Blockade is a utility for testing network failures and partitions in distributed applications. Blockade uses Docker containers to run application processes and manages the network from the host system to create various failure scenarios.
A common use is to run a distributed application such as a database or cluster and create network partitions, then observe the behavior of the nodes. For example in a leader election system, you could partition the leader away from the other nodes and ensure that the leader steps down and that another node emerges as leader.
Check out the full documentation for details.
- A flexible YAML format to describe the containers in your application
- Support for dependencies between containers, using named links
- A CLI tool for managing and querying the status of your blockade
- Creation of arbitrary partitions between containers
- Giving a container a flaky network connection to others (drop packets)
- Giving a container a slow network connection to others (latency)
- While under partition or network failure control, containers can freely communicate with the host system -- so you can still grab logs and monitor the application.
Blockade was originally developed by the Dell Cloud Manager (formerly Enstratius) team. Blockade was inspired by the excellent Jepsen series.
- docker (>= 1.4.0 due to docker-py)
- iproute2 tools (
Blockade expects a
blockade.yaml file in the current directory which
describes the containers to launch, how they are linked, and various
parameters for the blockade modes. Example:
containers: c1: image: my_docker_image command: /bin/myapp volumes: "/opt/myapp": "/opt/myapp_host" expose:  environment: "IS_MASTER": 1 ports: 81: 80 c2: image: my_docker_image command: /bin/myapp volumes: ["/data"] expose:  links: c1: master c3: image: my_docker_image command: /bin/myapp expose:  links: c1: master network: flaky: 30% slow: 75ms 100ms distribution normal
Blockade stores transient information in a local
This directory will be cleaned up automatically when you run the
blockade destroy command.
Blockade may be used from the command line manually. The commands are also intended to be easy to wrap and automate within tests, etc.
Start the containers and link them together, if necessary.
Destroys all containers and restore networks.
Print the status of the containers and blockade.
blockade flaky n1
blockade flaky n1 n2
Make network flaky to one or more containers.
blockade slow n1
Make network slow to one or more containers.
blockade duplicate n1
Toggle sporadic duplicate packets in the network of one or more containers.
blockade fast n1
Restore network speed and reliability to one or more containers.
blockade partition n1,n2
blockade partition n1,n2 n3,n4
Create one or more network partitions. Each partition is specified as a comma-separated list. Containers may not exist in more than one partition. Containers not specified are grouped into an implicit partition. Each partition command replaces any previous partition or block rules.
Remove all partitions between containers.
Introduce one or many random partitions among the configured nodes.
Blockade is offered under the Apache License 2.0.
Install test dependencies with
pip install blockade[test].
You can run integration tests in a Vagrant VM using the included Vagrantfile.
vagrant up and Docker will be installed in your VM and tests run.
You can rerun them with
vagrant provision, or SSH into the VM and run
them yourself, from
Blockade documentation is built with Sphinx and is found under
$ pip install -r requirements_docs.txt $ cd docs/ $ make html
HTML output will be under
The documentation is also hosted online.