exec "exec0" {
	cmd => "sleep 10s",
	shell => "/bin/bash",
}
exec "exec1" {
	cmd => "sleep 10s",
	shell => "/bin/bash",
}
exec "exec2" {
	cmd => "sleep 10s",
	shell => "/bin/bash",
}

Exec["exec0"] -> Exec["exec1"] -> Exec["exec2"]
