не удается выполнить пинг удаленного ipv6 с помощью calico CNI для k8s

#kubernetes #calico

#kubernetes #calico

Вопрос:

Ниже приведен файл манифеста, который я использовал для включения calico CNI для k8s, модули могут обмениваться данными по ipv4, но я не могу выйти за пределы, используя ipv6, k8s версии v1.14 и calico версии v3.11, мне не хватает некоторых настроек,

пересылка включена на хосте с помощью «sysctl -w net.ipv6.conf.all.forwarding=1»

    ---
# Source: calico/templates/calico-config.yaml
# This ConfigMap is used to configure a self-hosted Calico installation.
kind: ConfigMap
apiVersion: v1
metadata:
  name: calico-config
  namespace: kube-system
data:
  # Typha is disabled.
  typha_service_name: "none"
  # Configure the backend to use.
  calico_backend: "vxlan"

  # Configure the MTU to use
  veth_mtu: "1440"

  # The CNI network configuration to install on each node.  The special
  # values in this config will be automatically populated.
  cni_network_config: |-
    {
      "name": "k8s-pod-network",
      "cniVersion": "0.3.1",
      "plugins": [
        {
          "type": "calico",
          "log_level": "info",
          "datastore_type": "kubernetes",
          "nodename": "__KUBERNETES_NODE_NAME__",
          "mtu": __CNI_MTU__,
          "ipam": {
              "type": "calico-ipam",
              "assign_ipv4": "true",
              "assign_ipv6": "true"
          },
          "container_settings": {
             "allow_ip_forwarding": true
          },
          "policy": {
              "type": "k8s"
          },
          "kubernetes": {
              "kubeconfig": "__KUBECONFIG_FILEPATH__"
          }
        },
        {
          "type": "portmap",
          "snat": true,
          "capabilities": {"portMappings": true}
        }
      ]
    }

---
# Source: calico/templates/kdd-crds.yaml
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: felixconfigurations.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: FelixConfiguration
    plural: felixconfigurations
    singular: felixconfiguration
---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: ipamblocks.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: IPAMBlock
    plural: ipamblocks
    singular: ipamblock

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: blockaffinities.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: BlockAffinity
    plural: blockaffinities
    singular: blockaffinity

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: ipamhandles.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: IPAMHandle
    plural: ipamhandles
    singular: ipamhandle

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: ipamconfigs.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: IPAMConfig
    plural: ipamconfigs
    singular: ipamconfig
---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: ippools.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: IPPool
    plural: ippools
    singular: ippool

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: hostendpoints.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: HostEndpoint
    plural: hostendpoints
    singular: hostendpoint

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: clusterinformations.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: ClusterInformation
    plural: clusterinformations
    singular: clusterinformation

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: globalnetworkpolicies.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: GlobalNetworkPolicy
    plural: globalnetworkpolicies
    singular: globalnetworkpolicy

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: globalnetworksets.crd.projectcalico.org
spec:
  scope: Cluster
  group: crd.projectcalico.org
  version: v1
  names:
    kind: GlobalNetworkSet
    plural: globalnetworksets
    singular: globalnetworkset

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: networkpolicies.crd.projectcalico.org
spec:
  scope: Namespaced
  group: crd.projectcalico.org
  version: v1
  names:
    kind: NetworkPolicy
    plural: networkpolicies
    singular: networkpolicy

---

apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
  name: networksets.crd.projectcalico.org
spec:
  scope: Namespaced
  group: crd.projectcalico.org
  version: v1
  names:
    kind: NetworkSet
    plural: networksets
    singular: networkset
---
# Source: calico/templates/rbac.yaml

