How to Install and Use Gremlin on Microsoft Azure

Tammy Butow

Principal SRE

Introduction

Follow this guide to install and use Gremlin on Microsoft Azure and perform a Chaos Engineering experiment using a Gremlin CPU Attack.

Prerequisites

Before you begin this tutorial, you'll need the following:

• An Ubuntu 16.04 server
• A Gremlin account (sign up here)
• A Microsoft Azure account
• The apt-transport-https package to be able to install gremlin from our repo via HTTPS.

Step 1 - Installing the Gremlin Daemon and CLI

First, add the Gremlin Debian repository:

1echo "deb https://deb.gremlin.com/ release non-free" | sudo tee /etc/apt/sources.list.d/gremlin.list

Import the repo’s GPG key:

1sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys C81FC2F43A48B25808F9583BDFF170F324D41134 9CDB294B29A5B1E2E00C24C022E8EF3461A50EF6

Then install the Gremlin daemon and CLI:

1sudo apt-get update && sudo apt-get install -y gremlind gremlin

After you have created your Gremlin account (sign up here) you will need to find your Gremlin Daemon credentials. Login to the Gremlin App using your Company name and sign-on credentials. These were emailed to you when you signed up to start using Gremlin.

Navigate to Team Settings and click on your Team. Make a note of your Gremlin Secret and Gremlin Team ID.

Then initialise Gremlin and follow the prompts:

1gremlin init

You are now ready to create attacks using the Gremlin App.

Step 2 - Creating attacks using the Gremlin App

Login to the Gremlin App using your Company name and sign-on credentials. These details were emailed to you when you created your Gremlin account.

Select Create Attack in the Gremlin App.

Example: The Hello World of Chaos Engineering (a CPU attack)

You can use the Gremlin App or the Gremlin API to trigger Gremlin attacks. You can view the available range of Gremlin Attacks in Gremlin Help.

The Hello World of Chaos Engineering is the CPU Resource Attack. To create a CPU Resource Attack select Resource and then CPU in the dropdown menu.

The CPU Resource Attack will consume CPU resources based on the settings you select. The most popular default settings for a CPU Resource Attack are pre-selected, a default attack will utilize 1 core for 60 seconds. Before you can run the Gremlin attack you will need to click either Exact hosts to run the attack on or click the Random attack option.

Click Exact and select a Gremlin Client in the list.

Your attack will begin to run, you will be able to view its progress via Gremlin Attacks in the Gremlin App.

On your server, run top to check the impact of the Gremlin Attack:

1top
2
3top - 06:26:47 up 7 days,  7:00,  1 user,  load average: 0.28, 0.07, 0.02
4Tasks: 105 total,   1 running, 104 sleeping,   0 stopped,   0 zombie
5%Cpu(s): 79.7 us, 20.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
6KiB Mem :  1016120 total,   127140 free,    93956 used,   795024 buff/cache
7KiB Swap:        0 total,        0 free,        0 used.   712192 avail Mem
8
9  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
1023768 gremlin   20   0   13268  11136   3576 S 99.3  1.1   0:14.05 gremlin
1123766 root      20   0   40388   3600   3072 R  0.3  0.4   0:00.03 top
12    1 root      20   0   37760   5760   3940 S  0.0  0.6   0:13.74 systemd
13    2 root      20   0       0      0      0 S  0.0  0.0   0:00.00 kthreadd
14    3 root      20   0       0      0      0 S  0.0  0.0   0:01.28 ksoftirqd/0
15    5 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 kworker/0:0H
16    7 root      20   0       0      0      0 S  0.0  0.0   0:06.14 rcu_sched
17    8 root      20   0       0      0      0 S  0.0  0.0   0:00.00 rcu_bh
18    9 root      rt   0       0      0      0 S  0.0  0.0   0:00.00 migration/0
19   10 root      rt   0       0      0      0 S  0.0  0.0   0:04.09 watchdog/0

When your attack is complete it will move to Completed Attacks.

Step 3 - Halting a CPU resource attack using the Gremlin App

You can stop a Gremlin Attack at anytime using the Gremlin App. Navigate to Gremlin Attacks and click on the Halt button.

Conclusion

You've installed Gremlin on a Microsoft Azure server running Ubuntu 16.04 and validated that Gremlin works by running the Hello World of Chaos Engineering, the CPU Resource attack. You now possess tools that make it possible for you to explore additional Gremlin Attacks including attacks that impact State and Network.

Gremlin's Developer Guide is a great resource and reference for using Gremlin to do Chaos Engineering. You can also explore the Gremlin Blog for more information on how to use Chaos Engineering with your application infrastructure.