/kubernetes/server/bin/*.docker_tag /run/kube-docker-files/
  if [ "${KUBERNETES_MASTER:-}" = "false" ]; then
    cp /tmp/kubernetes/server/bin/kube-proxy.tar /run/kube-docker-files/
  else
    cp /tmp/kubernetes/server/bin/kube-apiserver.tar /run/kube-docker-files/
    cp /tmp/kubernetes/server/bin/kube-controller-manager.tar /run/kube-docker-files/
    cp /tmp/kubernetes/server/bin/kube-scheduler.tar /run/kube-docker-files/
    cp -r /tmp/kubernetes/addons /run/kube-docker-files/
  fi
  # For a testing cluster, we use kubelet, kube-proxy, and kubectl binaries
  # from the release tarball and place them in /usr/local/bin. For a non-test
  # cluster, we use the binaries pre-installed in the image, or pull and place
  # them in /usr/bin if they are not pre-installed.
  BINARY_PATH="/usr/bin/"
  if [ "${TEST_CLUSTER:-}" = "true" ]; then
    BINARY_PATH="/usr/local/bin/"
  fi
  if ! which kubelet > /dev/null || ! which kube-proxy > /dev/null || [ "${TEST_CLUSTER:-}" = "true" ]; then
    cp /tmp/kubernetes/server/bin/kubelet ${BINARY_PATH}
    cp /tmp/kubernetes/server/bin/kubectl ${BINARY_PATH}
  fi
  # Clean up.
  rm -rf "/tmp/kubernetes"
  rm "/tmp/${k8s_tar}"
  rm "/tmp/${k8s_sha1}"

  # Put kube-system pods manifests in /etc/kube-manifests/.
  mkdir -p /run/kube-manifests
  cd /run/kube-manifests
  manifests_sha1="${KUBE_MANIFESTS_TAR_URL##*/}.sha1"
  echo "Downloading kube-system manifests tar sha1 file ${manifests_sha1}"
  download_or_bust "${manifests_sha1}" "${KUBE_MANIFESTS_TAR_URL}.sha1"
  manifests_tar="${KUBE_MANIFESTS_TAR_URL##*/}"
  echo "Downloading kube-manifest tar file ${manifests_tar}"
  download_or_bust "${manifests_tar}" "${KUBE_MANIFESTS_TAR_URL}"
  # Validate hash.
  actual=$(sha1sum ${manifests_tar} | awk '{ print $1 }') || true
  if [ "${actual}" != "${KUBE_MANIFESTS_TAR_HASH}" ]; then
    echo "== ${manifests_tar} corrupted, sha1 ${actual} doesn't match expected ${KUBE_MANIFESTS_TAR_HASH} =="
  else
    echo "Validated ${KUBE_MANIFESTS_TAR_URL} SHA1 = ${KUBE_MANIFESTS_TAR_HASH}"
  fi
  tar xzf "/run/kube-manifests/${manifests_tar}" -C /run/kube-manifests/ --overwrite
  rm "/run/kube-manifests/${manifests_sha1}"
  rm "/run/kube-manifests/${manifests_tar}"
}

restart_docker_daemon() {
  # Assemble docker deamon options
  DOCKER_OPTS="-p /var/run/docker.pid --bridge=cbr0 --iptables=false --ip-masq=false"
  if [ "${TEST_CLUSTER:-}" = "true" ]; then
    DOCKER_OPTS="${DOCKER_OPTS} --log-level=debug"
  fi
  echo "DOCKER_OPTS=\"${DOCKER_OPTS} ${EXTRA_DOCKER_OPTS:-}\"" > /etc/default/docker
  # Make sure the network interface cbr0 is created before restarting docker daemon
  while ! [ -L /sys/class/net/cbr0 ]; do
    echo "Sleep 1 second to wait for cbr0"
    sleep 1
  done
  initctl restart docker
  # Remove docker0
  ifconfig docker0 down
  brctl delbr docker0
}

# Create the log file and set its properties.
#
# $1 is the file to create
prepare_log_file() {
  touch $1
  chmod 644 $1
  chown root:root $1
}