# Include a clusterrole for the kube-controllers component,
# and bind it to the calico-kube-controllers serviceaccount.
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: calico-kube-controllers
rules:
  # Nodes are watched to monitor for deletions.
  - apiGroups: [""]
    resources:
      - nodes
    verbs:
      - watch
      - list
      - get
  # Pods are queried to check for existence.
  - apiGroups: [""]
    resources:
      - pods
    verbs:
      - get
  # IPAM resources are manipulated when nodes are deleted.
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - ippools
    verbs:
      - list
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - blockaffinities
      - ipamblocks
      - ipamhandles
    verbs:
      - get
      - list
      - create
      - update
      - delete
  # Needs access to update clusterinformations.
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - clusterinformations
    verbs:
      - get
      - create
      - update
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: calico-kube-controllers
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: calico-kube-controllers
subjects:
- kind: ServiceAccount
  name: calico-kube-controllers
  namespace: kube-system
---
# Include a clusterrole for the calico-node DaemonSet,
# and bind it to the calico-node serviceaccount.
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: calico-node
rules:
  # The CNI plugin needs to get pods, nodes, and namespaces.
  - apiGroups: [""]
    resources:
      - pods
      - nodes
      - namespaces
    verbs:
      - get
  - apiGroups: [""]
    resources:
      - endpoints
      - services
    verbs:
      # Used to discover service IPs for advertisement.
      - watch
      - list
      # Used to discover Typhas.
      - get
  - apiGroups: [""]
    resources:
      - nodes/status
    verbs:
      # Needed for clearing NodeNetworkUnavailable flag.
      - patch
      # Calico stores some configuration information in node annotations.
      - update
  # Watch for changes to Kubernetes NetworkPolicies.
  - apiGroups: ["networking.k8s.io"]
    resources:
      - networkpolicies
    verbs:
      - watch
      - list
  # Used by Calico for policy information.
  - apiGroups: [""]
    resources:
      - pods
      - namespaces
      - serviceaccounts
    verbs:
      - list
      - watch
  # The CNI plugin patches pods/status.
  - apiGroups: [""]
    resources:
      - pods/status
    verbs:
      - patch
  # Calico monitors various CRDs for config.
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - globalfelixconfigs
      - felixconfigurations
      - ippools
      - ipamblocks
      - globalnetworkpolicies
      - globalnetworksets
      - networkpolicies
      - networksets
      - clusterinformations
      - hostendpoints
      - blockaffinities
    verbs:
      - get
      - list
      - watch
  # Calico must create and update some CRDs on startup.
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - ippools
      - felixconfigurations
      - clusterinformations
    verbs:
      - create
      - update
  # Calico stores some configuration information on the node.
  - apiGroups: [""]
    resources:
      - nodes
    verbs:
      - get
      - list
      - watch
 
  # These permissions are required for Calico CNI to perform IPAM allocations.
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - blockaffinities
      - ipamblocks
      - ipamhandles
    verbs:
      - get
      - list
      - create
      - update
      - delete
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - ipamconfigs
    verbs:
      - get
  # Block affinities must also be watchable by confd for route aggregation.
  - apiGroups: ["crd.projectcalico.org"]
    resources:
      - blockaffinities
    verbs:
      - watch
  # The Calico IPAM migration needs to get daemonsets. These permissions can be
  # removed if not upgrading from an installation using host-local IPAM.
  - apiGroups: ["apps"]
    resources:
      - daemonsets
    verbs:
      - get
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: calico-node
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: calico-node
subjects:
- kind: ServiceAccount
  name: calico-node
  namespace: kube-system

