Leap Second 2015

It Was Like That When I Got Here

L’Observatoire de Paris has decided that there will be a “leap second” on June 30th, 2015.  At 23:59:60 on this date, an additional second will be “inserted” into UTC (Coordinated Universal Time) to take into account the slightly irregular rotation of our planet.

The last “leap second” was on June 30th, 2012, when a bunch of servers running Linux had problems (including, and not limited to, Qantas Airways, reddit and anything running Hadoop).

This year, Google and Amazon both plan to implement a “leap smear” whereby they will add the “leap second” over an extended period on June 30th.

Be aware that a number of AWS services are affected and resolving issues with your EC2 instances is your responsibility.

The “Leap Second” and Oracle
The Oracle database requires no patches and has no problem with the “leap second” changes on the O/S level.

No action is required for…

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Logster is a utility for reading log files and generating metrics to configurable outputs. Graphite, Ganglia, Amazon CloudWatch, Nagios, StatsD and stdout are currently supported. It is ideal for visualizing trends of events that are occurring in your application/system/error logs. For example, you might use logster to graph the number of occurrences of HTTP response code that appears in your web server logs.

Logster maintains a cursor, via a tailer, on each log file that it reads so that each successive execution only inspects new log entries. In other words, a 1 minute crontab entry for logster would allow you to generate near real-time trends in the configured output for anything you want to measure from your logs.

This tool is made up of a framework script, logster, and parsing scripts that are written to accommodate your specific log format. Sample parsers are included in this distribution. The parser scripts essentially read a log file line by line, apply a regular expression to extract useful data from the lines you are interested in, and then aggregate that data into metrics that will be submitted to the configured output. Take a look through the sample parsers, which should give you some idea of how to get started writing your own.

the simplest example of cubism.js

some notes

In this post, I will show the simplest example of cubism.js, hoping that someone interested in cubism.js feels familiar quickly by using this post.

Timeseries chart that cubism.js provides is acuired by the following steps.

1. create context
2. define metrics and metric accessor
3. draw graphs in a way of D3.js
4. add some components (axis, rules, …)

OK. Let’s get started.

First off, let’s create context, which contains state of cubism.js. And create horizon(chart object) from context.

you can change the values from default, such as graph size, steps, serverDelay, etc.. See here for details.

Next, we need to define metric accessor, which tells cubism.js how to get metric values
when a metric name is specified. In this post, metric values are ramdom values whatever the metric name is.
For more details see this part.

And tells cubism.js that this is a metric accessor

And, next? That’s…

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Graphite dashboards

Some wonderful Graphite dashboards










via Installing and Configuring Graphite on CentOS | 4Aiur4Aiur.

Step by Step Guide: ganglia + graphite + cubism.js

some notes

In this post, I’ll build a monitoring infracture with ganglia, graphite, and cubism.js on CentOS 6 in AWS EC2. It is no easy to build such environment, I hope someone (including myself in the future) feels helpful by reading this post.

So let’s get started.

First off. disable iptables and selinux 🙂

Next, setup graphite. Specifying Twisted version and Django version is essential.

Configure graphite. NOTE: If you need an original dashboard, you need to mount them as / (AFAIK there exists no easy solution except but mounting /).

Start carbon-cache and apache.

OK, lets continue to build ganglia. Prepare build-kits and retrieve sourcecode, and build RPMs.

OK, modify gmetad.conf and gmond.conf as follows(unified diff format). NOTE: on EC2, multicast is prohibitted so we need set up to unicast.

Now it’s time to start gmond and gmetad

OK, the last is to put a graphite dashboard alternatives, such as cubism.js…

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