This is part 2 in our series on how we upgraded our Elasticsearch cluster without downtime and minimal user impact.

As described in Part 1, our requirements were to both provide a smooth transition between two different versions of our system, while still keeping the opportunities for a rollback open.

With that in mind it was obvious from the beginning that we would have to run two Elasticsearch clusters in parallel and then manage a seamless transition between them. This blog post will describe how we solved the indexing consistency and data migration parts of that problem.

Back in 2018, now five years ago, we published a blog post describing our 400+ node Elasticsearch cluster. In that post we brought up an important topic:

So far, we have elected to not upgrade the cluster. We would like to, but so far there have been more urgent tasks. How we actually perform the upgrade is undecided, but it might be that we choose to create another cluster rather than upgrading the current one.

Well, the day to upgrade finally came.

We had another Devopsicon — our internal engineering (un)conference. We record most of these company-internal sessions to ensure we can share the knowledge with those who were unable to attend, and to build a knowledge base over time.

We have decided to go one step further and share some of these sessions publicly. This post describes how this approach has benefitted both us as a company and the professional growth of our engineers.

A growing Engineering org may reach a point where answering questions that used to be simple have become hard. At least that is true for us! Questions such as: “Who owns this?” “Do we have a component that I can reuse?” “Where are the docs for that API?”

This post shares the challenges we want to solve, and the experiences we made while centralizing our internal developer docs in Backstage, an open platform for building developer portals.

János Csorvási and Jeff Campbell were both part of our Foundation team, when we started our DevOps transformation at Meltwater Engineering a couple of years ago. Now they got together on the Scrum Master Toolbox Podcast to share how that transformation looked like from the perspective of the development teams.