6 Devops interview questions


Devops is in serious demand these days. At every meetup or tech event I attend, I hear a recruiter or startup founder talking about it. It seems everyone wants to see benefits of talented operations brought to their business.

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That said the skill set is very broad, which explains why there aren’t more devs picking up the batton.

I thought it would be helpful to put together a list of interview questions. There are certainly others, but here’s what I came up with.

1. Explain the gitflow release process

As a devops engineer you should have a good foundation about software delivery. With that you should understand git very well, especially the standard workflow.

Although there are other methods to manage code, one solid & proven method is gitflow. In a nutshell you have two main branches, development & master. Developers checkout a new branch to add a feature, and push it back to development branch. Your stage server can be built automatically off of this branch.

Periodically you will want to release a new version of the software. For this you merge development to master. UAT is then built automatically off of the master branch. When acceptance testing is done, you deploy off of master to production. Hence the saying always ship trunk.

Bonus points if you know that hotfixes are done directly off the master branch & pushed straight out that way.

Related: 8 questions to ask an AWS expert

2. How do you provision resources?

There are a lot of tools in the devops toolbox these days. One that is great at provisioning resources is Terraform. With it you can specify in declarative code everything your application will need to run in the cloud. From IAM users, roles & groups, dynamodb tables, rds instances, VPCs & subnets, security groups, ec2 instances, ebs volumes, S3 buckets and more.

You may also choose to use CloudFormation of course, but in my experience terraform is more polished. What’s more it supports multi-cloud. Want to deploy in GCP or Azure, just port your templates & you’re up and running in no time.

It takes some time to get used to the new workflow of building things in terraform rather than at the AWS cli or dashboard, but once you do you’ll see benefits right away. You gain all the advantages of versioning code we see with other software development. Want to rollback, no problem. Want to do unit tests against your infrastructure? You can do that too!

Related: Does a 4-letter-word divide dev & ops?

3. How do you configure servers?

The four big choices for configuration management these days are Ansible, Salt, Chef & Puppet. For my money Ansible has some nice advantages.

First it doesn’t require an agent. As long as you have SSH access to your box, you can manage it with Ansible. Plus your existing shell scripts are pretty easy to port to playbooks. Ansible also does not require a server to house your playbooks. Simply keep them in your git repository, and checkout to your desktop. Then run ansible-playbook on the yaml file. Voila, server configuration!

Related: How to hire a developer that doesn’t suck

4. What does testing enable?

Unit testing & integration testing are super import parts of continuous integration. As you automate your tests, you formalize how your site & code should behave. That way when you automate the deployment, you can also automate the test process. Let the software do the drudgework of making sure a new feature hasn’t broken anything on the site.

As you automate more tests, you accelerate the software development process, because you’re doing less and less manually. That means being more agile, and makes the business more nimble.

Related: Is AWS too complex for small dev teams?

5. Explain a use case for Docker

Docker a low overhead way to run virtual machines on your local box or in the cloud. Although they’re not strictly distinct machines, nor do they need to boot an OS, they give you many of those benefits.

Docker can encapsulate legacy applications, allowing you to deploy them to servers that might not otherwise be easy to setup with older packages & software versions.

Docker can be used to build test boxes, during your deploy process to facilitate continuous integration testing.

Docker can be used to provision boxes in the cloud, and with swarm you can orchestrate clusters too. Pretty cool!

Related: Will Microservices just die already?

6. How is communicating relevant to Devops

Since devops brings a new process of continuous delivery to the organization, it involves some risk. Actually doing things the old way involves more risk in the long term, because things can and will break. With automation, you can recovery quicker from failure.

But this new world, requires a leap of faith. It’s not right for every organization or in every case, and you’ll likely strike a balance from what the devops holy book says, and what your org can tolerate. However inevitably communication becomes very important as you advocate for new ways of doing things.

Related: How do I migrate my skills to the cloud?

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Marching towards continuous deployment

cute code pipeline

If you’re like a lot of small dev teams & startups, you’ve dreamed of jumping on the continuous deployment train, but still aren’t quite there.

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You’ve got your code in some sort of repository. Now what? As it turns out the concepts aren’t terribly complicated. The hardest part is figuring out the process that works for your team.

1. Make a single script for deployment

Can you build easily? You want to take steps to simplify the build process & work towards everything being done from a single script. This might be an ant or maven script. It might be rake if you’re using ruby. Or it might be a makefile. Either way it organizes dependencies, checks your system & compiles things if necessary.

Also: Do startups need techops?

2. Do nightly builds

If you’re currently doing manual builds, work towards doing them nightly. Once you have that under your belt you can actually schedule these to happen automatically every night. But you’re not there yet. You want to work to improve the build process first. Work on the performance of this process. Quality is also important. Is the build quality poor?

Related: Is there a devops talent gap?

3. Is your build process slow?

If it takes a long time to do the build, it takes a long time to get to the point where you can smoke test. You want to shorten this time, so you can iterate faster. Look at ways to improve the overall performance of the whole chain. What’s it getting stuck on?

Read: 3 things devops can learn from aviation

4. Is your build quality poor?

Your tests are going to verify application functionality, do security checks, performance or even compliance checks. If these are often failing, you need dig in to find the source of your trouble. Tests aren’t specific enough? Or are you passing your tests, but finding a lot of bugs in QA?

It may take your team some time to get better at building the right tests, and reducing the bugs that show up in QA. But this will be crucial to increasing confidence level, where you’ll be ready to automate the whole pipeline. As you become more confident in your tests, then you’ll be confident to automatically deploy to production.

Also: How to deploy on Amazon EC2 with Vagrant

5. Evaluate tools to help

Continuous deployment is a lot about process. Once you’ve gotten a handle on that, you’ll have a much better idea of what you want out of the tools. Amazon’s own CodePipeline is one possible build server you can use. Because it’s a service, it’s one less server you don’t have to manage. And of course Jenkins is a popular option. Even with Jenkins there is a service based offering from CloudBees. You might also take a look at CircleCI, & Travis which are newer service based offerings, which although they don’t have all the plugins & integrations of Jenkins, they’ve learned from bumps in the road, and improved the formula.

We like CircleCI because it’s open source, smaller footprint than Jenkins, integrates with Slack & Hipchat, and has Docker support as well.

Also: 5 Tips for better database change management

Get more. Grab our exclusive monthly Scalable Startups. We share tips and special content. Our latest Why I don’t work with recruiters