Building a NodeJS App with MongoDB Atlas and AWS Elastic Container Service - Part 2

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Jay Gordon
November 09, 2017
Category: AWS re:Invent 2017
It's that time of year again! This post is part of our Road to AWS re:Invent 2017 blog series. In the weeks leading up to AWS re:Invent in Las Vegas this November, we'll be posting about a number of topics related to running MongoDB in the public cloud. See all posts here.

In my last post, we started preparing an application built on Node.js and MongoDB Atlas for simple CRUD operations. We've completed the initial configuration of the code and are now ready to launch this into production.

As mentioned in part one, I want to minimize the long-term maintenance of this app's hosting environment. Much like we used MongoDB Atlas to offload many of the operational responsibilities for our database, we can make use of Amazon EC2 Container Service to deploy our Docker apps on AWS. By reducing the amount of patching, systems maintenance, and long term security concerns for both our database and our application front-end, we’re able to dedicate more time to application development.

Ready Docker and coldbrew-cli for deploy

Docker and coldbrew-cli have simple configuration files we'll review and write in our repo's root directory.

Docker

Let's take a look at the Dockerfile:

This file will tell Docker to follow the instructions to use the "boron" LTS version of Node.js, meaning we won't need to install it manually to work with our application. After establishing the appropriate version of Node.js to use, we'll then make a working directory on the container telling it where the app will live. The app will be copied into the working directory, "/usr/src/app", and finally be started using the npm start command stated in our package.json file.

Place the contents of the Dockerfile in the root of the code repository and save it.

echo "FROM node:boron
>
> RUN mkdir -p /usr/src/app
>WORKDIR /usr/src/app
>
>COPY . /usr/src/app
>
>EXPOSE 3000
>
>CMD ["npm", "start"]" > Dockerfile

Next, we'll start working with coldbrew-cli. Much like Docker, we’ll create a plain text config file that will contain basic instructions on how to configure our infrastructure for our app.

coldbrew-cli

Let’s create a file called coldbrew.conf in the root of our repository directory and then store the following contents in it:

touch coldbrew.conf

For a full breakdown of all the terms in this file, have a look at the coldbrew-cli docs. I have provided a simple configuration file that will set up our elastic load balancing (ELB) with a compute instance for our container and 500 MB of available memory per app. We can even configure a simple health check for our ELB to ensure our instances are online.

We can now create our environment with coldbrew-cli. For the purposes of this walkthrough, let’s say we want to deploy our ECS cluster in the us-east-2 region and that we don’t need to access our nodes via SSH; we can launch using the following command:

$ coldbrew --aws-region="us-east-2" cluster-create mern-demo --disable-keypair

Once executing this, we'll be shown a list of resources that will be created:

Determining AWS resources to create...
  ECS Cluster: coldbrew-mern-demo
  IAM Role for ECS Services: coldbrew-mern-demo-ecs-service-role
  EC2 Launch Configuration for ECS Container Instances: coldbrew-mern-demo-lc
  EC2 Auto Scaling Group for ECS Container Instances: coldbrew-mern-demo-asg
  IAM Instance Profile for ECS Container Instances: coldbrew-mern-demo-instance-profile
  EC2 Security Group for ECS Container Instances: coldbrew-mern-demo-instance-sg

Do you want to create these resources? [y/N]:

Answer “Yes”, and your resources will start building in the background.

[+] Creating IAM Instance Profile [coldbrew-mern-demo-instance-profile]...
[+] Creating EC2 Security Group [coldbrew-mern-demo-instance-sg]...
[*] Adding inbound rule [tcp:22:0.0.0.0/0] to EC2 Security Group [coldbrew-mern-demo-instance-sg]...
[+] Creating EC2 Launch Configuration [coldbrew-mern-demo-lc]... (this may take long)
[+] Creating EC2 Auto Scaling Group [coldbrew-mern-demo-asg]... (this may take long)
[+] Creating ECS Cluster [coldbrew-mern-demo]...
[+] Creating IAM Role [coldbrew-mern-demo-ecs-service-role]...

