Tag Archives: azure

Top Amazon Lambda questions for hiring a serverless expert

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If you’re looking to fill a job roll that says microservices or find an expert that knows all about serverless computing, you’ll want to have a battery of questions to ask them.

Join 33,000 others and follow Sean Hull on twitter @hullsean.

For technical interviews, I like to focus on concepts & the big picture. Which rules out coding exercises or other puzzles which I think are distracting from the process. I really like what what the guys at 37 Signals say

“Hire for attitude. Train for skill.”

So let’s get started.

1. How do you automate deployment?

Programming lambda functions is much like programming in other areas, with some particular challenges. When you first dive in, you’ll use the Amazon dashboard to upload a zipfile with your code. But as you become more proficient, you’ll want to create a deployment pipeline.

o What features in Amazon facilitate automatic deployments?

AWS Lambda supports environment variables. Use these for credentials & other data you don’t want in your deployment package.

Amazon’s serverless offering, also supports aliases. You can have a dev, stage & production alias. That way you can deploy functions for testing, without interrupting production code. What’s more when you are ready to push to production, the endpoint doesn’t change.

o What frameworks are available for serverless?

Serverless Framework is the most full featured option. It fully supports Amazon Lambda & as of 1.0 provides support for other platforms such as IBM Openwhisk, Google Cloud Functions & Azure functions. There is also something called SAM or Serverless Application Model which extends CloudFormation. With this, you can script changes to API Gateway, Dynamo DB & Cognos authentication stuff.

If you’re using Auth0 instead of Cognito or Firebase instead of Dynamodb, you’ll have to come up with your own way to automate changes there.

Also: Is the difference between dev & ops a four-letter word?

2. What are the pros of serverless?

Why are we moving to a serverless computing model? What are the advantages & benefits of it?

o easier operations means faster time to market
o large application components become managed
o reduced costs, only pay while code is running
o faster deploy means more experimentation, more agile
o no more worry about which servers will this code run on?
o reduced people costs & less infrastructure
o no chef playbooks to manage, no deploy keys or IAM roles

Related: Is automation killing old-school operations?

3. What are the cons of serverless?

There are a lot of fanboys of serverless, because of the promise & hope of this new paradigm. But what about healthy criticism? A little dose of reality can identify a critical & active mind.

o With Lambda you have less vendor control which could mean… more downtime, system limits, sudden cost changes, loss of functionality or features and possible forced API upgrades. Remember that Amazon will choose the needs of the many over your specific application idiosyncracies.

o There’s no dedicated hardware option with serverless. So you have the multi-tenant challenges of security & performance problems of other customers code. You may even bump into problems because of other customers errors!

o Vendor lock-in is a real obvious issue. Changing to Google Cloud Functions or Azure Functions would mean new deployment & monitoring tools, a code rewrite & rearchitect, and new infrastructure too. You would also have to export & import your data. How easy does Amazon make this process?

o You can no longer store application & state data in local server memory. Because each instantiation of a function will effectively be a new “server”. So everything must be stored in the database. This may affect performance.

o Testing is more complicated. With multiple vendors, integration testing becomes more crucial. Also how do you create dev db instance? How do you fully test offline on a laptop?

o You could hit system wide limits. For example a big dev deploy could take out production functions by hitting an AWS account limit. You would thus have DDoS yourself! You can also hit the 5 minute execution time limit. And code will get aborted!

o How do you do zero downtime deployments? Since Amazon currently deploys function-by-function, if you have a group of 10 or 20 that act as a unit, they will get deployed in pieces. So your app would need to be taken offline during that period or it would be executing some from old version & some from new version together. With unpredictable results.

Read: Do managers underestimate operational cost?

4. How does security change?

o In serverless you may use multiple vendors, such as Auth0 for authentication, and perhaps Firebase for your data. With Lambda as your serverless platform you now have three vendors to work with. More vendors means a larger area across which hackers may attack your application.

o With the function as a service application model, you lose the protective wall around your database. It is no longer safely deployed & hidden behind a private subnet. Is this sufficient protection of your key data assets?

Also: Is the difference between dev & ops a four-letter word?

