Fleet agent policy host name format field

CHANGELOG.md

@@ -40,6 +40,7 @@ alias = [
 
 ### Changes
 
+- Add `host_name_format` to `elasticstack_fleet_agent_policy` to configure host name format (hostname or FQDN) ([#1312](https://github.com/elastic/terraform-provider-elasticstack/pull/1312))
 - Create `elasticstack_kibana_prebuilt_rule` resource ([#1296](https://github.com/elastic/terraform-provider-elasticstack/pull/1296))
 - Add `required_versions` to `elasticstack_fleet_agent_policy` ([#1436](https://github.com/elastic/terraform-provider-elasticstack/pull/1436))
 - Migrate `elasticstack_elasticsearch_security_role` resource to Terraform Plugin Framework ([#1330](https://github.com/elastic/terraform-provider-elasticstack/pull/1330))

Makefile

@@ -28,6 +28,8 @@ KIBANA_API_KEY_NAME ?= kibana-api-key
 FLEET_NAME ?= terraform-elasticstack-fleet
 FLEET_ENDPOINT ?= https://$(FLEET_NAME):8220
 
+RERUN_FAILS ?= 3
+
 export GOBIN = $(shell pwd)/bin
 
 
@@ -53,7 +55,7 @@ testacc-vs-docker:
 
 .PHONY: testacc
 testacc: ## Run acceptance tests
-	TF_ACC=1 go tool gotestsum --format testname --rerun-fails=3 --packages="-v ./..." -- -count $(ACCTEST_COUNT) -parallel $(ACCTEST_PARALLELISM) $(TESTARGS) -timeout $(ACCTEST_TIMEOUT)
+	TF_ACC=1 go tool gotestsum --format testname --rerun-fails=$(RERUN_FAILS) --packages="-v ./..." -- -count $(ACCTEST_COUNT) -parallel $(ACCTEST_PARALLELISM) $(TESTARGS) -timeout $(ACCTEST_TIMEOUT)
 
 .PHONY: test
 test: ## Run unit tests

docs/resources/fleet_agent_policy.md

@@ -18,13 +18,14 @@ provider "elasticstack" {
 }
 
 resource "elasticstack_fleet_agent_policy" "test_policy" {
-  name            = "Test Policy"
-  namespace       = "default"
-  description     = "Test Agent Policy"
-  sys_monitoring  = true
-  monitor_logs    = true
-  monitor_metrics = true
-  space_ids       = ["default"]
+  name             = "Test Policy"
+  namespace        = "default"
+  description      = "Test Agent Policy"
+  sys_monitoring   = true
+  monitor_logs     = true
+  monitor_metrics  = true
+  space_ids        = ["default"]
+  host_name_format = "hostname" # or "fqdn" for fully qualified domain names
 
   global_data_tags = {
     first_tag = {
@@ -52,6 +53,7 @@ resource "elasticstack_fleet_agent_policy" "test_policy" {
 - `download_source_id` (String) The identifier for the Elastic Agent binary download server.
 - `fleet_server_host_id` (String) The identifier for the Fleet server host.
 - `global_data_tags` (Attributes Map) User-defined data tags to apply to all inputs. Values can be strings (string_value) or numbers (number_value) but not both. Example -- key1 = {string_value = value1}, key2 = {number_value = 42} (see [below for nested schema](#nestedatt--global_data_tags))
+- `host_name_format` (String) Determines the format of the host.name field in events. Can be 'hostname' (short hostname, e.g., 'myhost') or 'fqdn' (fully qualified domain name, e.g., 'myhost.example.com'). Defaults to 'hostname'.
 - `inactivity_timeout` (String) The inactivity timeout for the agent policy. If an agent does not report within this time period, it will be considered inactive. Supports duration strings (e.g., '30s', '2m', '1h').
 - `monitor_logs` (Boolean) Enable collection of agent logs.
 - `monitor_metrics` (Boolean) Enable collection of agent metrics.

