SYS-CON MEDIA Authors: Tom Leyden, Sean Houghton, Glenn Rossman, Ignacio M. Llorente, Xenia von Wedel

Related Topics: Open Source, Java, SOA & WOA, Linux

Open Source: Article

Memory Monitoring and Limiting with LXC

Building a Metrics Infrastructure

Original article can be found here: Memory Monitoring with LXC

Memory Monitoring And Limiting With LXC

For a long time we didn't limit the amount of memory that you can use during your build on Codeship. There was the possibility of a bad build eating up all of our memory.

A few weeks ago that bad build happened, using up so much memory that it decreased performance and eventually killed the test server. Even though we measure the memory usage of the whole test server, we didn't have the data to figure out exactly which build caused the trouble.

Combined maximum and minimum memory usage of Amazon EC2 Instances.

Combined maximum and minimum memory usage of Amazon EC2 Instances.

How to avoid builds eating up all of your memory
We couldn't risk that this problem happened again and be a threat to other builds on that test server. We didn't have enough data about the memory limits at this point so we had to take an educated guess. My first assumption was the most conservative one. Each test server has 60G of memory and we run 22 builds on each instance, so each build can get a maximum of 2,5G memory. As LXC manages memory with cgroups, it is simple to set a memory limit for each container.

Setting lxc.cgroup.memory.limit_in_bytes in container config:

lxc.cgroup.memory.limit_in_bytes = 2560M

This worked, the bad build wasn't a threat anymore.

We got a few support request where people were asking about their builds being stuck. While the 2,5G are enough for 95% of the builds, the other 5% were hitting the limit. We needed to increase the memory limit to ensure that all builds are running fine. After 2 incremental steps The Codeship is sailing smooth with a 10GB memory limit for each build.

Codeship - A hosted Continuous Deployment platform for web applications

Monitoring in the Future
We wanted to have more data to improve the memory limit in the future. We started measuring the maximum memory usage for each build. We export it to Librato Metrics and save it as metadata of the build in our database. This allows to inspect the memory usage easily. We plan to show the memory usage to our users in the future.

LXC tracks the memory usage for each container and exposes that and many other values in the cgroup. Right before we shutdown the build, we read the memory usage from the cgroup. You can read the memory usage from the cgroup on the LXC Host.

/sys/fs/cgroup/memory/lxc/name_of_running_container/memory.max_usage_in_bytes

and send the data to Librato Metrics.

Metriks.timer('build.memory_usage) .update(metrics[:max_memory])

Building a Metrics Infrastructure
It is important to back your actions with data. Data is your best argument. In case you don't have any useful data to solve the problem, it is important that you can easily add more metrics to your infrastructure. Sit back with your Coworkers and think about good metricsfor your product. Sometimes it's not easy to spot them on the first glimpse. We often talk about our metrics.

We discuss new metrics but also talk about removing redundant metrics. It is very exciting to talk about data and what your Coworkers conclude from that data. We are able to add new metrics to our infrastructure in minutes. By building this metrics infrastructure you can handle any new challenges by quickly adding mesurements that help you decide on the next steps. This infrastructure can be the difference between life and death of your service, so make sure you have it in place.

Do you monitor? Which tools and services do you use for it? Let us know in the comments!

Further Information on Linux Containers


Download Efficiency in Development Workflows: A free eBook for Software Developers. This book will save you a lot of time and make you and your development team happy.

Go ahead and try Codeship for Continuous Integration and Continuous Deployment! Set up for your GitHub and BitBucket projects only takes 3 minutes. It's free!

More Stories By Manuel Weiss

I am the cofounder of Codeship – a hosted Continuous Integration and Deployment platform for web applications. On the Codeship blog we love to write about Software Testing, Continuos Integration and Deployment. Also check out our weekly screencast series 'Testing Tuesday'!

