Summary 

This document contains step-by-step flow how to effectively and fast take a heap dump from folio modules.

Benefits of new approach:

• Faster
• less steps
• No need to do multiple SCPs from different instances as heap dump will go strait to S3 bucket
• Can be automated in future

Flow

1. Check EC2 instance where particular docker container is located by clicking on service task in ECS service:

2. Connect to EC2 instance via SSH with command like

ssh -i "folio-int.pem" ec2-user@{IP}

3. Do Docker ps and grab id of needed container;

4. SSH inside container by command 

docker exec -it {dockerID} /bin/bash

5. Inside entry point (default entry folder) run

 jmap -dump:format=b,file=mod-oai-pmh.hprof PID

   a. Name of .hprof file matters. It should be name of service without "-b" postfix. (also you can check how to give a name to this file you can open heapdump.sh script and check one of the last lines it contains proper  name of the file);

   b. To get PID (process ID of the java process) run top command and check java PID.

6. After #5 command will generate .hprof file run 

bash heapdump.sh

7. This command will zip heap dump and sent it to appropriate S3 bucket in heap folder