# It monitors the health of several master and node components.
health_monitoring() {
  sleep_seconds=10
  max_seconds=10
  # We simply kill the process when there is a failure. Another upstart job will automatically
  # restart the process.
  while [ 1 ]; do
    if ! timeout 10 docker version > /dev/null; then
      echo "Docker daemon failed!"
      pkill docker
    fi
    if ! curl --insecure -m ${max_seconds} -f -s https://127.0.0.1:${KUBELET_PORT:-10250}/healthz > /dev/null; then
      echo "Kubelet is unhealthy!"
      pkill kubelet
    fi
    # TODO(andyzheng0831): Add master side health monitoring.
    sleep ${sleep_seconds}
  done
}


########## The functions below are for master only ##########

# Mounts a persistent disk (formatting if needed) to store the persistent data
# on the master -- etcd's data, a few settings, and security certs/keys/tokens.
# safe_format_and_mount only formats an unformatted disk, and mkdir -p will
# leave a directory be if it already exists.
mount_master_pd() {
  readonly pd_path="/dev/disk/by-id/google-master-pd"
  readonly mount_point="/mnt/disks/master-pd"

  # TODO(zmerlynn): GKE is still lagging in master-pd creation
  if [ ! -e ${pd_path} ]; then
    return
  fi
  # Format and mount the disk, create directories on it for all of the master's
  # persistent data, and link them to where they're used.
  mkdir -p ${mount_point}
  /usr/share/google/safe_format_and_mount -m "mkfs.ext4 -F" ${pd_path} ${mount_point} >/var/log/master-pd-mount.log || \
    { echo "!!! master-pd mount failed, review /var/log/master-pd-mount.log !!!"; return 1; }
  # Contains all the data stored in etcd
  mkdir -m 700 -p "${mount_point}/var/etcd"
  # Contains the dynamically generated apiserver auth certs and keys
  mkdir -p "${mount_point}/etc/srv/kubernetes"
  # Directory for kube-apiserver to store SSH key (if necessary)
  mkdir -p /"${mount_point}/etc/srv/sshproxy"
  ln -s -f "${mount_point}/var/etcd" /var/etcd
  mkdir -p /etc/srv
  ln -s -f /"${mount_point}/etc/srv/kubernetes" /etc/srv/kubernetes
  ln -s -f /"${mount_point}/etc/srv/sshproxy" /etc/srv/sshproxy

  if ! id etcd &>/dev/null; then
    useradd -s /sbin/nologin -d /var/etcd etcd
  fi
  chown -R etcd /"${mount_point}/var/etcd"
  chgrp -R etcd "${mount_point}/var/etcd"
}

# A helper function that adds an entry to a token file.
# $1: account information
# $2: token file
add_token_entry() {
  current_token=$(dd if=/dev/urandom bs=128 count=1 2>/dev/null | base64 | tr -d "=+/" | dd bs=32 count=1 2>/dev/null)
  echo "${tcurrent_token},$1,$1" >> $2
}

# After the first boot and on upgrade, these files exists on the master-pd
# and should never be touched again (except perhaps an additional service
# account, see NB below.)
create_master_auth() {
  readonly auth_dir="/etc/srv/kubernetes"
  if [ ! -e "${auth_dir}/ca.crt" ]; then
    if  [ ! -z "${CA_CERT:-}" ] && [ ! -z "${MASTER_CERT:-}" ] && [ ! -z "${MASTER_KEY:-}" ]; then
      echo "${CA_CERT}" | base64 -d > "${auth_dir}/ca.crt"
      echo "${MASTER_CERT}" | base64 -d > "${auth_dir}/server.cert"
      echo "${MASTER_KEY}" | base64 -d > "${auth_dir}/server.key"
      # Kubecfg cert/key are optional and included for backwards compatibility.
      # TODO(roberthbailey): Remove these two lines once GKE no longer requires
      # fetching clients certs from the master VM.
      echo "${KUBECFG_CERT:-}" | base64 -d > "${auth_dir}/kubecfg.crt"
      echo "${KUBECFG_KEY:-}" | base64 -d > "${auth_dir}/kubecfg.key"
    fi
  fi
  readonly basic_auth_csv="${auth_dir}/basic_auth.csv"
  if [ ! -e "${basic_auth_csv}" ]; then
    echo "${KUBE_PASSWORD},${KUBE_USER},admin" > "${basic_auth_csv}"
  fi
  readonly known_tokens_csv="${auth_dir}/known_tokens.csv"
  if [ ! -e "${known_tokens_csv}" ]; then
    echo "${KUBE_BEARER_TOKEN},admin,admin" > "${known_tokens_csv}"
    echo "${KUBELET_TOKEN},kubelet,kubelet" >> "${known_tokens_csv}"
    echo "${KUBE_PROXY_TOKEN},kube_proxy,kube_proxy" >> "${known_tokens_csv}"

