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    eb-healthd-middleware

    1.0.1 • Public • Published

    eb-healthd-middleware

    When running Elastic Beanstalk in multi-container Docker mode the very useful enhanced health reporting does not work out of the box. There are several steps to configure it correctly and unfortunately they are not located in one document. Specifically, it requires one's application to log information about requests in a particular format and location.

    This repo will detail those steps and provide Node.js middleware for Restify and Express to aid in logging appropriately.

    Install

    This module will only work with versions of Node 4 and above:

    npm install eb-healthd-middleware --save

    Setup

    The first step is to create an .ebextensions folder that is uploaded in the same zip archive as your Dockerrun.aws.json file. Place the following yaml file (named 01-nginx-healthd.config) in .ebextensions ensuring the placeholder is replaced with the name of the container to be monitored. This informs the health monitoring agent as to where to find the logs on the host and also sets up a Cron job to periodically delete rotated logs.

    files:
        "/etc/cron.hourly/cron.logcleanup.elasticbeanstalk.healthd.nginx.conf":
            mode: "000755"
            owner: root
            group: root
            content: |
                #!/bin/sh 
                find /var/log/containers/<YOURCONTAINERNAME>/healthd -type f | grep -v application.log.`date -u +"%Y-%m-%d-%H"` | xargs rm -f
        "/home/ec2-user/setup-healthd-appstat.sh":
            mode: "000755"
            owner: root
            group: root
            content: |
                #!/bin/sh 
                set -e
                mkdir -p /var/log/containers/<YOURCONTAINERNAME>/healthd
                chmod 777 /var/log/containers/<YOURCONTAINERNAME>/healthd
                if [ -d "/etc/healthd" ]
                then
                    echo "appstat_log_path: /var/log/containers/<YOURCONTAINERNAME>/healthd/application.log" >> /etc/healthd/config.yaml
                    echo "appstat_unit: sec" >> /etc/healthd/config.yaml
                    echo "appstat_timestamp_on: completion" >> /etc/healthd/config.yaml
                    initctl start healthd || initctl restart healthd
                fi
     
    container_commands:
        01-healthd-configure:
            command: /home/ec2-user/setup-healthd-appstat.sh 

    Once the host's logging location has been created we create mount points for the Docker container. The default logging location is usually /var/log/nginx but is configurable. One must edit the Dockerrun.aws.json to do so (note that the awseb-logs source volume is a preconfigured Elastic Beanstalk volume):

    {
      "AWSEBDockerrunVersion": "2",
      "containerDefinitions": [{
        "name": "<YOURCONTAINERNAME>",
        "image": "mydocker/image:latest",
        "essential": "true",
        "memory": 1700,
        "portMappings": [{
          "hostPort": "80",
          "containerPort": "8080"
        }],
        "mountPoints": [
          {
            "sourceVolume": "awseb-logs-<YOURCONTAINERNAME>",
            "containerPath": "<LOGLOCATION>"
          }
        ]
      }]
    }

    Finally, one must log the requests as they come into the server. To do so we assign some simple middleware to log these in a file of the format /my/log/dir/application.log.yyyy-MM-dd-hh. Ensure that the log directory specified has been created in the Dockerfile.

    For example, using Restify:

    const restify = require('restify');
    const ebHealth = require('eb-healthd-middleware');
     
    const server = restify.createServer({
        name: 'myApi'
    });
        
    server.use(ebHealth({directory: '/my/log/dir'}));

    Or with Express:

    const express = require('express');
    const ebHealth = require('eb-healthd-middleware');
     
    const app = express();
     
    // passing an empty options object will result in a default logging 
    // directory of /var/log/nginx/healthd being used
    app.use(ebHealth({}));

    Install

    npm i eb-healthd-middleware

    DownloadsWeekly Downloads

    1

    Version

    1.0.1

    License

    ISC

    Last publish

    Collaborators

    • svozza