examples/resources/elasticstack_fleet_agent_policy/resource.tf

@@ -3,13 +3,14 @@ provider "elasticstack" {
 }
 
 resource "elasticstack_fleet_agent_policy" "test_policy" {
-  name            = "Test Policy"
-  namespace       = "default"
-  description     = "Test Agent Policy"
-  sys_monitoring  = true
-  monitor_logs    = true
-  monitor_metrics = true
-  space_ids       = ["default"]
+  name             = "Test Policy"
+  namespace        = "default"
+  description      = "Test Agent Policy"
+  sys_monitoring   = true
+  monitor_logs     = true
+  monitor_metrics  = true
+  space_ids        = ["default"]
+  host_name_format = "hostname" # or "fqdn" for fully qualified domain names
 
   global_data_tags = {
     first_tag = {

internal/fleet/agent_policy/acc_test.go

@@ -525,6 +525,62 @@ func checkResourceAgentPolicySkipDestroy(s *terraform.State) error {
 	return nil
 }
 
+func TestAccResourceAgentPolicyWithHostNameFormat(t *testing.T) {
+	policyName := sdkacctest.RandStringFromCharSet(22, sdkacctest.CharSetAlphaNum)
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { acctest.PreCheck(t) },
+		CheckDestroy: checkResourceAgentPolicyDestroy,
+		Steps: []resource.TestStep{
+			{
+				// Step 1: Create with host_name_format = "fqdn"
+				ProtoV6ProviderFactories: acctest.Providers,
+				SkipFunc:                 versionutils.CheckIfVersionIsUnsupported(agent_policy.MinVersionAgentFeatures),
+				ConfigDirectory:          acctest.NamedTestCaseDirectory("create_with_fqdn"),
+				ConfigVariables: config.Variables{
+					"policy_name": config.StringVariable(fmt.Sprintf("Policy %s", policyName)),
+				},
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "name", fmt.Sprintf("Policy %s", policyName)),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "namespace", "default"),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "description", "Test Agent Policy with FQDN host name format"),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "host_name_format", "fqdn"),
+				),
+			},
+			{
+				// Step 2: Remove host_name_format from config - should use default "hostname"
+				ProtoV6ProviderFactories: acctest.Providers,
+				SkipFunc:                 versionutils.CheckIfVersionIsUnsupported(agent_policy.MinVersionAgentFeatures),
+				ConfigDirectory:          acctest.NamedTestCaseDirectory("remove_host_name_format"),
+				ConfigVariables: config.Variables{
+					"policy_name": config.StringVariable(fmt.Sprintf("Policy %s", policyName)),
+				},
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "name", fmt.Sprintf("Policy %s", policyName)),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "namespace", "default"),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "description", "Test Agent Policy without host_name_format"),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "host_name_format", "hostname"),
+				),
+			},
+			{
+				// Step 3: Explicitly set host_name_format = "hostname"
+				ProtoV6ProviderFactories: acctest.Providers,
+				SkipFunc:                 versionutils.CheckIfVersionIsUnsupported(agent_policy.MinVersionAgentFeatures),
+				ConfigDirectory:          acctest.NamedTestCaseDirectory("update_to_hostname"),
+				ConfigVariables: config.Variables{
+					"policy_name": config.StringVariable(fmt.Sprintf("Policy %s", policyName)),
+				},
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "name", fmt.Sprintf("Policy %s", policyName)),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "namespace", "default"),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "description", "Test Agent Policy with hostname format"),
+					resource.TestCheckResourceAttr("elasticstack_fleet_agent_policy.test_policy", "host_name_format", "hostname"),
+				),
+			},
+		},
+	})
+}
+
 func TestAccResourceAgentPolicyWithRequiredVersions(t *testing.T) {
 	policyName := sdkacctest.RandStringFromCharSet(22, sdkacctest.CharSetAlphaNum)
 

internal/fleet/agent_policy/models.go

@@ -17,13 +17,29 @@ import (
 	"github.com/hashicorp/terraform-plugin-framework/types"
 )
 
