Setting the time interval of metrics collection in Boatswain

Originally posted on Boatswain Blog.

Boatswain Agent 0.2.12 is released!

Earlier this week we have released a new version of Boatswain (Agent version 0.2.12). Please follow this update guide for different Linux distros. If you are running Boatswain as a container, just use the 0.2.12 image available from Docker Hub.

The new Period attribute

In this release, we have added a new configurable attribute called Period which is the collection time interval of the Server Host and the Docker metrics. Here is the new /etc/boatswain.yml looks like:

# Please register and get the token from https://app.boatswain.io/
token: token_here
# Period is the collection time interval of the host and docker metrics.
# CPU load could be reduced by using longer period.
#   - short   = 10s
#   - default = 30s
#   - long    = 60s
period: default

Prior to agent version 0.2.12, the collection time interval is 10s and there is not way to control it.

Now, as stated in the above config file, there are 3 available options for the new Period attribute and default would be used if this attribute is missing.

The command flag for config file is updated too

When running Boatswain directly through the binary as a foreground process, we could specify the location of the config file using the -f flag (instead of -t prior to agent version 0.2.12).

ykyuen@camus:~# boatswain --help

Usage: boatswain [options]
Options:
  -f string
      boatswain configuration file.
  -v  Show boatswain version and exit.

Server resources consumption VS Period

Setting a longer period means the statistics shown on the Boatswain web portal would have a less sample size but in return, it could reduce system load significantly. Moreover, it could free more data space for monitoring more Docker servers without hitting our BETA 2GB data limit.

Let's run Boatswain to monitor itself with different Period settings. Here are the three runs on a Digital Ocean droplet (1vCPU, 1GB Memory) and it hosts a Drupal 7 application. Each run lasts for 30 mins.

Note: The data size below only includes the metrics which depend on the Period setting.

Period: short (10s)

# CPU consumption:    1.39%
# Memory consumption: 10.06% (104,647,789 Bytes)
# Data size:          8.8MB

Period: default (30s)

# CPU consumption:    0.70%
# Memory consumption: 11.00% (114,425,856 Bytes)
# Data size:          4.3MB

Period: long (60s)

# CPU consumption:    0.57%
# Memory consumption: 6,61% (68,772,546 Bytes)
# Data size:          1.9MB

Result

1. CPU consumption dropped significantly.
   • 🔻 49.64% from 1.39% to 0.70% (Period: 10s ➡️ 30s)
   • 🔻 58.99% from 1.39% to 0.57% (Period: 10s ➡️ 60s)
2. Memory consumption was more or less the same.
   • Although the value dropped a lot (Period: 10s ➡️ 60s), it raised to 11.90% (123,901,542 Bytes) after running 6 hours.
3. Data size dropped significantly.
   • 🔻 51.14% from 8.8MB to 4.3MB (Period: 10s ➡️ 30s)
   • 🔻 78.41% from 8.8MB to 1.9MB (Period: 10s ➡️ 60s)

Other metrics

Boatswain also collects other metrics including

• Container Status
• Container Logs
• Web Analytics

They are independent of the new Period attribute as the logs and web analytics metrics are received in real time while the container status is monitored in a fixed 10s time interval.

What's next?

It has been more than one year since our BETA-I release and Boatswain looks more complete after the recent updates. Probably it's time to move on. 🚢

Stay tuned with us!