Year: 2017

“MySQL High Availability tools” followup, the missing piece: orchestrator

MySQL

I read with interest MySQL High Availability tools – Comparing MHA, MRM and ClusterControl by SeveralNines. I thought there was a missing piece in the comparison: orchestrator, and that as result the comparion was missing scope and context.

I’d like to add my thoughts on topics addressed in the post. I’m by no means an expert on MHA, MRM or ClusterControl, and will mostly focus on how orchestrator tackles high availability issues raised in the post.

What this is

This is to add insights on the complexity of failovers. Over the duration of three years, I always think I’ve seen it all, and then get hit by yet a new crazy scenario. Doing the right thing automatically is difficult.

In this post, I’m not trying to convince you to use orchestrator (though I’d be happy if you did). To be very clear, I’m not claiming it is better than any other tool. As always, each tool has pros and cons.

This post does not claim other tools are not good. Nor that orchestrator has all the answers. At the end of the day, pick the solution that works best for you. I’m happy to use a solution that reliably solves 99% of the cases as opposed to an unreliable solution that claims to solve 99.99% of the cases.

Quick background

orchestrator is actively maintained by GitHub. It manages automated failovers at GitHub. It manages automated failovers at Booking.com, one of the largest MySQL setups on this planet. It manages automated failovers as part of Vitess. These are some names I’m free to disclose, and browsing the issues shows a few more users running failovers in production. Otherwise, it is used for topology management and visualization in a large number of companies such as Square, Etsy, Sendgrid, Godaddy and more.

Let’s now follow one-by-one the observations on the SeveralNines post. Continue reading » ““MySQL High Availability tools” followup, the missing piece: orchestrator”

MySQL Community Awards 2017: Call for Nominations!

MySQL

The 2017 MySQL Community Awards event will take place, as usual, in Santa Clara, during the Percona Live Data Performance Conference, April 2017.

The MySQL Community Awards is a community based initiative. The idea is to publicly recognize contributors to the MySQL ecosystem. The entire process of discussing, voting and awarding is controlled by an independent group of community members, typically based of past winners or their representatives, as well as known contributors.

It is a self-appointed, self-declared, self-making-up-the-rules-as-it-goes committee. It is also very aware of the importance of the community; a no-nonsense, non-political, adhering to tradition, self criticizing committee.

The Call for Nominations is open. We are seeking the community’s assistance in nominating candidates in the following categories:

MySQL Community Awards: Community Contributor of the year 2017

This is a personal award; a winner would a person who has made contribution to the MySQL ecosystem. This could be via development, advocating, blogging, speaking, supporting, etc. All things go.

MySQL Community Awards: Application of the year 2017

An application, project, product etc. which supports the MySQL ecosystem by either contributing code, complementing its behavior, supporting its use, etc. This could range from a one man open source project to a large scale social service.

MySQL Community Awards: Corporate Contributor of the year 2017

A company who made contribution to the MySQL ecosystem. This might be a corporate which released major open source code; one that advocates for MySQL; one that help out community members by… anything.

For a list of previous winners, please see MySQL Hall of Fame. Continue reading » “MySQL Community Awards 2017: Call for Nominations!”

orchestrator Puppet module now available

MySQL

We have just open sourced and published an orchestrator puppet module. This module is authored by Tom Krouper of GitHub’s database infrastructure team, and is what we use internally at GitHub for deploying orchestrator.

The module manages the orchestrator service, the config file (inherit to override values), etc (pun intended). Check it out!

 

 

Some observations on MySQL to sqlite migration & compatibility

MySQL

I’m experimenting with sqlite as backend database for orchestrator. While orchestrator manages MySQL replication topologies, it also uses MySQL as backend. For some deployments, and I’m looking into such one, having MySQL as backend is a considerable overhead.

This sent me to the route of looking into a self contained orchestrator binary + backend DB. I would have orchestrator spawn up its own backend database instead of connecting to an external one.

Why even relational?

Can’t orchestrator just use a key-value backend?

Maybe it could. But frankly I enjoy the power of relational databases, and the versatility they offer has proven itself multiple times with orchestrator, being able to answer interesting, new, complex questions about one’s topology by crafting SQL queries.

Moreover, orchestrator is already heavily invested in the relational model. At this time, replacing all SQL queries with key-value reads seems to me as a significant investment in time and risk. So I was looking for a relational, SQL accessible embeddable database for orchestrator.

Why sqlite?

I am in particular looking at two options: sqlite (via the go-sqlite3 binding) and TiDB. sqlite does not need much introduction, and I’ll just say it’s embeddable within the golang-built binary. Continue reading » “Some observations on MySQL to sqlite migration & compatibility”