bucketbench

README

bucketbench

Bucketbench is a simple framework for running defined sequences of lifecycle container operations against three different container engines today: the full Docker engine, OCI's runc, and containerd.

Given a bucket is a physical type of container, the name is my attempt to get away from calling it "dockerbench," given it runs against other container engines as well. All attempts to come up with a more interesting name failed before initial release. Suggestions welcome!

Background

This project came about via some performance comparison work happening in the OpenWhisk serverless project. Developers in that project had a python script for doing similar comparisons, but agreed we should extend it to a more general framework which could be easily be extended for other lifecycle operation sequences, as the python script was hardcoded to a specific set of operations.

Usage

Using bucketbench to drive container operations against a specific container runtime requires a configuration file written in a specific YAML format.

The current driver implementations each support a small set of lifecycle operations (defined as an interface in driver/driver.go), and any benchmark definition can mix and match any of those operations within reason. (Obviously operations must be ordered in a way supported by container lifecycle--for example, you can't do stop prior to run.)

Specific command usage for the bucketbench program is as follows:

The YAML file provided via the --benchmark flag will determine which
lifecycle container commands to run against which container runtimes, specifying
iterations and number of concurrent threads. Results will be displayed afterwards.

Usage:
  bucketbench run [flags]

Flags:
  -b, --benchmark string   YAML file with benchmark definition
  -h, --help               help for run
  -s, --skip-limit         Skip 'limit' benchmark run
  -t, --trace              Enable per-container tracing during benchmark runs

Global Flags:
      --log-level string   set the logging level (info,warn,err,debug) (default "warn")

A common invocation for running the "basic" example benchmark might look like:

$ sudo ./bucketbench --log-level=debug run -b examples/basic.yaml

Let's look at the input YAML file format and define the components. Here's the basic.yaml example:

name: Basic
image: alpine:latest
command: date
rootfs: /home/estesp/containers/alpine
detached: true
drivers:
  - 
   type: Docker
   threads: 5
   iterations: 15
  - 
   type: Runc
   threads: 5
   iterations: 50
commands:
  - run
  - stop
  - remove

The initial section sets up a name and a few key pieces of information required for each engine to know what to run:

• name: Give the benchmark a name. This will be used in output and logs.
• image: Choose an image reference to be used by the image-based engine runtimes (containerd 1.0 and Docker). This can be any image reference accepted by the docker pull command. bucketbench will handle reconciling this reference to the format used by containerd 1.0 (e.g. alpine -> docker.io/library/alpine:latest)
• command: [Optional] Specify an override for the image's default command that will be used for the image-based engine runtimes.
• rootfs: For the runc and ctr (legacy containerd/0.2.x) drivers, you will need to provide an exploded rootfs and an OCI config.json since neither of those engines support image/registry interactions.
• detached: Run the containers in detached/background mode.

The next two sections of the YAML provide 1) the configuration of which drivers to execute the benchmark against, and 2) which lifecycle commands to run against each engine.

Driver Configuration

Each driver has the following settings:

• type: One of the four implemented drivers: Runc, Docker, Containerd, Ctr
• clientpath: [Optional] Path to the binary for client executable based drivers. In the case of containerd 1.0 and the CRI driver, this will be the unique UNIX socket path of the gRPC server. For client binary-based drivers, the driver will default to the standard binary name found in the current $PATH
• threads: Integer number of concurrent threads to run. The bucketbench method is to execute 1..n runs, where n is the number of threads and each run adds another concurrent thread. Run 1 only has one thread and Run N will have n concurrent threads.
• iterations: Number of containers to create in each thread and execute the listed commands against.

Command List

Finally, the YAML input needs to have a list of container lifecycle commands. The following commands are accepted as input:

• run: (aliases: start) create and start a container.
• pause: pause a running container
• unpause: (aliases: resume) resume a paused container
• stop: (aliases: kill) stop/kill the running container processes
• remove: (aliases: erase,delete) remove/delete a container instance

Note that bucketbench is not handling any formal state validation on the list of commands. It is currently up to the user to provide a valid/sane ordered list of container lifecycle commands. The container runtimes will error out on incorrect command states (e.g. stop before run).

After the benchmark runs are complete, bucketbench currently provides basic output to show the overall rate (iterations of the operations/second) for each of the thread counts:

             Iter/Thd     1 thrd  2 thrds  3 thrds  4 thrds  5 thrds  6 thrds  7 thrds  8 thrds  9 thrds 10 thrds
Limit            1000    1171.24  1957.17  2101.13  2067.83  1827.92  1637.32  1257.57  1582.36  1306.08  1699.56
Basic:Docker       15       1.40     2.21     2.81
Basic:Runc         50       8.38    15.85    23.00

More detailed information is collected during the runs and a future PR to bucketbench will provide the raw performance data in a consumable format for end users.

To run bucketbench against Runc, Containerd, or the legacy Ctr driver you must use sudo because of the requirements that those tools have for root access. This tool does not manage the two daemon-based engines (containerd and dockerd), and will fail if they are not up and running when the benchmark runs begin.

The tool will start a significant number of containers against these daemons, but attempts to fully cleanup after running each iteration.

Development Notes

The bucketbench tool is most likely only valuable on amd64/linux, as containerd and runc are delivered today as binaries for those platforms. It will most likely build for other platforms, and if run against a tool like Docker for Mac, would probably work against the Docker engine, but not against containerd or runc.

All the necessary dependencies are vendored into the bucketbench tree, so building should be as easy as go build -o bucketbench . Using go install github.com/estesp/bucketbench should work as well.

TODOs

• Decide what to do with the -trace flag, which was only useful with a private build of runc which generated Go pprof traces. Possibly submit trace support to upstream runc.