We can query the status with the following command:

$ coldbrew --aws-region="us-east-2" cluster-status mern-demo

Here is the command output similar to what we would get:

Cluster
  Name: mern-demo
AWS
  Region: us-east-2
  VPC: vpc-7935db10
  Subnets: subnet-70f0df3a subnet-58e01531 subnet-49d4db31
ECS
  ECS Cluster: coldbrew-mern-demo
  IAM Role for ECS Services: coldbrew-mern-demo-ecs-service-role
  ECS Services: 0
  ECS Tasks (running/pending): 0/0
  ECS Container Instances: 1
Auto Scaling
  EC2 Launch Configuration: coldbrew-mern-demo-lc
    IAM Instance Profile: coldbrew-mern-demo-instance-profile
    Instance Type: t2.micro
    Image ID: ami-bd3e64d8
    Key Pair:
    Security Groups: coldbrew-mern-demo-instance-sg
  EC2 Auto Scaling Group: coldbrew-mern-demo-asg
    Instances (current/desired/min/max): 1/1/0/1
ECS Container Instance
  ID: a56d40d1-7095-45a0-af81-5f309bbbd728
  Status: ACTIVE
  Tasks (running/pending): 0/0
  CPU (remaining/registered): 1.00/1.00
  Memory (remaining/registered): 995M/995M,
  EC2 Instance ID: i-03fdc038f3d1c71c8
    Private IP: 172.31.44.140
    Public IP: 18.221.72.130

Wow, that's a lot of saved work. Everything from our VPC all the way to the ELB was created for us. See the public IP for our compute instance? Let's make sure it's whitelisted in our Atlas cluster so our data can be saved.

If you were to replace the M0 free cluster with one of Atlas’s dedicated clusters, you'd have access to our VPC peering module for AWS, giving you the ability to whitelist the entire range of host servers via a security group entry in the whitelist.

Now it's time to build our Docker image with coldbrew-cli and deploy our app.

First a Docker image is created and saved:

$ coldbrew --aws-region="us-east-2" deploy


[*] Checking cluster availability [mern-demo]...
[+] Creating ECR Repository [coldbrew/mern-demo]...
[*] Building Docker image [722245653955.dkr.ecr.us-east-2.amazonaws.com/coldbrew/mern-demo:latest]... (this may take long)

> docker build -t 722245653955.dkr.ecr.us-east-2.amazonaws.com/coldbrew/mern-demo:latest -f /Users/jaygordon/work/mern-crud/Dockerfile /Users/jaygordon/work/mern-crud

Then the image is pushed to the appropriate nodes in the cluster:

[*] Pushing Docker image [722245653955.dkr.ecr.us-east-2.amazonaws.com/coldbrew/mern-demo:latest]... (this may take long)

> docker push 722245653955.dkr.ecr.us-east-2.amazonaws.com/coldbrew/mern-demo:latest
The push refers to a repository [722245653955.dkr.ecr.us-east-2.amazonaws.com/coldbrew/mern-demo]
a791685d46cb: Pushed
e71eccb6eee4: Pushed
b7f1d9d858aa: Pushed
246ae56dbdbd: Pushed
e271ac6d0c18: Pushed
682e7cee9d37: Pushed
d359ab38b013: Pushed
latest: digest: sha256:c58153d1fe62dacb1644966ffe4acca6b76cb383aee1f76e0efd97ceaa1a306e size: 2425

[*] Updating ECS Task Definition [mern-demo]...
[+] Creating ELB Target Group [mern-demo-elb-tg]...
[+] Creating EC2 Security Group [mern-demo-elb-sg]...
[*] Adding inbound rule [tcp:80:0.0.0.0/0] to EC2 Security Group [mern-demo-elb-sg]...
[*] Adding inbound rule [tcp:0:sg-f8ab7190] to EC2 Security Group [coldbrew-mern-demo-instance-sg]...
[+] Creating ELB Load Balancer [mern-demo-elb]...
[+] Adding listener (HTTP) for ELB Load Balancer [mern-demo-elb]...
[+] Creating ECS Service [mern-demo]...

