Monitoring Google App Engine

Clone the repository

git clone 'https://github.com/instana/instana-agent-docker.git'

cd instana-agent-docker

Modification to support Java

To support running Java based apps, the Dockerfile must be modified and it has to contain:

• All variables needed by the Instana agent, like your agent key or the host agent endpoint.
• Instana agent repository configuration
• Java installation
• Instana agent configuration files
• replace java_app_name.jar with your application
• update main-process script for running Java application

FROM alpine:3.7

ENV LANG=C.UTF-8 \
    INSTANA_AGENT_KEY="" \
    INSTANA_AGENT_ENDPOINT="" \
    INSTANA_AGENT_ENDPOINT_PORT="" \
    INSTANA_AGENT_ZONE="" \
    INSTANA_AGENT_TAGS="" \
    INSTANA_AGENT_HTTP_LISTEN="" \
    INSTANA_AGENT_PROXY_HOST="" \
    INSTANA_AGENT_PROXY_PORT="" \
    INSTANA_AGENT_PROXY_PROTOCOL="" \
    INSTANA_AGENT_PROXY_USER="" \
    INSTANA_AGENT_PROXY_PASSWORD="" \
    INSTANA_AGENT_PROXY_USE_DNS=""

RUN echo "@edge http://dl-cdn.alpinelinux.org/alpine/edge/community" >> /etc/apk/repositories && \
    apk update && \
    apk upgrade && \
    apk add --update-cache --update gomplate@edge bash ca-certificates curl docker@edge inotify-tools && \
    curl -sSL https://packages.instana.io/Instana.rsa -o /etc/apk/keys/instana.rsa.pub && \
    echo "https://_:YOUR_INSTANA_AGENT_HERE@packages.instana.io/agent/apk/generic" >> /etc/apk/repositories && \
    apk update && \
    apk add instana-agent-dynamic && \
    ( /usr/glibc-compat/bin/localedef --force --inputfile POSIX --charmap UTF-8 C.UTF-8 || true ) && \
    echo "export LANG=C.UTF-8" > /etc/profile.d/locale.sh && \
    sed -i '$d' /etc/apk/repositories && \
    rm -rf /tmp/* /var/cache/apk/*

# Install OpenJDK-8
RUN apk update && \
    apk --update add openjdk8-jre

ADD org.ops4j.pax.logging.cfg /root/
ADD org.ops4j.pax.url.mvn.cfg /root/
ADD configuration.yaml /root/
ADD com.instana.agent.main.sender.Backend.cfg.tmpl /root/
ADD mvn-settings.xml.tmpl /root/

# This is the run.sh from the repository renamed to instana-agent
ADD instana-agent /root

# Add the jar file and main-process
ADD java_app_name.jar /root
ADD main-process /root

# The wrapper is used to run both processes in the same container
COPY wrapper.sh /root

WORKDIR /root

ENTRYPOINT ["./wrapper.sh"]

Rename run.sh to instana-agent.

Create a new file called main-process and add this content to it:

java -jar /root/java_app_name.jar &

Create wrapper.sh file:

#!/bin/bash

# Start the first process

./main-process -D
status=$?
if [ $status -ne 0 ]; then
  echo "Failed to start main-process: $status"
  exit $status
fi

# Start the second process
./instana-agent -D
status=$?
if [ $status -ne 0 ]; then
  echo "Failed to start instana-agent: $status"
  exit $status
fi

while sleep 60; do
  ps aux |grep main-process |grep -q -v grep
  PROCESS_1_STATUS=$?
  ps aux |grep instana-agent |grep -q -v grep
  PROCESS_2_STATUS=$?
  # If the greps above find anything, they exit with 0 status
  # If they are not both 0, then something is wrong
  if [ $PROCESS_1_STATUS -ne 0 -o $PROCESS_2_STATUS -ne 0 ]; then
    echo "One of the processes has already exited."
    exit 1
  fi
done

Modification to support NodeJS

The process is similar to Java applications. Instead of Java, install NodeJS and the npm package @instana/collector:

ADD package.json /root
ADD app.js /root/

# Install NodeJS
RUN apk update && \
    apk --update add nodejs nodejs-npm
RUN npm install --save @instana/collector

The main-process file needs instruction how to run your NodeJS app:

node app.js &

Your application also needs to require and initialize the @instana/collector package, for details on that refer to our documentation on Node.js.

Summary

• The Instana agent key must be placed in the Dockerfile in order to install the host agent
• main-process is used to start the Java process
• instana-agent is used to start the Instana agent process (renamed from run.sh)
• The wrapper is used to start both processes