+const (
+	// HostNameFormatHostname represents the short hostname format (e.g., "myhost")
+	HostNameFormatHostname = "hostname"
+	// HostNameFormatFQDN represents the fully qualified domain name format (e.g., "myhost.example.com")
+	HostNameFormatFQDN = "fqdn"
+	// agentFeatureFQDN is the name of the agent feature that enables FQDN host name format
+	agentFeatureFQDN = "fqdn"
+)
+
+// apiAgentFeature is the type expected by the generated API for agent features
+type apiAgentFeature = struct {
+	Enabled bool   `json:"enabled"`
+	Name    string `json:"name"`
+}
+
 type features struct {
 	SupportsGlobalDataTags      bool
 	SupportsSupportsAgentless   bool
 	SupportsInactivityTimeout   bool
 	SupportsUnenrollmentTimeout bool
 	SupportsSpaceIds            bool
 	SupportsRequiredVersions    bool
+	SupportsAgentFeatures       bool
 }
 
 type globalDataTagsItemModel struct {
@@ -45,6 +61,7 @@ type agentPolicyModel struct {
 	MonitorMetrics      types.Bool           `tfsdk:"monitor_metrics"`
 	SysMonitoring       types.Bool           `tfsdk:"sys_monitoring"`
 	SkipDestroy         types.Bool           `tfsdk:"skip_destroy"`
+	HostNameFormat      types.String         `tfsdk:"host_name_format"`
 	SupportsAgentless   types.Bool           `tfsdk:"supports_agentless"`
 	InactivityTimeout   customtypes.Duration `tfsdk:"inactivity_timeout"`
 	UnenrollmentTimeout customtypes.Duration `tfsdk:"unenrollment_timeout"`
@@ -84,6 +101,20 @@ func (model *agentPolicyModel) populateFromAPI(ctx context.Context, data *kbapi.
 	model.Name = types.StringValue(data.Name)
 	model.Namespace = types.StringValue(data.Namespace)
 	model.SupportsAgentless = types.BoolPointerValue(data.SupportsAgentless)
+
+	// Determine host_name_format from AgentFeatures
+	// If AgentFeatures contains {"enabled": true, "name": "fqdn"}, then host_name_format is "fqdn"
+	// Otherwise, it defaults to "hostname"
+	model.HostNameFormat = types.StringValue(HostNameFormatHostname)
+	if data.AgentFeatures != nil {
+		for _, feature := range *data.AgentFeatures {
+			if feature.Name == agentFeatureFQDN && feature.Enabled {
+				model.HostNameFormat = types.StringValue(HostNameFormatFQDN)
+				break
+			}
+		}
+	}
+
 	if data.InactivityTimeout != nil {
 		// Convert seconds to duration string
 		seconds := int64(*data.InactivityTimeout)
@@ -377,10 +408,30 @@ func (model *agentPolicyModel) toAPICreateModel(ctx context.Context, feat featur
 	}
 	body.RequiredVersions = requiredVersions
 
+	// Handle host_name_format via AgentFeatures
+	if agentFeature := model.convertHostNameFormatToAgentFeature(); agentFeature != nil {
+		if !feat.SupportsAgentFeatures {
+			// Only error if user explicitly requests FQDN on unsupported version
+			// Default "hostname" is fine - just don't send agent_features
+			if agentFeature.Enabled {
+				return kbapi.PostFleetAgentPoliciesJSONRequestBody{}, diag.Diagnostics{
+					diag.NewAttributeErrorDiagnostic(
+						path.Root("host_name_format"),
+						"Unsupported Elasticsearch version",
+						fmt.Sprintf("host_name_format (agent_features) is only supported in Elastic Stack %s and above", MinVersionAgentFeatures),
+					),
+				}
+			}
+			// On unsupported version with default "hostname", don't send agent_features
+		} else {
+			body.AgentFeatures = &[]apiAgentFeature{*agentFeature}
+		}
+	}
+
 	return body, nil
 }
 