    # Generate tokens for other "service accounts".  Append to known_tokens.
    #
    # NB: If this list ever changes, this script actually has to
    # change to detect the existence of this file, kill any deleted
    # old tokens and add any new tokens (to handle the upgrade case).
    add_token_entry "system:scheduler" ${known_tokens_csv}
    add_token_entry "system:controller_manager" ${known_tokens_csv}
    add_token_entry "system:logging" ${known_tokens_csv}
    add_token_entry "system:monitoring" ${known_tokens_csv}
    add_token_entry "system:dns" ${known_tokens_csv}
  fi

  if [ -n "${PROJECT_ID:-}" ] && [ -n "${TOKEN_URL:-}" ] && [ -n "${TOKEN_BODY:-}" ] && [ -n "${NODE_NETWORK:-}" ]; then
    cat <<EOF >/etc/gce.conf
[global]
token-url = ${TOKEN_URL}
token-body = ${TOKEN_BODY}
project-id = ${PROJECT_ID}
network-name = ${NODE_NETWORK}
EOF
  fi
}

# Uses KUBELET_CA_CERT (falling back to CA_CERT), KUBELET_CERT, and KUBELET_KEY
# to generate a kubeconfig file for the kubelet to securely connect to the apiserver.
create_master_kubelet_auth() {
  # Only configure the kubelet on the master if the required variables are
  # set in the environment.
  if [ -n "${KUBELET_APISERVER:-}" ] && [ -n "${KUBELET_CERT:-}" ] && [ -n "${KUBELET_KEY:-}" ]; then
    create_kubelet_kubeconfig
  fi
}

# Replaces the variables in the etcd manifest file with the real values, and then
# copy the file to the manifest dir
# $1: value for variable 'suffix'
# $2: value for variable 'port'
# $3: value for variable 'server_port'
# $4: value for variable 'cpulimit'
# $5: pod name, which should be either etcd or etcd-events
prepare_etcd_manifest() {
  readonly etcd_temp_file="/tmp/$5"
  cp /run/kube-manifests/kubernetes/trusty/etcd.manifest "${etcd_temp_file}"
  sed -i -e "s@{{ *suffix *}}@$1@g" "${etcd_temp_file}"
  sed -i -e "s@{{ *port *}}@$2@g" "${etcd_temp_file}"
  sed -i -e "s@{{ *server_port *}}@$3@g" "${etcd_temp_file}"
  sed -i -e "s@{{ *cpulimit *}}@\"$4\"@g" "${etcd_temp_file}"
  # Replace the volume host path
  sed -i -e "s@/mnt/master-pd/var/etcd@/mnt/disks/master-pd/var/etcd@g" "${etcd_temp_file}"
  mv "${etcd_temp_file}" /etc/kubernetes/manifests
}

# Starts etcd server pod (and etcd-events pod if needed).
# More specifically, it prepares dirs and files, sets the variable value
# in the manifests, and copies them to /etc/kubernetes/manifests.
start_etcd_servers() {
  if [ -d /etc/etcd ]; then
    rm -rf /etc/etcd
  fi
  if [ -e /etc/default/etcd ]; then
    rm -f /etc/default/etcd
  fi
  if [ -e /etc/systemd/system/etcd.service ]; then
    rm -f /etc/systemd/system/etcd.service
  fi
  if [ -e /etc/init.d/etcd ]; then
    rm -f /etc/init.d/etcd
  fi
  prepare_log_file /var/log/etcd.log
  prepare_etcd_manifest "" "4001" "2380" "200m" "etcd.manifest"

  # Switch on the second etcd instance if there are more than 50 nodes.
  if [ -n "${NUM_NODES:-}" ] && [ "${NUM_NODES}" -gt 50 ]; then
    prepare_log_file /var/log/etcd-events.log
    prepare_etcd_manifest "-events" "4002" "2381" "100m" "etcd-events.manifest"
  fi
}

