Google gets Slack with software updates

Homebrew code now open source

Maintaining a large number of Linux servers to power its search and Web application services is at the heart of Google's business and, until now, has remained a closely guarded secret.

Speaking at the Australian Unix Users Group (AUUG) 2006 conference in Melbourne last week, corporate systems administrator Michael Still lifted the lid on some of the tools Google uses internally to manage clusters of servers.

Rather than relying on standard Linux operating system packages, Google developed its own software, dubbed "Slack", and released it as an open source project a year ago but Still said this is the first time the search giant has talked about it publicly.

"Slack is a source deployment system and it's the way we install applications on servers," Still said, adding Slack is based around a centralized configuration repository which is then deployed onto selected machines in a "pull" method. Each of the "worker" machines asks for its new configuration regularly or when a manual command is run.

"An application install is called a Slack role, so if you have an LDAP slave, you have an LDAP slave role," Still said. "You can have more than one role per machine although if the roles are going to tread on each other then your installs will have to handle how to deal with that."

With Slack, Google system administrators build changes or patches against the source control system for configuration. These changes are checked into the central repository, and then to the "Slackmaster", which Still says is "nothing special", just an rsync server.

Slack also support sub-roles for specific parts of an application, and both pre- and post-install scripts.

Still said there are alternatives to Slack, the most obvious being operating system packages, but one advantage of Google's system is there is "no intermediate binary compact form" of the Slack role.

"So it's reasonably easy to go poke around with just the bit you need without going and rebuilding an entire RPM," he said.

While there is no concept of rolling back a Slack role, if something is broken "you fix it and redeploy it everywhere".

"If you really regret that a machine is not an LDAP slave for instance, you have a repeatable operating system install [so] rebuild it for whatever it was meant to be," Still said. "We can get a new server up in probably half an hour."

There is also no logging of what Slack roles were deployed when but Still said that will be fixed soon.

Join the PC World newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection
Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Rodney Gedda

Computerworld
Show Comments

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Matthew Stivala

HP OfficeJet 250 Mobile Printer

The HP OfficeJet 250 Mobile Printer is a great device that fits perfectly into my fast paced and mobile lifestyle. My first impression of the printer itself was how incredibly compact and sleek the device was.

Armand Abogado

HP OfficeJet 250 Mobile Printer

Wireless printing from my iPhone was also a handy feature, the whole experience was quick and seamless with no setup requirements - accessed through the default iOS printing menu options.

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?