I assume that you've gone trough the first 2 articles and have a finished build artifact (which is a tar file of your built Meteor application) in AWS S3. There should also be a failing deployment stage for Elastic Beanstalk. In this article we are going to focus on preparing this stage to run our Meteor build using Elastic Beanstalk.
Configuring Elastic Beanstalk for Meteor
There are a number of reasons why Elastic Beanstalk is not yet able to run the build. Here's a short summary of the required obstacles to overcome:
- Elastic Beanstalk still uses the repository code and not the build artifact.
- The command used to start the application needs to be configured.
- The environment variables need to be adjusted in the Elastic Beanstalk Console.
- The NodeJS version of the server needs to align with Meteor's NodeJS version
Before we proceed, lets recap our goal. We want to have working Continuous Integration flow for our Meteor application. A push to our repository should eventually result in an updated application in our cloud.
To reach our above goal, we need to consider some extra points:
- We need to work with a loadbalancer and an autoscaling group
- We need to name our environments to always be unique and identifiable
- We need to enable the right settings to allow HTTPS later on
Exploring Elastic Beanstalk
This section does not contain any concrete steps, but instead gives you a gentle introduction into Elastic Beanstalk. It also includes some powerful practices that will help you to prevent some common mistakes and gotchas down the road.
Elastic Beanstalk is an easy to use application service. It handles the deployment, monitoring, scaling and loadbalancing of applications using other AWS services like Cloudwatch. It supports multiple platforms like Python, PHP, .net and Docker. Below is a list of some of the services it uses under the hood. It will give you an idea about what you would normally have to do if you decide to go manual.
- Ec2 instances. It spins up Ec2 virtual servers to run the application. This includes the configuration of EBS Volumes, naming, tagging, and allocating public IP's.
- Ec2 autoscaling and loadbalancing. It helps you set up the scaling and loadbalancing of your application. The Elastic Beanstalk interface allows you to configure on what metrics it needs to scale.
- Cloudwatch. Used for logging and monitoring. The Elastic Beanstalk console allows you to easily set up Cloudwatch triggers that increase or decrease the number of instances based on for example CPU usage or response times.
- S3. Elastic Beanstalk uses S3 buckets to store application code in the form of a tar file. You can upload a tar file using the Elastic Beanstalk console. After the upload it will trigger the environment to download and use the new code.
Naming resources in AWS
Conventions are basically result of agreements. Reinventing the wheel on this might prove to be a bad idea. I would go for standards that exist for ages (software ages, hehe). They work almost all the time and allow you to tailor it a little bit to your own needs.
Elastic Beanstalk works by creating 'applications'. Each application can have multiple environments. How these environments are used is up to you. Over time I've noticed that some approaches work and others don't, so in that sense I'm quite opinionated in how to set up an environment using Elastic Beanstalk. If you have alternatives or better approaches, please share and discuss them on Meteor's forum! I'm not saying that my approach works for each use-case, just that it works for most.
I always name the applications after the customer focused name. In our case the name of the project in CodeStar that we've created in part one. For example, this tutorial's project is called 'tutorial'. The environments in this setup are essentially so called Deployment Environments, meaning that they are part of the application's release cycle. A production ready application typically has 3 deployment environments: Development, Staging and Production. However there are many flavors. Again these 3 are most common. Below a short description of some environment types:
- Local: This environment does not exist in the cloud. It runs only on the developer's machine.
- Development: This runs in the cloud and contains the merged codebase from different developers. You might want to downscale or shutdown this environment during weekends and off hours to save costs.
- Testing (optional): This environment might suit human testers. It allows them to use a test protocol to see if any new features are working as expected. If you don't have dedicated testers or a test protocol, this environment might not be needed.
- Staging: Also known as Pre Production or Acceptance. This is the final step before the application will be run in production. Manual tests are done by testers and stakeholders to double check any requested features and a final go-ahead should be given. This environment contains data that matches production data as closely as possible. This environment is most suited for any demo's to end-users or stakeholders.
- Production: This is where the production / live application runs. This environment should never go down. No tests are allowed to be done here!
Naming and using environments like above will prevent human error, regressions and unstable deployments. It also creates a predictable release cycle towards your stakeholders, because they know where to find new stuff. In Elastic Beanstalk environment names must be unique for your entire cloud! This means that you cannot call them just 'tutorial', 'development' or 'production'. I've created quite a solid convention over time and applied fixes for any gotchas that I've faced along the way. Its simple, but very powerful and works in most cases:
- customer is the name of your customer like in your invoice. Some developers don't have apps per customer. Just use your company's name or your nickname. You can leave out this part if you will never have any customer specific entities on your AWS account.
- application is the name of the application. In this case 'tutorial'
- server-type is the type of the application. I'm using this to identify if
that its a web server, a crawler, Mongo database or whatever. I will provide a
list of examples later on in an article about naming conventions in AWS, but
here's a small list of examples:
- web Servers that run Meteor or any other application facing users
- bastion Servers that act as a bastion host
- mongo Servers that run a mongo database
- api Servers that run an api like a REST API or DDP API
- worker Servers that run a generic worker process supporting the application
- deployment-environment: production, staging, development, testing etc.