# Calculates the following variables based on env variables, which will be used
# by the manifests of several kube-master components.
#   CLOUD_CONFIG_VOLUME
#   CLOUD_CONFIG_MOUNT
#   DOCKER_REGISTRY
compute_master_manifest_variables() {
  CLOUD_CONFIG_VOLUME=""
  CLOUD_CONFIG_MOUNT=""
  if [ -n "${PROJECT_ID:-}" ] && [ -n "${TOKEN_URL:-}" ] && [ -n "${TOKEN_BODY:-}" ] && [ -n "${NODE_NETWORK:-}" ]; then
    CLOUD_CONFIG_VOLUME="{\"name\": \"cloudconfigmount\",\"hostPath\": {\"path\": \"/etc/gce.conf\"}},"
    CLOUD_CONFIG_MOUNT="{\"name\": \"cloudconfigmount\",\"mountPath\": \"/etc/gce.conf\", \"readOnly\": true},"
  fi
  DOCKER_REGISTRY="gcr.io/google_containers"
  if [ -n "${KUBE_DOCKER_REGISTRY:-}" ]; then
    DOCKER_REGISTRY=${KUBE_DOCKER_REGISTRY}
  fi
}

# Starts k8s apiserver.
# It prepares the log file, loads the docker image, calculates variables, sets them
# in the manifest file, and then copies the manifest file to /etc/kubernetes/manifests.
#
# Assumed vars (which are calculated in function compute_master_manifest_variables)
#   CLOUD_CONFIG_VOLUME
#   CLOUD_CONFIG_MOUNT
#   DOCKER_REGISTRY
start_kube_apiserver() {
  prepare_log_file /var/log/kube-apiserver.log
  # Load the docker image from file.
  echo "Try to load docker image file kube-apiserver.tar"
  timeout 30 docker load -i /run/kube-docker-files/kube-apiserver.tar

  # Calculate variables and assemble the command line.
  params="--cloud-provider=gce --address=127.0.0.1 --etcd-servers=http://127.0.0.1:4001 --tls-cert-file=/etc/srv/kubernetes/server.cert --tls-private-key-file=/etc/srv/kubernetes/server.key --secure-port=443 --client-ca-file=/etc/srv/kubernetes/ca.crt --token-auth-file=/etc/srv/kubernetes/known_tokens.csv --basic-auth-file=/etc/srv/kubernetes/basic_auth.csv --allow-privileged=true"
  if [ -n "${NUM_NODES:-}" ] && [ "${NUM_NODES}" -gt 50 ]; then
    params="${params} --etcd-servers-overrides=/events#http://127.0.0.1:4002"
  fi
  if [ -n "${SERVICE_CLUSTER_IP_RANGE:-}" ]; then
    params="${params} --service-cluster-ip-range=${SERVICE_CLUSTER_IP_RANGE}"
  fi
  if [ -n "${ADMISSION_CONTROL:-}" ]; then
    params="${params} --admission-control=${ADMISSION_CONTROL}"
  fi
  if [ -n "${KUBE_APISERVER_REQUEST_TIMEOUT:-}" ]; then
    params="${params} --min-request-timeout=${KUBE_APISERVER_REQUEST_TIMEOUT}"
  fi
  if [ -n "${RUNTIME_CONFIG:-}" ]; then
    params="${params} --runtime-config=${RUNTIME_CONFIG}"
  fi
  if [ -n "${APISERVER_TEST_ARGS:-}" ]; then
    params="${params} ${APISERVER_TEST_ARGS}"
  fi
  log_level="--v=2"
  if [ -n "${API_SERVER_TEST_LOG_LEVEL:-}" ]; then
    log_level="${API_SERVER_TEST_LOG_LEVEL}"
  fi
  params="${params} ${log_level}"

  if [ -n "${PROJECT_ID:-}" ] && [ -n "${TOKEN_URL:-}" ] && [ -n "${TOKEN_BODY:-}" ] && [ -n "${NODE_NETWORK:-}" ]; then
    readonly vm_external_ip=$(curl --fail --silent -H 'Metadata-Flavor: Google' "http://metadata/computeMetadata/v1/instance/network-interfaces/0/access-configs/0/external-ip")
    params="${params} --cloud-config=/etc/gce.conf --advertise-address=${vm_external_ip} --ssh-user=${PROXY_SSH_USER} --ssh-keyfile=/etc/srv/sshproxy/.sshkeyfile"
  fi
  readonly kube_apiserver_docker_tag=$(cat /run/kube-docker-files/kube-apiserver.docker_tag)

