[Fleet] Warn when trying to unenroll agents with fleet server (#103671)

x-pack/plugins/fleet/public/applications/fleet/sections/agents/agent_details_page/components/actions_menu.tsx

@@ -9,7 +9,7 @@ import React, { memo, useState, useMemo } from 'react';
 import { EuiPortal, EuiContextMenuItem } from '@elastic/eui';
 import { FormattedMessage } from '@kbn/i18n/react';
 
-import type { Agent } from '../../../../types';
+import type { Agent, AgentPolicy, PackagePolicy } from '../../../../types';
 import { useCapabilities, useKibanaVersion } from '../../../../hooks';
 import { ContextMenuActions } from '../../../../components';
 import {
@@ -19,12 +19,14 @@ import {
 } from '../../components';
 import { useAgentRefresh } from '../hooks';
 import { isAgentUpgradeable } from '../../../../services';
+import { FLEET_SERVER_PACKAGE } from '../../../../constants';
 
 export const AgentDetailsActionMenu: React.FunctionComponent<{
   agent: Agent;
+  agentPolicy?: AgentPolicy;
   assignFlyoutOpenByDefault?: boolean;
   onCancelReassign?: () => void;
-}> = memo(({ agent, assignFlyoutOpenByDefault = false, onCancelReassign }) => {
+}> = memo(({ agent, assignFlyoutOpenByDefault = false, onCancelReassign, agentPolicy }) => {
   const hasWriteCapabilites = useCapabilities().write;
   const kibanaVersion = useKibanaVersion();
   const refreshAgent = useAgentRefresh();
@@ -33,6 +35,13 @@ export const AgentDetailsActionMenu: React.FunctionComponent<{
   const [isUpgradeModalOpen, setIsUpgradeModalOpen] = useState(false);
   const isUnenrolling = agent.status === 'unenrolling';
 
+  const hasFleetServer =
+    agentPolicy &&
+    agentPolicy.package_policies.some(
+      (ap: string | PackagePolicy) =>
+        typeof ap !== 'string' && ap.package?.name === FLEET_SERVER_PACKAGE
+    );
+
   const onClose = useMemo(() => {
     if (onCancelReassign) {
       return onCancelReassign;
@@ -58,6 +67,7 @@ export const AgentDetailsActionMenu: React.FunctionComponent<{
               refreshAgent();
             }}
             useForceUnenroll={isUnenrolling}
+            hasFleetServer={hasFleetServer}
           />
         </EuiPortal>
       )}

x-pack/plugins/fleet/public/applications/fleet/sections/agents/agent_details_page/index.tsx

@@ -193,6 +193,7 @@ export const AgentDetailsPage: React.FunctionComponent = () => {
                 isAgentPolicyLoading || agentPolicyData?.item?.is_managed ? undefined : (
                   <AgentDetailsActionMenu
                     agent={agentData.item}
+                    agentPolicy={agentPolicyData?.item}
                     assignFlyoutOpenByDefault={openReassignFlyoutOpenByDefault}
                     onCancelReassign={
                       routeState && routeState.onDoneNavigateTo

x-pack/plugins/fleet/public/applications/fleet/sections/agents/agent_list_page/index.tsx

@@ -22,7 +22,7 @@ import {
 import { i18n } from '@kbn/i18n';
 import { FormattedMessage, FormattedRelative } from '@kbn/i18n/react';
 
