all-kube: create Tailscale Service for HA kube-apiserver ProxyGroup (#16572)

Adds a new reconciler for ProxyGroups of type kube-apiserver that will
provision a Tailscale Service for each replica to advertise. Adds two
new condition types to the ProxyGroup, TailscaleServiceValid and
TailscaleServiceConfigured, to post updates on the state of that
reconciler in a way that's consistent with the service-pg reconciler.
The created Tailscale Service name is configurable via a new ProxyGroup
field spec.kubeAPISserver.ServiceName, which expects a string of the
form "svc:<dns-label>".

Lots of supporting changes were needed to implement this in a way that's
consistent with other operator workflows, including:

* Pulled containerboot's ensureServicesUnadvertised and certManager into
  kube/ libraries to be shared with k8s-proxy. Use those in k8s-proxy to
  aid Service cert sharing between replicas and graceful Service shutdown.
* For certManager, add an initial wait to the cert loop to wait until
  the domain appears in the devices's netmap to avoid a guaranteed error
  on the first issue attempt when it's quick to start.
* Made several methods in ingress-for-pg.go and svc-for-pg.go into
  functions to share with the new reconciler
* Added a Resource struct to the owner refs stored in Tailscale Service
  annotations to be able to distinguish between Ingress- and ProxyGroup-
  based Services that need cleaning up in the Tailscale API.
* Added a ListVIPServices method to the internal tailscale client to aid
  cleaning up orphaned Services
* Support for reading config from a kube Secret, and partial support for
  config reloading, to prevent us having to force Pod restarts when
  config changes.
* Fixed up the zap logger so it's possible to set debug log level.

Updates #13358

Change-Id: Ia9607441157dd91fb9b6ecbc318eecbef446e116
Signed-off-by: Tom Proctor <tomhjp@users.noreply.github.com>

kube/certs/certs_test.go

@@ -0,0 +1,250 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package certs
+
+import (
+	"context"
+	"log"
+	"testing"
+	"time"
+
+	"tailscale.com/ipn"
+	"tailscale.com/kube/localclient"
+	"tailscale.com/tailcfg"
+	"tailscale.com/types/netmap"
+)
+
+// TestEnsureCertLoops tests that the certManager correctly starts and stops
+// update loops for certs when the serve config changes. It tracks goroutine
+// count and uses that as a validator that the expected number of cert loops are
+// running.
+func TestEnsureCertLoops(t *testing.T) {
+	tests := []struct {
+		name              string
+		initialConfig     *ipn.ServeConfig
+		updatedConfig     *ipn.ServeConfig
+		initialGoroutines int64 // after initial serve config is applied
+		updatedGoroutines int64 // after updated serve config is applied
+		wantErr           bool
+	}{
+		{
+			name:              "empty_serve_config",
+			initialConfig:     &ipn.ServeConfig{},
+			initialGoroutines: 0,
+		},
+		{
+			name:              "nil_serve_config",
+			initialConfig:     nil,
+			initialGoroutines: 0,
+			wantErr:           true,
+		},
+		{
+			name:          "empty_to_one_service",
+			initialConfig: &ipn.ServeConfig{},
+			updatedConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			initialGoroutines: 0,
+			updatedGoroutines: 1,
+		},
+		{
+			name: "single_service",
+			initialConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			initialGoroutines: 1,
+		},
+		{
+			name: "multiple_services",
+			initialConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+					"svc:my-other-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-other-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			initialGoroutines: 2, // one loop per domain across all services
+		},
+		{
+			name: "ignore_non_https_ports",
+			initialConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+							"my-app.tailnetxyz.ts.net:80":  {},
+						},
+					},
+				},
+			},
+			initialGoroutines: 1, // only one loop for the 443 endpoint
+		},
+		{
+			name: "remove_domain",
+			initialConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+					"svc:my-other-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-other-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			updatedConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			initialGoroutines: 2, // initially two loops (one per service)
+			updatedGoroutines: 1, // one loop after removing service2
+		},
+		{
+			name: "add_domain",
+			initialConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			updatedConfig: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:my-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+					"svc:my-other-app": {
+						Web: map[ipn.HostPort]*ipn.WebServerConfig{
+							"my-other-app.tailnetxyz.ts.net:443": {},
+						},
+					},
+				},
+			},
+			initialGoroutines: 1,
+			updatedGoroutines: 2,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			ctx, cancel := context.WithCancel(context.Background())
+			defer cancel()
+
+			notifyChan := make(chan ipn.Notify)
+			go func() {
+				for {
+					notifyChan <- ipn.Notify{
+						NetMap: &netmap.NetworkMap{
+							DNS: tailcfg.DNSConfig{
+								CertDomains: []string{
+									"my-app.tailnetxyz.ts.net",
+									"my-other-app.tailnetxyz.ts.net",
+								},
+							},
+						},
+					}
+				}
+			}()
+			cm := &CertManager{
+				lc: &localclient.FakeLocalClient{
+					FakeIPNBusWatcher: localclient.FakeIPNBusWatcher{
+						NotifyChan: notifyChan,
+					},
+				},
+				logf:      log.Printf,
+				certLoops: make(map[string]context.CancelFunc),
+			}
+
+			allDone := make(chan bool, 1)
+			defer cm.tracker.AddDoneCallback(func() {
+				cm.mu.Lock()
+				defer cm.mu.Unlock()
+				if cm.tracker.RunningGoroutines() > 0 {
+					return
+				}
+				select {
+				case allDone <- true:
+				default:
+				}
+			})()
+
+			err := cm.EnsureCertLoops(ctx, tt.initialConfig)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("ensureCertLoops() error = %v", err)
+			}
+
+			if got := cm.tracker.RunningGoroutines(); got != tt.initialGoroutines {
+				t.Errorf("after initial config: got %d running goroutines, want %d", got, tt.initialGoroutines)
+			}
+
+			if tt.updatedConfig != nil {
+				if err := cm.EnsureCertLoops(ctx, tt.updatedConfig); err != nil {
+					t.Fatalf("ensureCertLoops() error on update = %v", err)
+				}
+
+				// Although starting goroutines and cancelling
+				// the context happens in the main goroutine, it
+				// the actual goroutine exit when a context is
+				// cancelled does not- so wait for a bit for the
+				// running goroutine count to reach the expected
+				// number.
+				deadline := time.After(5 * time.Second)
+				for {
+					if got := cm.tracker.RunningGoroutines(); got == tt.updatedGoroutines {
+						break
+					}
+					select {
+					case <-deadline:
+						t.Fatalf("timed out waiting for goroutine count to reach %d, currently at %d",
+							tt.updatedGoroutines, cm.tracker.RunningGoroutines())
+					case <-time.After(10 * time.Millisecond):
+						continue
+					}
+				}
+			}
+
+			if tt.updatedGoroutines == 0 {
+				return // no goroutines to wait for
+			}
+			// cancel context to make goroutines exit
+			cancel()
+			select {
+			case <-time.After(5 * time.Second):
+				t.Fatal("timed out waiting for goroutine to finish")
+			case <-allDone:
+			}
+		})
+	}
+}