Latest Stories
ScriptRock makes GuardRail, a DevOps-ready platform for configuration monitoring. Realizing we were spending way too much time digging up, cataloguing, and tracking machine configurations, we began writing our own scripts and tools to handle what is normally an enormous chore. Then we took the concept a step further, giving it a beautiful interface and making it simple enough for our bosses to understand. We named it GuardRail after its function - to allow businesses to move fast and stay sa...
SYS-CON Media announced today that Sematext launched a popular blog feed on DevOps Journal with over 6,000 story reads over the weekend. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. DevOps Journal brings valuable information to DevOps professionals who are transforming the way enterprise IT is done. Sematext is a globally distributed organization that builds innovative Cloud and On Premises solutions for performance monitoring, alerting an...
In high-production environments where release cycles are measured in hours or minutes — not days or weeks — there's little room for mistakes and no room for confusion. Everyone has to understand what's happening, in real time, and have the means to do whatever is necessary to keep applications up and running optimally. DevOps is a high-stakes world, but done well, it delivers the agility and performance to significantly impact business competitiveness.
"Our premise is Docker is not enough. That's not a bad thing - we actually love Docker. At ActiveState all our products are based on open source technology and Docker is an up-and-coming piece of open source technology," explained Bart Copeland, President & CEO of ActiveState Software, in this SYS-CON.tv interview at DevOps Summit at Cloud Expo®, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The Internet of Things is not new. Historically, smart businesses have used its basic concept of leveraging data to drive better decision making and have capitalized on those insights to realize additional revenue opportunities. So, what has changed to make the Internet of Things one of the hottest topics in tech? In his session at @ThingsExpo, Chris Gray, Director, Embedded and Internet of Things, discussed the underlying factors that are driving the economics of intelligent systems. Discover ...
"BSQUARE is in the business of selling software solutions for smart connected devices. It's obvious that IoT has moved from being a technology to being a fundamental part of business, and in the last 18 months people have said let's figure out how to do it and let's put some focus on it, " explained Dave Wagstaff, VP & Chief Architect, at BSQUARE Corporation, in this SYS-CON.tv interview at @ThingsExpo, held Nov 4-6, 2014, at the Santa Clara Convention Center in Santa Clara, CA.
The major cloud platforms defy a simple, side-by-side analysis. Each of the major IaaS public-cloud platforms offers their own unique strengths and functionality. Options for on-site private cloud are diverse as well, and must be designed and deployed while taking existing legacy architecture and infrastructure into account. Then the reality is that most enterprises are embarking on a hybrid cloud strategy and programs. In this Power Panel at 15th Cloud Expo (http://www.CloudComputingExpo.com...
Leysin American School is an exclusive, private boarding school located in Leysin, Switzerland. Leysin selected an OpenStack-powered, private cloud as a service to manage multiple applications and provide development environments for students across the institution. Seeking to meet rigid data sovereignty and data integrity requirements while offering flexible, on-demand cloud resources to users, Leysin identified OpenStack as the clear choice to round out the school's cloud strategy. Additional...
Verizon Enterprise Solutions is simplifying the cloud-purchasing experience for its clients, with the launch of Verizon Cloud Marketplace, a key foundational component of the company's robust ecosystem of enterprise-class technologies. The online storefront will initially feature pre-built cloud-based services from AppDynamics, Hitachi Data Systems, Juniper Networks, PfSense and Tervela. Available globally to enterprises using Verizon Cloud, Verizon Cloud Marketplace provides a one-stop shop fo...
The move in recent years to cloud computing services and architectures has added significant pace to the application development and deployment environment. When enterprise IT can spin up large computing instances in just minutes, developers can also design and deploy in small time frames that were unimaginable a few years ago. The consequent move toward lean, agile, and fast development leads to the need for the development and operations sides to work very closely together. Thus, DevOps become...
SYS-CON Events announced today that IDenticard will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. IDenticard™ is the security division of Brady Corp (NYSE: BRC), a $1.5 billion manufacturer of identification products. We have small-company values with the strength and stability of a major corporation. IDenticard offers local sales, support and service to our customers across the United States and Canada...
SYS-CON Media announced today that Aruna Ravichandran, VP of Marketing, Application Performance Management and DevOps at CA Technologies, has joined DevOps Journal’s authors. DevOps Journal is focused on this critical enterprise IT topic in the world of cloud computing. DevOps Journal brings valuable information to DevOps professionals who are transforming the way enterprise IT is done. Aruna's inaugural article "Four Essential Cultural Hacks for DevOps Newbies" discusses how to demonstrate the...
SYS-CON Events announced today that Windstream, a leading provider of advanced network and cloud communications, has been named “Silver Sponsor” of SYS-CON's 16th International Cloud Expo®, which will take place on June 9–11, 2015, at the Javits Center in New York, NY. Windstream (Nasdaq: WIN), a FORTUNE 500 and S&P 500 company, is a leading provider of advanced network communications, including cloud computing and managed services, to businesses nationwide. The company also offers broadband, p...
SYS-CON Events announced today that AIC, a leading provider of OEM/ODM server and storage solutions, will exhibit at SYS-CON's 16th International Cloud Expo®, which will take place on June 9-11, 2015, at the Javits Center in New York City, NY. AIC is a leading provider of both standard OTS, off-the-shelf, and OEM/ODM server and storage solutions. With expert in-house design capabilities, validation, manufacturing and production, AIC's broad selection of products are highly flexible and are conf...

ARMONK, N.Y., Nov. 20, 2014 /PRNewswire/ --  IBM (NYSE: IBM) today announced that it is bringing a greater level of control, security and flexibility to cloud-based application development and delivery with a single-tenant version of Bluemix, IBM's