-import type { Agent, AgentPolicy, SimplifiedAgentStatus } from '../../../types';
+import type { Agent, AgentPolicy, PackagePolicy, SimplifiedAgentStatus } from '../../../types';
 import {
   usePagination,
   useCapabilities,
@@ -42,7 +42,7 @@ import {
   ContextMenuActions,
 } from '../../../components';
 import { AgentStatusKueryHelper, isAgentUpgradeable } from '../../../services';
-import { AGENT_SAVED_OBJECT_TYPE } from '../../../constants';
+import { AGENT_SAVED_OBJECT_TYPE, FLEET_SERVER_PACKAGE } from '../../../constants';
 import {
   AgentReassignAgentPolicyModal,
   AgentHealth,
@@ -328,6 +328,7 @@ export const AgentListPage: React.FunctionComponent<{}> = () => {
   const agentPoliciesRequest = useGetAgentPolicies({
     page: 1,
     perPage: 1000,
+    full: true,
   });
 
   const agentPolicies = useMemo(
@@ -351,6 +352,23 @@ export const AgentListPage: React.FunctionComponent<{}> = () => {
     return !isHosted;
   };
 
+  const agentToUnenrollHasFleetServer = useMemo(() => {
+    if (!agentToUnenroll || !agentToUnenroll.policy_id) {
+      return false;
+    }
+
+    const agentPolicy = agentPoliciesIndexedById[agentToUnenroll.policy_id];
+
+    if (!agentPolicy) {
+      return false;
+    }
+
+    return agentPolicy.package_policies.some(
+      (ap: string | PackagePolicy) =>
+        typeof ap !== 'string' && ap.package?.name === FLEET_SERVER_PACKAGE
+    );
+  }, [agentToUnenroll, agentPoliciesIndexedById]);
+
   const columns = [
     {
       field: 'local_metadata.host.hostname',
@@ -512,6 +530,7 @@ export const AgentListPage: React.FunctionComponent<{}> = () => {
               fetchData();
             }}
             useForceUnenroll={agentToUnenroll.status === 'unenrolling'}
+            hasFleetServer={agentToUnenrollHasFleetServer}
           />
         </EuiPortal>
       )}

x-pack/plugins/fleet/public/applications/fleet/sections/agents/components/agent_unenroll_modal/index.tsx

@@ -7,7 +7,7 @@
 
 import React, { useState } from 'react';
 import { i18n } from '@kbn/i18n';
-import { EuiConfirmModal, EuiFormFieldset, EuiCheckbox } from '@elastic/eui';
+import { EuiCallOut, EuiConfirmModal, EuiFormFieldset, EuiCheckbox, EuiSpacer } from '@elastic/eui';
 import { FormattedMessage } from '@kbn/i18n/react';
 
 import type { Agent } from '../../../../types';
@@ -22,6 +22,7 @@ interface Props {
   agents: Agent[] | string;
   agentCount: number;
   useForceUnenroll?: boolean;
+  hasFleetServer?: boolean;
 }
 
 export const AgentUnenrollAgentModal: React.FunctionComponent<Props> = ({
@@ -29,6 +30,7 @@ export const AgentUnenrollAgentModal: React.FunctionComponent<Props> = ({
   agents,
   agentCount,
   useForceUnenroll,
+  hasFleetServer = false,
 }) => {
   const { notifications } = useStartServices();
   const [forceUnenroll, setForceUnenroll] = useState<boolean>(useForceUnenroll || false);
@@ -123,6 +125,25 @@ export const AgentUnenrollAgentModal: React.FunctionComponent<Props> = ({
       buttonColor="danger"
     >
       <p>
+        {hasFleetServer && isSingleAgent ? (
+          <>
+            <EuiCallOut
+              title={i18n.translate('xpack.fleet.unenrollAgents.unenrollFleetServerTitle', {
+                defaultMessage: 'This agent is running Fleet Server',
+              })}
+              color="warning"
+              iconType="alert"
+            >
+              <p>
+                <FormattedMessage
+                  id="xpack.fleet.unenrollAgents.unenrollFleetServerDescription"
+                  defaultMessage="Unenrolling this agent will disconnect a Fleet Server and prevent agents from sendind data if no other Fleet Servers exist."
+                />
+              </p>
+            </EuiCallOut>
+            <EuiSpacer />
+          </>
+        ) : null}
         {isSingleAgent ? (
           <FormattedMessage
             id="xpack.fleet.unenrollAgents.deleteSingleDescription"