-func (model *agentPolicyModel) toAPIUpdateModel(ctx context.Context, feat features) (kbapi.PutFleetAgentPoliciesAgentpolicyidJSONRequestBody, diag.Diagnostics) {
+func (model *agentPolicyModel) toAPIUpdateModel(ctx context.Context, feat features, existingFeatures []apiAgentFeature) (kbapi.PutFleetAgentPoliciesAgentpolicyidJSONRequestBody, diag.Diagnostics) {
 	monitoring := make([]kbapi.PutFleetAgentPoliciesAgentpolicyidJSONBodyMonitoringEnabled, 0, 2)
 	if model.MonitorLogs.ValueBool() {
 		monitoring = append(monitoring, kbapi.PutFleetAgentPoliciesAgentpolicyidJSONBodyMonitoringEnabledLogs)
@@ -481,5 +532,76 @@ func (model *agentPolicyModel) toAPIUpdateModel(ctx context.Context, feat featur
 	}
 	body.RequiredVersions = requiredVersions
 
+	// Handle host_name_format via AgentFeatures, preserving other existing features
+	if agentFeature := model.convertHostNameFormatToAgentFeature(); agentFeature != nil {
+		if !feat.SupportsAgentFeatures {
+			// Only error if user explicitly requests FQDN on unsupported version
+			// Default "hostname" is fine - just don't send agent_features
+			if agentFeature.Enabled {
+				return kbapi.PutFleetAgentPoliciesAgentpolicyidJSONRequestBody{}, diag.Diagnostics{
+					diag.NewAttributeErrorDiagnostic(
+						path.Root("host_name_format"),
+						"Unsupported Elasticsearch version",
+						fmt.Sprintf("host_name_format (agent_features) is only supported in Elastic Stack %s and above", MinVersionAgentFeatures),
+					),
+				}
+			}
+			// On unsupported version with default "hostname", don't send agent_features
+		} else {
+			body.AgentFeatures = mergeAgentFeature(existingFeatures, agentFeature)
+		}
+	} else if feat.SupportsAgentFeatures && len(existingFeatures) > 0 {
+		// Preserve existing features even when host_name_format is not set
+		body.AgentFeatures = &existingFeatures
+	}
+
 	return body, nil
 }
+
+// convertHostNameFormatToAgentFeature converts the host_name_format field to a single AgentFeature.
+// - When host_name_format is "fqdn": returns {"name": "fqdn", "enabled": true}
+// - When host_name_format is "hostname": returns {"name": "fqdn", "enabled": false} to explicitly disable
+// - When not set: returns nil (no change to existing features)
+func (model *agentPolicyModel) convertHostNameFormatToAgentFeature() *apiAgentFeature {
+	// If host_name_format is not set or unknown, don't modify AgentFeatures
+	if model.HostNameFormat.IsNull() || model.HostNameFormat.IsUnknown() {
+		return nil
+	}
+
+	// Explicitly set enabled based on the host_name_format value
+	// We need to send enabled: false when hostname is selected to override any existing fqdn setting
+	return &apiAgentFeature{
+		Enabled: model.HostNameFormat.ValueString() == HostNameFormatFQDN,
+		Name:    agentFeatureFQDN,
+	}
+}
+
+// mergeAgentFeature merges a single feature into existing features, replacing any feature with the same name.
+// If newFeature is nil, returns existing features unchanged (nil if existing is empty).
+func mergeAgentFeature(existing []apiAgentFeature, newFeature *apiAgentFeature) *[]apiAgentFeature {
+	if newFeature == nil {
+		if len(existing) == 0 {
+			return nil
+		}
+		return &existing
+	}
+
+	// Check if the feature already exists and replace it, otherwise append
+	result := make([]apiAgentFeature, 0, len(existing)+1)
+	found := false
+
+	for _, f := range existing {
+		if f.Name == newFeature.Name {
+			result = append(result, *newFeature)
+			found = true
+		} else {
+			result = append(result, f)
+		}
+	}
+
+	if !found {
+		result = append(result, *newFeature)
+	}
+
+	return &result
+}