Application deployment completed.

Our app is now deployed. Let's get the ELB and verify:

coldbrew --aws-region="us-east-2" status |egrep elb

ELB Target Group: mern-demo-elb-tg
  ELB Load Balancer: mern-demo-elb
    Endpoint: http://mern-demo-elb-2131866240.us-east-2.elb.amazonaws.com:80

The ELB now provides us with an http endpoint to access our app. There's no need to use nginx or any other http server to reverse proxy the Node.js port. The coldbrew-cli deploy process will set up your port forwarding based on the information in the coldbrew.conf file. The cluster creation and deployment takes about five minutes. To test that we're online and running, simply go to the URL provided by coldbrew and add a record to our app (first load may take a minute):

Congratulations, we now have all the tools to build and configure our own ECS cluster using MongoDB Atlas! Destroying the app is pretty simple as well — just run these two commands to terminate all the resources associated with ECS.

$ coldbrew --aws-region="us-east-2" delete
Determining AWS resources that need to be deleted...
  ECS Service: mern-demo
  ECR Repository: coldbrew/mern-demo
  ELB Target Group: mern-demo-elb-tg
  ELB Load Balancer: mern-demo-elb
  EC2 Security Group for ELB Load Balancer: mern-demo-elb-sg
> Do you want to delete these resources? [y/N]: y

After we answer “yes”, the created resources will begin terminating:

[*] Updating ECS Service to stop all tasks [mern-demo]...
[-] Deleting ELB Load Balancer [mern-demo-elb]...
[-] Deleting ELB Target Group [mern-demo-elb-tg]... (this may take long)
[-] Removing inbound rule [tcp:0:sg-f8ab7190] from EC2 Security Group [coldbrew-mern-demo-instance-sg]...
[-] Deleting EC2 Security Group for ELB Load Balancer [mern-demo-elb-sg]... (this may take long)
[-] Deleting ECR Repository [coldbrew/mern-demo]...
[-] Deleting (and draining) ECS Service [mern-demo]... (this may take long)

And now delete the remaining cluster elements:

$ coldbrew --aws-region="us-east-2" cluster-delete mern-demo

Determining AWS resources that need to be deleted...
  ECS Cluster: coldbrew-mern-demo
  IAM Role for ECS Services: coldbrew-mern-demo-ecs-service-role
  EC2 Launch Configuration for ECS Container Instances: coldbrew-mern-demo-lc
  EC2 Auto Scaling Group for ECS Container Instances: coldbrew-mern-demo-asg
  IAM Instance Profile for ECS Container Instances: coldbrew-mern-demo-instance-profile
  EC2 Security Group for ECS Container Instances: coldbrew-mern-demo-instance-sg

> Do you want to delete these resources? [y/N]: y

Answer “yes” and we'll see the remaining compute cluster elements terminated:

[*] Terminating instances in EC2 Auto Scaling Group [coldbrew-mern-demo-asg]... (this may take long)
[-] Deleting EC2 Auto Scaling Group [coldbrew-mern-demo-asg]... (this may take long)
[-] Deleting EC2 Launch Configuration [coldbrew-mern-demo-lc]... 
[-] Deleting IAM Instance Profile [coldbrew-mern-demo-instance-profile]... 
[-] Deleting EC2 Security Group [coldbrew-mern-demo-instance-sg]... 
[-] Deleting ECS Cluster [coldbrew-mern-demo]... 
[-] Deleting IAM Role [coldbrew-mern-demo-ecs-service-role]... 

What's next?

Try this process out with your own application or even with a dedicated MongoDB Atlas cluster to enable VPC peering. You can get a full tutorial on how to configure VPC Peering in MongoDB Atlas by viewing the "Peering your MongoDB Atlas Cluster to AWS" video. You'll be able to use a completely service-based deployment of your application that requires no operating systems to be managed, no kernels to update, and less overall manual work.

If you'd like to sign up for a free MongoDB Atlas cluster, check out our signup page here!

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