5. How do you troubleshoot & debug microservices?

o Monitoring & debugging is still very limited. This becomes a more complex process in the serverless world. You can log error & warning messages to CloudWatch.

o Currently Lambda doesn’t have any open API for third party tooling. This will probably come with time, but again it’s hard to see & examine a serverless function “server” while it is running.

o For example there is no New Relic for serverless.

o Performance tuning may be a bit of a guessing game in the serverless space right now. Amazon will surely be expanding it’s offering, and this is one area that will need attention.

Also: Is the difference between dev & ops a four-letter word?

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Which tech do startups use most?

MySQL on Amazon Cloud AWS

Leo Polovets of Susa Ventures publishes an excellent blog called Coding VC. There you can find some excellent posts, such as pitches by analogy, and an algorithm for seed round valuations and analyzing product hunt data.

He recently wrote a blog post about a topic near and dear to my heart, Which Technologies do Startups Use. It’s worth a look.

One thing to keep in mind looking over the data, is that these are AngelList startups. So that’s not a cross section of all startups, nor does it cover more mature companies either.

In my experience startups can get it right by starting fresh, evaluating the spectrum of new technologies out there, balancing sheer solution power with a bit of prudence and long term thinking.

I like to ask these questions:

o Which technologies are fast & high performance?
o Which technologies have a big, vibrant & robust community?
o Which technologies can I find plenty of engineers to support?
o Which technologies have low operational overhead?
o Which technologies have low development overhead?

1. Database: MySQL

MySQL holds a slight lead according to the AngelList data. In my experience its not overly complex to setup and there are some experienced DBAs out there. That said database expertise can still be hard to find .

We hear a lot about MongoDB these days, and it is surely growing in popularity. Although it doesn’t support joins and arbitrary slicing and dicing of data, it is a very powerful database engine. If your application needs more straightforward data access, it can bring you amazing speed improvements.

Postgres is a close third. It’s a very sophisticated database engine. Although it may have a smaller community than MySQL, overall it’s a more full featured database. I’d have no reservations recommending it.

Also: Top MySQL DBA Interview questions

2. Hosting: Amazon

Amazon Web Services is obviously the giant in the room. They’re big, they’re cheap, they’re nimble. You have a lot of options for server types, they’ve fixed many of the problems around disk I/O and so forth. Although you may still experience latency around multi-tenant related problems, you’ll benefit from a truly global reach, and huge cost savings from the volume of customers they support.

Heroku is included although they’re a different type of service. In some sense their offering is one part operations team & one part automation. Yes ultimately you are getting hosting & virtualization, but some things are tied down. Amazon RDS provides some parallels here. I wrote Is Amazon RDS hard to manage?. Long term you’re likely going to switch to an AWS, Joyent or Rackspace for real scale.

I was surprised to see Azure on the list at all here, as I rarely see startups build on microsoft technologies. It may work for the desktop & office, but it’s not the right choice for the datacenter.

Read: Are generalists better at scaling the web?

3. Languages: Javascript

Javascript & Node.js are clearly very popular. They are also highly scalable.

In my experience I see a lot of PHP & of course Ruby too. Java although there is a lot out there, can tend to be a bear as a web dev language, and provide some additional complication, weight and overhead.

Related: Is Hunter Walk right about operations & startups?

4. Search: Elastic Search

I like that they broke apart search technology as a separate category. It is a key component of most web applications, and I do see a lot of Elastic Search & Solr.

That said I think this may be a bit skewed. I think by far the number one solution would be NO SPECIFIC SEARCH technology. That’s right, many times devs choose a database centric approach, like FULLTEXT or others that perform painfully bad.

If this is you, consider these search solutions. They will bring you huge performance gains.

Check this: Are SQL Databases Dead?

5. Automation: Chef

As with search above, I’d argue there is a far more prevalent trend, that is #1 to use none of these automation technologies.

Although I do think chef, docker & puppet can bring you real benefits, it’s a matter of having them in the right hands. Do you have an operations team that is comfortable with using them? When they leave in a years time, will your new devops also know the technology you’re using? Can you find a good balance between automation & manual configuration, and document accordingly?

Read: Why are database & operations experts so hard to find?

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