Autopilot: Server Stabilization, State and Dead Server Cleanup (#10856)

* k8s doc: update for 0.9.1 and 0.8.0 releases (#10825)

* k8s doc: update for 0.9.1 and 0.8.0 releases

* Update website/content/docs/platform/k8s/helm/configuration.mdx

Co-authored-by: Theron Voran <tvoran@users.noreply.github.com>

Co-authored-by: Theron Voran <tvoran@users.noreply.github.com>

* Autopilot initial commit

* Move autopilot related backend implementations to its own file

* Abstract promoter creation

* Add nil check for health

* Add server state oss no-ops

* Config ext stub for oss

* Make way for non-voters

* s/health/state

* s/ReadReplica/NonVoter

* Add synopsis and description

* Remove struct tags from AutopilotConfig

* Use var for config storage path

* Handle nin-config when reading

* Enable testing autopilot by using inmem cluster

* First passing test

* Only report the server as known if it is present in raft config

* Autopilot defaults to on for all existing and new clusters

* Add locking to some functions

* Persist initial config

* Clarify the command usage doc

* Add health metric for each node

* Fix audit logging issue

* Don't set DisablePerformanceStandby to true in test

* Use node id label for health metric

* Log updates to autopilot config

* Less aggressively consume config loading failures

* Return a mutable config

* Return early from known servers if raft config is unable to be pulled

* Update metrics name

* Reduce log level for potentially noisy log

* Add knob to disable autopilot

* Don't persist if default config is in use

* Autopilot: Dead server cleanup (#10857)

* Dead server cleanup

* Initialize channel in any case

* Fix a bunch of tests

* Fix panic

* Add follower locking in heartbeat tracker

* Add LastContactFailureThreshold to config

* Add log when marking node as dead

* Update follower state locking in heartbeat tracker

* Avoid follower states being nil

* Pull test to its own file

* Add execution status to state response

* Optionally enable autopilot in some tests

* Updates

* Added API function to fetch autopilot configuration

* Add test for default autopilot configuration

* Configuration tests

* Add State API test

* Update test

* Added TestClusterOptions.PhysicalFactoryConfig

* Update locking

* Adjust locking in heartbeat tracker

* s/last_contact_failure_threshold/left_server_last_contact_threshold

* Add disabling autopilot as a core config option

* Disable autopilot in some tests

* s/left_server_last_contact_threshold/dead_server_last_contact_threshold

* Set the lastheartbeat of followers to now when setting up active node

* Don't use config defaults from CLI command

* Remove config file support

* Remove HCL test as well

* Persist only supplied config; merge supplied config with default to operate

* Use pointer to structs for storing follower information

* Test update

* Retrieve non voter status from configbucket and set it up when a node comes up

* Manage desired suffrage

* Consider bucket being created already

* Move desired suffrage to its own entry

* s/DesiredSuffrageKey/LocalNodeConfigKey

* s/witnessSuffrage/recordSuffrage

* Fix test compilation

* Handle local node config post a snapshot install

* Commit to storage first; then record suffrage in fsm

* No need of local node config being nili case, post snapshot restore

* Reconcile autopilot config when a new leader takes over duty

* Grab fsm lock when recording suffrage

* s/Suffrage/DesiredSuffrage in FollowerState

* Instantiate autopilot only in leader

* Default to old ways in more scenarios

* Make API gracefully handle 404

* Address some feedback

* Make IsDead an atomic.Value

* Simplify follower hearbeat tracking

* Use uber.atomic

* Don't have multiple causes for having autopilot disabled

* Don't remove node from follower states if we fail to remove the dead server

* Autopilot server removals map (#11019)

* Don't remove node from follower states if we fail to remove the dead server

* Use map to track dead server removals

* Use lock and map

* Use delegate lock

* Adjust when to remove entry from map

* Only hold the lock while accessing map

* Fix race

* Don't set default min_quorum

* Fix test

* Ensure follower states is not nil before starting autopilot

* Fix race

Co-authored-by: Jason O'Donnell <2160810+jasonodonnell@users.noreply.github.com>
Co-authored-by: Theron Voran <tvoran@users.noreply.github.com>

command/server/config_test_helpers.go

@@ -895,3 +895,36 @@ func testLoadConfigFileLeaseMetrics(t *testing.T) {
 		t.Fatal(diff)
 	}
 }
+
+func testConfigRaftAutopilot(t *testing.T) {
+	config, err := LoadConfigFile("./test-fixtures/raft_autopilot.hcl")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	autopilotConfig := `[{"cleanup_dead_servers":true,"last_contact_threshold":"500ms","max_trailing_logs":250,"min_quorum":3,"server_stabilization_time":"10s"}]`
+	expected := &Config{
+		SharedConfig: &configutil.SharedConfig{
+			Listeners: []*configutil.Listener{
+				{
+					Type:    "tcp",
+					Address: "127.0.0.1:8200",
+				},
+			},
+			DisableMlock: true,
+		},
+
+		Storage: &Storage{
+			Type: "raft",
+			Config: map[string]string{
+				"path":      "/storage/path/raft",
+				"node_id":   "raft1",
+				"autopilot": autopilotConfig,
+			},
+		},
+	}
+	config.Listeners[0].RawConfig = nil
+	if diff := deep.Equal(config, expected); diff != nil {
+		t.Fatal(diff)
+	}
+}