  src_file="/run/kube-manifests/kubernetes/trusty/kube-apiserver.manifest"
  sed -i -e "s@{{params}}@${params}@g" ${src_file}
  sed -i -e "s@{{cloud_config_mount}}@${CLOUD_CONFIG_MOUNT}@g" ${src_file}
  sed -i -e "s@{{cloud_config_volume}}@${CLOUD_CONFIG_VOLUME}@g" ${src_file}
  sed -i -e "s@{{kube_docker_registry}}@${DOCKER_REGISTRY}@g" ${src_file}
  sed -i -e "s@{{kube-apiserver_docker_tag}}@${kube_apiserver_docker_tag}@g" ${src_file}
  cp ${src_file} /etc/kubernetes/manifests
}

# Starts k8s controller manager.
# It prepares the log file, loads the docker image, calculates variables, sets them
# in the manifest file, and then copies the manifest file to /etc/kubernetes/manifests.
#
# Assumed vars (which are calculated in function compute_master_manifest_variables)
#   CLOUD_CONFIG_VOLUME
#   CLOUD_CONFIG_MOUNT
#   DOCKER_REGISTRY
start_kube_controller_manager() {
  prepare_log_file /var/log/kube-controller-manager.log
  # Load the docker image from file.
  echo "Try to load docker image file kube-controller-manager.tar"
  timeout 30 docker load -i /run/kube-docker-files/kube-controller-manager.tar

  # Calculate variables and assemble the command line.
  params="--master=127.0.0.1:8080 --cloud-provider=gce --root-ca-file=/etc/srv/kubernetes/ca.crt --service-account-private-key-file=/etc/srv/kubernetes/server.key"
  if [ -n "${INSTANCE_PREFIX:-}" ]; then
    params="${params} --cluster-name=${INSTANCE_PREFIX}"
  fi
  if [ -n "${CLUSTER_IP_RANGE:-}" ]; then
    params="${params} --cluster-cidr=${CLUSTER_IP_RANGE}"
  fi
  if [ "${ALLOCATE_NODE_CIDRS:-}" = "true" ]; then
    params="${params} --allocate-node-cidrs=${ALLOCATE_NODE_CIDRS}"
  fi
  if [ -n "${TERMINATED_POD_GC_THRESHOLD:-}" ]; then
    params="${params} --terminated-pod-gc-threshold=${TERMINATED_POD_GC_THRESHOLD}"
  fi
  log_level="--v=2"
  if [ -n "${CONTROLLER_MANAGER_TEST_LOG_LEVEL:-}" ]; then
    log_level="${CONTROLLER_MANAGER_TEST_LOG_LEVEL}"
  fi
  params="${params} ${log_level}"
  if [ -n "${CONTROLLER_MANAGER_TEST_ARGS:-}" ]; then
    params="${params} ${CONTROLLER_MANAGER_TEST_ARGS}"
  fi
  readonly kube_rc_docker_tag=$(cat /run/kube-docker-files/kube-controller-manager.docker_tag)

  src_file="/run/kube-manifests/kubernetes/trusty/kube-controller-manager.manifest"
  sed -i -e "s@{{params}}@${params}@g" ${src_file}
  sed -i -e "s@{{cloud_config_mount}}@${CLOUD_CONFIG_MOUNT}@g" ${src_file}
  sed -i -e "s@{{cloud_config_volume}}@${CLOUD_CONFIG_VOLUME}@g" ${src_file}
  sed -i -e "s@{{kube_docker_registry}}@${DOCKER_REGISTRY}@g" ${src_file}
  sed -i -e "s@{{kube-controller-manager_docker_tag}}@${kube_rc_docker_tag}@g" ${src_file}
  cp ${src_file} /etc/kubernetes/manifests
}

