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Pumba: Chaos testing tool for Docker

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Demo

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Usage

You can download Pumba binary for your OS from release page.

$ pumba help

NAME:
   Pumba - Pumba is a resiliency tool that helps applications tolerate random Docker container failures.

USAGE:
   pumba [global options] command [command options] [arguments...]

VERSION:
   0.1.11

COMMANDS:
    run  Pumba starts making chaos: periodically (and/or randomly) executes specified chaos actions on specified containers

GLOBAL OPTIONS:
   --host, -H "unix:///var/run/docker.sock"  daemon socket to connect to [$DOCKER_HOST]
   --tls                                     use TLS; implied by --tlsverify
   --tlsverify                               use TLS and verify the remote [$DOCKER_TLS_VERIFY]
   --tlscacert "/etc/ssl/docker/ca.pem"      trust certs signed only by this CA
   --tlscert "/etc/ssl/docker/cert.pem"      client certificate for TLS authentication
   --tlskey "/etc/ssl/docker/key.pem"        client key for TLS authentication
   --debug                                   enable debug mode with verbose logging
   --json                                    produce log in JSON format: Logstash and Splunk friendly
   --slackhook                               Slack web hook url. Send Pumba log events to Slack
   --slackchannel "#pumba"                   Slack channel for Pumba log events
   --help, -h                                show help
   --version, -v                             print the version
$ pumba run --help

NAME:
   pumba run - Pumba starts making chaos: periodically (and/or randomly) affecting specified containers.

USAGE:
   pumba run [command options] [arguments...]

DESCRIPTION:
   Ask Pumba to run periodically (and randomly) specified chaos_command on selected container(s).

   List of supported chaos_command(s):
     * STOP - stop running container(s)
     * KILL(:SIGNAL) - kill running container(s), optionally sending specified Linux SIGNAL (SIGKILL by default)
     * RM - force remove running container(s)
     * PAUSE:interval(ms/s/m/h postfix) - pause all processes within running container(s) for specified interval
     * DISRUPT(:netem command)(:target ip) - disrupt the outgoing network of a running container with a specific Network Emulation command and/or limiting to traffic outgoing to specific target IP

OPTIONS:
   --chaos, -c [--chaos option --chaos option]	chaos command: `container(s,)/re2:regex|interval(s/m/h postfix)|chaos_command(see above)`
   --random, -r					Random mode: randomly select single matching container to 'kill'

Pumba Chaos Commands

STOP command

STOP command will stop specified running container/s.

KILL command

KILL command will kill specified running container, sending SIGKILL Linux termination signal by default. It's possible to use other Linux termination signal with KILL command. Pass KILL:{SIGNALNAME} (without braces) to Pumba though chaos option, and Pumba will send passed signal to main process running within your Docker container.

RM command

RM command will stop and force remove specified running container/s.

PAUSE

PAUSE command will pause all processes running inside Docker container for specified interval. The command syntax: PAUSE:INTERVAL. Pause interval is just a number with optional postfix: s, m or h.

DISRUPT command - using Pumba to disrupt containers network

DISRUPT command will introduce network disruptions to a container's outgoing traffic (egress) using netem driver, and optionally limiting to traffic outgoing to specific target ip.

For testing your containers under specific network conditions, Pumba is using the linux Network Emulation driver. As described in the above link, these commands affect the outgoing network traffic (egress), so for example, one may disrupt the backend API service or data service and then test the frontend to see the implications. In order to disrupt communication between specific containers, use the DISRUPT option to specifiy target container IP - Pumba will then filter the outgoing traffic and apply the netem effect only to the traffic going to the specific IP.