An example for our tutorial application would be to have 3 environments named
cloudspider-tutorial-web-pro. This prevents colliding names and also
results in a searchable, predictable, maintainable and scale-able cloud
infrastructure. Another nice benefit is that the generated URL in your
environments will have that name. In my case:
Replacing the default environment
In the previous chapter I've explained why naming is important. However our default Elastic Beanstalk environment has been set up differently. Lets change this to match our final result. To do this, go to the AWS Elastic Beanstalk Console. We'll leave the current environment intact for now and just create our own.
- Create a new application. On the top right corner of the page, there is button for that.
- Name the application using the naming convention. In my case:
cloudspider-tutorial. Optionally describe the application with more words.
- New environment. Click 'Create Web Server'
- Select platform. Preconfigured NodeJS
- Select environment type. Loadbalancing, Autoscaling and click 'Next'
- Select source. Sample application and click 'Next'
- Name your environment according to our conventions: In my case
cloudspider-tutorial-web-dev. Optionally describe it and click 'Next'
- VPC or not? It depends on your own requirements. I usually have 1 VPC per customer. For the sake of this tutorial I'm just clicking 'Next'.
- Instance type 't2.micro' should be fine for now. Especially for small Meteor apps. Ofcourse this is up to you if you expect many users, etc. etc.
- EC2 Keypair. Its the same as the one in Part 1 of this guide when you were setting up the CodeStar project. Its the one that enables you to SSH into your servers. More info on the AWS guide on creating key pairs.
- Email address. Elastic Beanstalk will register an SNS topic to this address. Whenever something happens on the environment, this email will get the alerts.
- Health Check URL. Put a '/' (slash) in there. Its the URI that the loadbalancer will use to check if your application is still running.
- Click next
- Environment Tags. If done right, they will make your DevOps live easier, because it allows you to split invoices, filter and group things in AWS list views like Ec2's instances table. I'm using 5 tags on this screen:
- Customer: Cloudspider
- Application: Tutorial
- Platform: Meteor
- Environment: Development
- Type: Web
- Permissions. Just click "Next'
- Summary. Just double check and then click 'Launch'
Lets just wait until the environment is Green. It should result in a sample NodeJS application being visible when you click the link above the environment.
Connecting the new environment to CodeStar
Our Elastic Beanstalk Environment is running now, but its not connected to our CodeStar project. So lets connect that first by following the below steps:
- Navigate to the CodePipeLine of your project
- Click on the grey 'Edit' button
- There is the third stage called 'Application' with 1 action called 'EBStack'.
- Lets remove that one. Why? Because the name is not descriptive enough. Setting up a new one is very easy and done within 1 minute. Click on the circle with the cross icon within the EBStack action to remove it. Note: there are 2 remove icons. Make sure that you don't remove the Application stage!
- Lets create a new action in the application stage. Click the pencil icon on the top right of the application stage.
- Click on the Action square (with the plus sign)
- Action category: Deploy
- Action name DeployMeteor
- Deployment provider AWS Elastic Beanstalk
- Application name: Select or type the Elastic Beanstalk application that you've created earlier on. Mine is cloudspider-tutorial.
- Environment name: The Elastic Beanstalk environment. Mine is: cloudspider-tutorial-web-dev
- Input Artifact: Select or type the name of the output artifact of the previous stage (Build stage). Which in our case is built-meteor-app.
- Click the blue 'Update' button.
- Click the grey 'Save pipeline changes'. (Above the Pipeline project page)
Lets just click the blue 'Release change' button. We still expect this to fail, because we need to configure some additional things in our Elastic Beanstalk environment to make it work with Meteor's bundle. However, this allows us to check if the pipeline is working as expected. The expected outcome is a red environment and a red failed MeteorDeploy stage in our pipeline.
Errors are scary, but awesome, because in this case it will tell us what went 'wrong'. The expectation is that Elastic Beanstalk will tell us that it tried to start our bundle, but that it wasn't able to. What we don't want is any other error about for example permissions. To see the error click on the 'Details' link on the failing MeteorDeploy stage. Like below image:
The error looks like below image:
We now know that the pipeline is working. Lets verify if it has used the correct build artifact. Navigate to the Elastic Beanstalk service index page. Click on your application name. It should show 3 links. Click on 'Application versions'. Now check if there is a version with a description that is prepended by built-meteor-app-. Click on the link on the Source column to download the artifact. Check if the contents represent the built meteor bundle.
This step might feel like overkill, but its best to understand if and where it goes wrong. At least you now know where to find what Elastic Beanstalk tried to run and you now know for sure that up until this step everything is working as expected.
In part 4 of this guide I will explain how to tweak the Elastic Beanstalk environment to run this Meteor bundle.