Add cpuset_cpus to docker driver.

drivers/docker/config.go

@@ -300,6 +300,7 @@ var (
 		"cap_add":        hclspec.NewAttr("cap_add", "list(string)", false),
 		"cap_drop":       hclspec.NewAttr("cap_drop", "list(string)", false),
 		"command":        hclspec.NewAttr("command", "string", false),
+		"cpuset_cpus":    hclspec.NewAttr("cpuset_cpus", "string", false),
 		"cpu_hard_limit": hclspec.NewAttr("cpu_hard_limit", "bool", false),
 		"cpu_cfs_period": hclspec.NewDefault(
 			hclspec.NewAttr("cpu_cfs_period", "number", false),
@@ -407,6 +408,7 @@ type TaskConfig struct {
 	Command           string             `codec:"command"`
 	CPUCFSPeriod      int64              `codec:"cpu_cfs_period"`
 	CPUHardLimit      bool               `codec:"cpu_hard_limit"`
+	CPUSetCPUs        string             `codec:"cpuset_cpus"`
 	Devices           []DockerDevice     `codec:"devices"`
 	DNSSearchDomains  []string           `codec:"dns_search_domains"`
 	DNSOptions        []string           `codec:"dns_options"`

drivers/docker/driver.go

@@ -823,6 +823,13 @@ func (d *Driver) createContainerConfig(task *drivers.TaskConfig, driverConfig *T
 		Runtime: containerRuntime,
 	}
 
+	// This translates to docker create/run --cpuset-cpus option.
+	// --cpuset-cpus limit the specific CPUs or cores a container can use.
+	if driverConfig.CPUSetCPUs != "" {
+		logger.Debug(fmt.Sprintf("Setting CPUSetCPUs to %s", driverConfig.CPUSetCPUs))
+		hostConfig.CPUSetCPUs = driverConfig.CPUSetCPUs
+	}
+
 	// Calculate CPU Quota
 	// cfs_quota_us is the time per core, so we must
 	// multiply the time by the number of cores available

drivers/docker/driver_test.go

@@ -1381,6 +1381,53 @@ func TestDockerDriver_DNS(t *testing.T) {
 
 }
 
+func TestDockerDriver_CPUSetCPUs(t *testing.T) {
+	if !tu.IsCI() {
+		t.Parallel()
+	}
+	testutil.DockerCompatible(t)
+	if runtime.GOOS == "windows" {
+		t.Skip("Windows does not support CPUSetCPUs.")
+	}
+
+	testCases := []struct {
+		Name       string
+		CPUSetCPUs string
+	}{
+		{
+			Name:       "Single CPU",
+			CPUSetCPUs: "0",
+		},
+		{
+			Name:       "Comma separated list of CPUs",
+			CPUSetCPUs: "0,1,2",
+		},
+		{
+			Name:       "Range of CPUs",
+			CPUSetCPUs: "0-3",
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.Name, func(t *testing.T) {
+			task, cfg, ports := dockerTask(t)
+			defer freeport.Return(ports)
+
+			cfg.CPUSetCPUs = testCase.CPUSetCPUs
+			require.NoError(t, task.EncodeConcreteDriverConfig(cfg))
+
+			client, d, handle, cleanup := dockerSetup(t, task, nil)
+			defer cleanup()
+			require.NoError(t, d.WaitUntilStarted(task.ID, 5*time.Second))
+
+			container, err := client.InspectContainer(handle.containerID)
+			require.NoError(t, err)
+
+			require.Equal(t, cfg.CPUSetCPUs, container.HostConfig.CPUSetCPUs)
+		})
+	}
+}
+
 func TestDockerDriver_MemoryHardLimit(t *testing.T) {
 	if !tu.IsCI() {
 		t.Parallel()

website/pages/docs/drivers/docker.mdx

@@ -77,6 +77,15 @@ The `docker` driver supports the following configuration in the job spec. Only
     command = "my-command"
   }
   ```
+- `cpuset_cpus` - (Optional) CPUs in which to allow execution (0-3, 0,1).
+
+Limit the specific CPUs or cores a container can use. A comma-separated list or hyphen-separated range of CPUs a container can use, if you have more than one CPU. The first CPU is numbered 0. A valid value might be 0-3 (to use the first, second, third, and fourth CPU) or 1,3 (to use the second and fourth CPU).
+
+  ```hcl
+  config {
+    cpuset_cpus = "0-3"
+  }
+  ```
 
 - `dns_search_domains` - (Optional) A list of DNS search domains for the container
   to use.