A few implementaion points are important to understand:

  • Netem commands are executed on containers using 'docker exec'. In order to change network driver settings, the container must have NET_ADMIN capability - this can be granted via the 'docker run' command, via docker-compose.yml or otherwise.
  • Pumba doesn't (currently) store 'chaos state' and therefore is not aware if the container has been already disrupted. As a result, subsequent calls will disrupt it again using the syntax 'tc qdisc add' instead of 'tc qdisc change'. Another result is that even when Pumba is stopped, the disrupted container is still disrtuped. To manually fix the container, use:
   docker exec container_name tc qdisc del dev eth0 root netem
  • Generally, repeating the same disruption to the network of the same container has no effect. In a way, it will be best to use DISRUPT in random mode, combined with KILL so that disrupted containers will be removed from time to time.
  • Using target IP means Pumba will add a priority queue and a filter on eth0, sending outgoing traffic with the specified IP destination to a secondary queue. The netem command is then applied to the secondary queue.

Example:

   pumba run container-name|10m|DISRUPT:delay 100ms:172.0.0.4
   

Pumba will run 'docker exec' every 10 minutes on container 'container-name' to add the netem driver to eth0 with a delay of 100ms on outgoing traffic to 172.0.0.4

Runing inside Docker container

If you choose to use Pumba Docker image on Linux, use the following command:

docker run -d -v /var/run/docker.sock:/var/run/docker.sock gaiaadm/pumba pumba run --chaos "re2:^hp|10s|KILL:SIGTERM"

The above command, once in a 10 seconds, tries to kill (with SIGTERM signal) all containers named hp(something) on same Docker host, where Pumba container is running.

Note: For Windows and OS X you will need to use --host argument, since there is no unix socket /var/run/docker.sock to mount.

Running Pumba on Kubernetes cluster

If you are running Kubernetes >= 1.1.0. You can take advantage of DaemonSets to automatically deploy the Pumba on all your nodes. On 1.1.x you'll need to explicitly enable the DaemonSets extension, see http://kubernetes.io/v1.1/docs/admin/daemons.html#caveats.

You'll then be able to deploy the DaemonSet with the command

$ kubectl create -f pumba_kube.yml

If you are not running Kubernetes >= 1.1.0 or do not want to use DaemonSets, you can also run the Pumba as a regular docker container on each node you want to make chaos (see above)

Running Pumba on CoreOS cluster

If you are running CoreOS cluster. You can use fleetctl command to deploy Pumba service file on every CoreOS cluster node. You'll then be able to deploy the Pumba service with the command

$ fleetctl start pumba_coreos.service

Build instructions

You can build Pumba with or without Go installed on your machine.

Build using local Go environment

In order to build Pumba, you need to have Go 1.6+ setup on your machine.

Here is the approximate list of commands you will need to run:

cd $GOPATH
mkdir github.com/gaia-adm && cd github.com/gaia-adm
git clone [email protected]:gaia-adm/pumba.git
cd pumba
glide install
go build -v

Build using Docker builder image

You do not have to install and configure Go in order to build and test Pumba project. Pubma builder Docker image contains Go 1.6 and all tools required to build and test Pumba.

First of all clone Pumba git repository:

git clone [email protected]:gaia-adm/pumba.git
cd pumba

Now create a Pumba builder Docker image.

docker build -t pumba/builder -f Build.Dockerfile .

Now you can use pumba/builder to build, test (with coverage) and deploy Pumba.

To build a new Pumba binary run the following command:

docker run --rm -v "$PWD":/go/src/github.com/gaia-adm/pumba -w /go/src/github.com/gaia-adm/pumba pumba/builder script/go_build.sh

To build new Pumba binaries for multiple platforms run the following command (using gox tool):

docker run --rm -v "$PWD":/go/src/github.com/gaia-adm/pumba -w /go/src/github.com/gaia-adm/pumba pumba/builder script/gox_build.sh

To run all Pumba tests and generate coverage report run the following command:

docker run --rm -v "$PWD":/go/src/github.com/gaia-adm/pumba -w /go/src/github.com/gaia-adm/pumba pumba/builder script/coverage.sh --html

Used Libraries and Code

I've also borrowed a code from very nice CenturyLinkLabs/watchtower project.

License

Code is under the Apache Licence v2.

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