driver: set cpuset when using cgroups v2

README.md

@@ -18,6 +18,7 @@ this plugin to Nomad!
 * Monitor the memory consumption
 * Monitor CPU usage
 * Task config cpu value is used to populate podman CpuShares
+* Task config cores value is used to populate podman Cpuset
 * Container log is forwarded to [Nomad logger](https://www.nomadproject.io/docs/commands/alloc/logs.html)
 * Utilize podmans --init feature
 * Set username or UID used for the specified command within the container (podman --user option).

driver.go

@@ -525,7 +525,7 @@ func (d *Driver) StartTask(cfg *drivers.TaskConfig) (*drivers.TaskHandle, *drive
 	}
 
 	// Set the nomad slice as cgroup parent
-	d.setupCgroup(createOpts)
+	d.setupCgroup(&createOpts)
 
 	// Resources config options
 	createOpts.ContainerResourceConfig.ResourceLimits = &spec.LinuxResources{
@@ -769,7 +769,7 @@ func (d *Driver) StartTask(cfg *drivers.TaskConfig) (*drivers.TaskHandle, *drive
 }
 
 // setupCgroup customizes where the cgroup lives (v2 only)
-func (d *Driver) setupCgroup(opts api.SpecGenerator) {
+func (d *Driver) setupCgroup(opts *api.SpecGenerator) {
 	if d.cgroupV2 {
 		opts.ContainerCgroupConfig.CgroupParent = "nomad.slice"
 	}
@@ -804,6 +804,11 @@ func memoryLimits(r drivers.MemoryResources, reservation string) (hard, soft *in
 }
 
 func setCPUResources(cfg TaskConfig, systemResources *drivers.LinuxResources, taskCPU *spec.LinuxCPU) error {
+	// always assign cpuset
+	taskCPU.Cpus = systemResources.CpusetCpus
+
+	// only set bandwidth if hard limit is enabled
+	// currently only docker and podman drivers provide this ability
 	if !cfg.CPUHardLimit {
 		return nil
 	}

driver_test.go

@@ -2123,6 +2123,28 @@ func createInspectImage(t *testing.T, image, reference string) {
 	must.Eq(t, idRef, idTest)
 }
 
+func Test_setTaskCpuset(t *testing.T) {
+	ci.Parallel(t)
+
+	t.Run("empty", func(t *testing.T) {
+		sysResources := &drivers.LinuxResources{CpusetCpus: ""}
+		taskCPU := new(spec.LinuxCPU)
+		cfg := TaskConfig{}
+		err := setCPUResources(cfg, sysResources, taskCPU)
+		must.NoError(t, err)
+		must.Eq(t, "", taskCPU.Cpus)
+	})
+
+	t.Run("non-empty", func(t *testing.T) {
+		sysResources := &drivers.LinuxResources{CpusetCpus: "2,5-8"}
+		taskCPU := new(spec.LinuxCPU)
+		cfg := TaskConfig{}
+		err := setCPUResources(cfg, sysResources, taskCPU)
+		must.NoError(t, err)
+		must.Eq(t, "2,5-8", taskCPU.Cpus)
+	})
+}
+
 func Test_cpuLimits(t *testing.T) {
 	ci.Parallel(t)