# Start k8s scheduler.
# It prepares the log file, loads the docker image, calculates variables, sets them
# in the manifest file, and then copies the manifest file to /etc/kubernetes/manifests.
#
# Assumed vars (which are calculated in compute_master_manifest_variables())
#   DOCKER_REGISTRY
start_kube_scheduler() {
  prepare_log_file /var/log/kube-scheduler.log
  # Load the docker image from file.
  echo "Try to load docker image file kube-scheduler.tar"
  timeout 30 docker load -i /run/kube-docker-files/kube-scheduler.tar

  # Calculate variables and set them in the manifest.
  params=""
  log_level="--v=2"
  if [ -n "${SCHEDULER_TEST_LOG_LEVEL:-}" ]; then
    log_level="${SCHEDULER_TEST_LOG_LEVEL}"
  fi
  params="${params} ${log_level}"
  if [ -n "${SCHEDULER_TEST_ARGS:-}" ]; then
    params="${params} ${SCHEDULER_TEST_ARGS}"
  fi
  readonly kube_scheduler_docker_tag=$(cat /run/kube-docker-files/kube-scheduler.docker_tag)

  # Remove salt comments and replace variables with values
  src_file="/run/kube-manifests/kubernetes/trusty/kube-scheduler.manifest"
  sed -i "/^ *{%/d" ${src_file}
  sed -i -e "s@{{params}}@${params}@g" ${src_file}
  sed -i -e "s@{{pillar\['kube_docker_registry'\]}}@${DOCKER_REGISTRY}@g" ${src_file}
  sed -i -e "s@{{pillar\['kube-scheduler_docker_tag'\]}}@${kube_scheduler_docker_tag}@g" ${src_file}
  cp ${src_file} /etc/kubernetes/manifests
}

# Start a fluentd static pod for logging.
start_fluentd() {
  if [ "${ENABLE_NODE_LOGGING:-}" = "true" ]; then
    if [ "${LOGGING_DESTINATION:-}" = "gcp" ]; then
      cp /run/kube-manifests/kubernetes/fluentd-gcp.yaml /etc/kubernetes/manifests/
    elif [ "${LOGGING_DESTINATION:-}" = "elasticsearch" ]; then
      cp /run/kube-manifests/kubernetes/fluentd-es.yaml /etc/kubernetes/manifests/
    fi
  fi
}

# A helper function for copying addon manifests and set dir/files
# permissions.
# $1: addon category under /etc/kubernetes
# $2: manifest source dir
setup_addon_manifests() {
  src_dir="/run/kube-manifests/kubernetes/trusty/$2"
  dst_dir="/etc/kubernetes/$1/$2"
  if [ ! -d "${dst_dir}" ]; then
    mkdir -p "${dst_dir}"
  fi
  files=$(find "${src_dir}" -name "*.yaml")
  if [ -n "${files}" ]; then
    cp "${src_dir}/"*.yaml "${dst_dir}"
  fi
  files=$(find "${src_dir}" -name "*.json")
  if [ -n "${files}" ]; then
    cp "${src_dir}/"*.json "${dst_dir}"
  fi
  files=$(find "${src_dir}" -name "*.yaml.in")
  if [ -n "${files}" ]; then
    cp "${src_dir}/"*.yaml.in "${dst_dir}"
  fi
  chown -R root:root "${dst_dir}"
  chmod 755 "${dst_dir}"
  chmod 644 "${dst_dir}"/*
}

