600-parallel-compute

600-parallel-compute

In this example, we distibute a Compute and Network-heavy workload to a Swarm cluster, by again, changing only a few lines of code from os/exec.

The program reads URLs from files.txt and starts containers in parallel to download and compute MD5 checksum of the file using wget -O- [url] | md5sum.

To run this example:

1. Create a swarm cluster, edit its IP address and cert path in main.go.
2. Set your env vars to point to Swarm master:
3. Run:

$ docker pull busybox
$ go run main.go

os/exec vs dexec

Migration from os/exec

Good ol’ 5-lines:

> 	cl, _ := docker.NewClientFromEnv()
> 	d = dexec.Docker{cl}
> 	m, _ := dexec.ByCreatingContainer(docker.CreateContainerOptions{
> 		Config: &docker.Config{Image: "busybox"}})
< 	cmd := exec.Command("sh", "-c", fmt.Sprintf("wget -qO- %s | md5sum", url))
> 	cmd := d.Command(m, "sh", "-c", fmt.Sprintf("wget -qO- %s | md5sum", url))