启动篇-09 Authorization 授权

buildGenericConfig

cmd/kube-apiserver/app/server.go

func buildGenericConfig(...)(...){
	...
	BuildAuthorizer()
	...
}

BuildAuthorizer

cmd/kube-apiserver/app/server.go

// BuildAuthorizer 构建 Authorizer
func BuildAuthorizer(s *options.ServerRunOptions, EgressSelector *egressselector.EgressSelector, versionedInformers clientgoinformers.SharedInformerFactory) (authorizer.Authorizer, authorizer.RuleResolver, error) {
	authorizationConfig := s.Authorization.ToAuthorizationConfig(versionedInformers)

	if EgressSelector != nil {
		egressDialer, err := EgressSelector.Lookup(egressselector.ControlPlane.AsNetworkContext())
		if err != nil {
			return nil, nil, err
		}
		authorizationConfig.CustomDial = egressDialer
	}

	return authorizationConfig.New()
}

New

pkg/kubeapiserver/authorizer/config.go

// New 返回一个基于 authorizationMode 的多个 authorizer.Authorizer 对象的联合，或者返回一个错误。
func (config Config) New() (authorizer.Authorizer, authorizer.RuleResolver, error) {
	if len(config.AuthorizationModes) == 0 {
		return nil, nil, fmt.Errorf("at least one authorization mode must be passed")
	}

	var (
		authorizers   []authorizer.Authorizer
		ruleResolvers []authorizer.RuleResolver
	)

	// Add SystemPrivilegedGroup as an authorizing group
	superuserAuthorizer := authorizerfactory.NewPrivilegedGroups(user.SystemPrivilegedGroup)
	authorizers = append(authorizers, superuserAuthorizer)

	for _, authorizationMode := range config.AuthorizationModes {
		// Keep cases in sync with constant list in k8s.io/kubernetes/pkg/kubeapiserver/authorizer/modes/modes.go.
		switch authorizationMode {
		// Node 模式
		case modes.ModeNode:
			node.RegisterMetrics()
			graph := node.NewGraph()
			node.AddGraphEventHandlers(
				graph,
				config.VersionedInformerFactory.Core().V1().Nodes(),
				config.VersionedInformerFactory.Core().V1().Pods(),
				config.VersionedInformerFactory.Core().V1().PersistentVolumes(),
				config.VersionedInformerFactory.Storage().V1().VolumeAttachments(),
			)
			nodeAuthorizer := node.NewAuthorizer(graph, nodeidentifier.NewDefaultNodeIdentifier(), bootstrappolicy.NodeRules())
			authorizers = append(authorizers, nodeAuthorizer)
			ruleResolvers = append(ruleResolvers, nodeAuthorizer)

		// AlwaysAllow 模式
		case modes.ModeAlwaysAllow:
			alwaysAllowAuthorizer := authorizerfactory.NewAlwaysAllowAuthorizer()
			authorizers = append(authorizers, alwaysAllowAuthorizer)
			ruleResolvers = append(ruleResolvers, alwaysAllowAuthorizer)
		// AlwaysDeny 模式
		case modes.ModeAlwaysDeny:
			alwaysDenyAuthorizer := authorizerfactory.NewAlwaysDenyAuthorizer()
			authorizers = append(authorizers, alwaysDenyAuthorizer)
			ruleResolvers = append(ruleResolvers, alwaysDenyAuthorizer)
		// ABAC 模式
		case modes.ModeABAC:
			abacAuthorizer, err := abac.NewFromFile(config.PolicyFile)
			if err != nil {
				return nil, nil, err
			}
			authorizers = append(authorizers, abacAuthorizer)
			ruleResolvers = append(ruleResolvers, abacAuthorizer)
		// Webhook 模式
		case modes.ModeWebhook:
			if config.WebhookRetryBackoff == nil {
				return nil, nil, errors.New("retry backoff parameters for authorization webhook has not been specified")
			}
			clientConfig, err := webhookutil.LoadKubeconfig(config.WebhookConfigFile, config.CustomDial)
			if err != nil {
				return nil, nil, err
			}
			webhookAuthorizer, err := webhook.New(clientConfig,
				config.WebhookVersion,
				config.WebhookCacheAuthorizedTTL,
				config.WebhookCacheUnauthorizedTTL,
				*config.WebhookRetryBackoff,
			)
			if err != nil {
				return nil, nil, err
			}
			authorizers = append(authorizers, webhookAuthorizer)
			ruleResolvers = append(ruleResolvers, webhookAuthorizer)
		// RBAC 模式
		case modes.ModeRBAC:
			rbacAuthorizer := rbac.New(
				&rbac.RoleGetter{Lister: config.VersionedInformerFactory.Rbac().V1().Roles().Lister()},
				&rbac.RoleBindingLister{Lister: config.VersionedInformerFactory.Rbac().V1().RoleBindings().Lister()},
				&rbac.ClusterRoleGetter{Lister: config.VersionedInformerFactory.Rbac().V1().ClusterRoles().Lister()},
				&rbac.ClusterRoleBindingLister{Lister: config.VersionedInformerFactory.Rbac().V1().ClusterRoleBindings().Lister()},
			)
			authorizers = append(authorizers, rbacAuthorizer)
			ruleResolvers = append(ruleResolvers, rbacAuthorizer)
		default:
			return nil, nil, fmt.Errorf("unknown authorization mode %s specified", authorizationMode)
		}
	}

	// 合并并返回所有授权器
	return union.New(authorizers...), union.NewRuleResolvers(ruleResolvers...), nil
}