moby/hack/integration-cli-on-swarm

Integration Testing on Swarm

IT on Swarm allows you to execute integration test in parallel across a Docker Swarm cluster

Architecture

Master service

• Works as a funker caller
• Calls a worker funker (-worker-service) with a chunk of -check.f filter strings (passed as a file via -input flag, typically /mnt/input)

Worker service

• Works as a funker callee
• Executes an equivalent of TESTFLAGS=-check.f TestFoo|TestBar|TestBaz ... make test-integration-cli using the bind-mounted API socket (docker.sock)

Client

• Controls master and workers via docker stack
• No need to have a local daemon

Typically, the master and workers are supposed to be running on a cloud environment, while the client is supposed to be running on a laptop, e.g. Docker for Mac/Windows.

Requirement

• Docker daemon 1.13 or later
• Private registry for distributed execution with multiple nodes

Usage

Step 1: Prepare images

$ make build-integration-cli-on-swarm

Following environment variables are known to work in this step:

• BUILDFLAGS
• DOCKER_INCREMENTAL_BINARY

Step 2: Execute tests

$ ./hack/integration-cli-on-swarm/integration-cli-on-swarm -replicas 40 -push-worker-image YOUR_REGISTRY.EXAMPLE.COM/integration-cli-worker:latest 

Following environment variables are known to work in this step:

• DOCKER_GRAPHDRIVER
• DOCKER_EXPERIMENTAL

Flags

Basic flags:

• -replicas N: the number of worker service replicas. i.e. degree of parallelism.
• -chunks N: the number of chunks. By default, chunks == replicas.
• -push-worker-image REGISTRY/IMAGE:TAG: push the worker image to the registry. Note that if you have only single node and hence you do not need a private registry, you do not need to specify -push-worker-image.

Experimental flags for mitigating makespan nonuniformity:

• -shuffle: Shuffle the test filter strings

Flags for debugging IT on Swarm itself:

• -rand-seed N: the random seed. This flag is useful for deterministic replaying. By default(0), the timestamp is used.
• -filters-file FILE: the file contains -check.f strings. By default, the file is automatically generated.
• -dry-run: skip the actual workload
• keep-executor: do not auto-remove executor containers, which is used for running privileged programs on Swarm