# Start k8s addons static pods.
prepare_kube_addons() {
  addon_src_dir="/run/kube-manifests/kubernetes/trusty"
  addon_dst_dir="/etc/kubernetes/addons"
  # Set up manifests of other addons.
  if [ "${ENABLE_CLUSTER_MONITORING:-}" = "influxdb" ] || \
     [ "${ENABLE_CLUSTER_MONITORING:-}" = "google" ] || \
     [ "${ENABLE_CLUSTER_MONITORING:-}" = "standalone" ] || \
     [ "${ENABLE_CLUSTER_MONITORING:-}" = "googleinfluxdb" ]; then
    file_dir="cluster-monitoring/${ENABLE_CLUSTER_MONITORING}"
    setup_addon_manifests "addons" "${file_dir}"
    # Replace the salt configurations with variable values.
    heapster_memory="200Mi"
    if [ -n "${NUM_NODES:-}" ] && [ "${NUM_NODES}" -gt 1 ]; then
      heapster_memory="$((${NUM_NODES} * 3 + 200))Mi"
    fi
    controller_yaml="${addon_dst_dir}/${file_dir}"
    if [ "${ENABLE_CLUSTER_MONITORING:-}" = "googleinfluxdb" ]; then
      controller_yaml="${controller_yaml}/heapster-controller-combined.yaml"
    else
      controller_yaml="${controller_yaml}/heapster-controller.yaml"
    fi
    sed -i "/^ *{%/d" "${controller_yaml}"
    sed -i -e "s@{{ *heapster_memory *}}@${heapster_memory}@g" "${controller_yaml}"
  fi
  cp "${addon_src_dir}/namespace.yaml" "${addon_dst_dir}"
  if [ "${ENABLE_L7_LOADBALANCING:-}" = "glbc" ]; then
    setup_addon_manifests "addons" "cluster-loadbalancing/glbc"
  fi
  if [ "${ENABLE_CLUSTER_DNS:-}" = "true" ]; then
    setup_addon_manifests "addons" "dns"
    dns_rc_file="${addon_dst_dir}/dns/skydns-rc.yaml"
    dns_svc_file="${addon_dst_dir}/dns/skydns-svc.yaml"
    mv "${addon_dst_dir}/dns/skydns-rc.yaml.in" "${dns_rc_file}"
    mv "${addon_dst_dir}/dns/skydns-svc.yaml.in" "${dns_svc_file}"
    # Replace the salt configurations with variable values.
    sed -i -e "s@{{ *pillar\['dns_replicas'\] *}}@${DNS_REPLICAS}@g" "${dns_rc_file}"
    sed -i -e "s@{{ *pillar\['dns_domain'\] *}}@${DNS_DOMAIN}@g" "${dns_rc_file}"
    sed -i -e "s@{{ *pillar\['dns_server'\] *}}@${DNS_SERVER_IP}@g" "${dns_svc_file}"
  fi
  if [ "${ENABLE_CLUSTER_REGISTRY:-}" = "true" ]; then
    setup_addon_manifests "addons" "registry"
    registry_pv_file="${addon_dst_dir}/registry/registry-pv.yaml"
    registry_pvc_file="${addon_dst_dir}/registry/registry-pvc.yaml"
    mv "${addon_dst_dir}/registry/registry-pv.yaml.in" "${registry_pv_file}"
    mv "${addon_dst_dir}/registry/registry-pvc.yaml.in" "${registry_pvc_file}"
    # Replace the salt configurations with variable values.
    sed -i "/^ *{%/d" "${registry_pv_file}"
    sed -i -e "s@{{ *pillar\['cluster_registry_disk_size'\] *}}@${CLUSTER_REGISTRY_DISK_SIZE}@g" "${registry_pv_file}"
    sed -i -e "s@{{ *pillar\['cluster_registry_disk_size'\] *}}@${CLUSTER_REGISTRY_DISK_SIZE}@g" "${registry_pvc_file}"
    sed -i -e "s@{{ *pillar\['cluster_registry_disk_name'\] *}}@${CLUSTER_REGISTRY_DISK}@g" "${registry_pvc_file}"
  fi
  if [ "${ENABLE_NODE_LOGGING:-}" = "true" ] && \
     [ "${LOGGING_DESTINATION:-}" = "elasticsearch" ] && \
     [ "${ENABLE_CLUSTER_LOGGING:-}" = "true" ]; then
    setup_addon_manifests "addons" "fluentd-elasticsearch"
  fi
  if [ "${ENABLE_CLUSTER_UI:-}" = "true" ]; then
    setup_addon_manifests "addons" "dashboard"
  fi
  if echo "${ADMISSION_CONTROL:-}" | grep -q "LimitRanger"; then
    setup_addon_manifests "admission-controls" "limit-range"
  fi

  # Prepare the scripts for running addons.
  addon_script_dir="/var/lib/cloud/scripts/kubernetes"
  mkdir -p "${addon_script_dir}"
  cp "${addon_src_dir}/kube-addons.sh" "${addon_script_dir}"
  cp "${addon_src_dir}/kube-addon-update.sh" "${addon_script_dir}"
  chmod 544 "${addon_script_dir}/"*.sh
  # In case that some GCE customized trusty may have a read-only /root.
  mount -t tmpfs tmpfs /root
  mount --bind -o remount,rw,noexec /root
}