---
# Source: calico/templates/calico-node.yaml
# This manifest installs the calico-node container, as well
# as the CNI plugins and network config on
# each master and worker node in a Kubernetes cluster.
kind: DaemonSet
apiVersion: apps/v1
metadata:
  name: calico-node
  namespace: kube-system
  labels:
    k8s-app: calico-node
spec:
  selector:
    matchLabels:
      k8s-app: calico-node
  updateStrategy:
    type: RollingUpdate
    rollingUpdate:
      maxUnavailable: 1
  template:
    metadata:
      labels:
        k8s-app: calico-node
      annotations:
        # This, along with the CriticalAddonsOnly toleration below,
        # marks the pod as a critical add-on, ensuring it gets
        # priority scheduling and that its resources are reserved
        # if it ever gets evicted.
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      nodeSelector:
        beta.kubernetes.io/os: linux
      hostNetwork: true
      tolerations:
        # Make sure calico-node gets scheduled on all nodes.
        - effect: NoSchedule
          operator: Exists
        # Mark the pod as a critical add-on for rescheduling.
        - key: CriticalAddonsOnly
          operator: Exists
        - effect: NoExecute
          operator: Exists
      serviceAccountName: calico-node
      # Minimize downtime during a rolling upgrade or deletion; tell Kubernetes to do a "force
      # deletion": https://kubernetes.io/docs/concepts/workloads/pods/pod/#termination-of-pods.
      terminationGracePeriodSeconds: 0
      priorityClassName: system-node-critical
      initContainers:
        # This container performs upgrade from host-local IPAM to calico-ipam.
        # It can be deleted if this is a fresh installation, or if you have already
        # upgraded to use calico-ipam.
        - name: upgrade-ipam
          image: calico/cni:v3.11.3
          command: ["/opt/cni/bin/calico-ipam", "-upgrade"]
          env:
            - name: KUBERNETES_NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            - name: CALICO_NETWORKING_BACKEND
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: calico_backend
          volumeMounts:
            - mountPath: /var/lib/cni/networks
              name: host-local-net-dir
            - mountPath: /host/opt/cni/bin
              name: cni-bin-dir
          securityContext:
            privileged: true
        # This container installs the CNI binaries
        # and CNI network config file on each node.
        - name: install-cni
          image: calico/cni:v3.11.3
          command: ["/install-cni.sh"]
          env:
            # Name of the CNI config file to create.
            - name: CNI_CONF_NAME
              value: "10-calico.conflist"
            # The CNI network config to install on each node.
            - name: CNI_NETWORK_CONFIG
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: cni_network_config
            # Set the hostname based on the k8s node name.
            - name: KUBERNETES_NODE_NAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            # CNI MTU Config variable
            - name: CNI_MTU
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: veth_mtu
            # Prevents the container from sleeping forever.
            - name: SLEEP
              value: "false"
          volumeMounts:
            - mountPath: /host/opt/cni/bin
              name: cni-bin-dir
            - mountPath: /host/etc/cni/net.d
              name: cni-net-dir
          securityContext:
            privileged: true
        # Adds a Flex Volume Driver that creates a per-pod Unix Domain Socket to allow Dikastes
        # to communicate with Felix over the Policy Sync API.
        - name: flexvol-driver
          image: calico/pod2daemon-flexvol:v3.11.3
          volumeMounts:
          - name: flexvol-driver-host
            mountPath: /host/driver
          securityContext:
            privileged: true
      containers:
        # Runs calico-node container on each Kubernetes node.  This
        # container programs network policy and routes on each
        # host.
        - name: calico-node
          image: calico/node:v3.11.3
          env:
            # Use Kubernetes API as the backing datastore.
            - name: DATASTORE_TYPE
              value: "kubernetes"
            # Wait for the datastore.
            - name: WAIT_FOR_DATASTORE
              value: "true"
            # Set based on the k8s node name.
            - name: NODENAME
              valueFrom:
                fieldRef:
                  fieldPath: spec.nodeName
            # Choose the backend to use.
            - name: CALICO_NETWORKING_BACKEND
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: calico_backend
            # Cluster type to identify the deployment type
            - name: CLUSTER_TYPE
              value: "k8s"
            # Enable IPIP
            - name: CALICO_IPV4POOL_VXLAN
              value: "Always"
            - name: CALICO_IPV6POOL_VXLAN
              value: "Always"
            # Set MTU for tunnel device used if ipip is enabled
            - name: FELIX_VXLAN
              valueFrom:
                configMapKeyRef:
                  name: calico-config
                  key: veth_mtu
            # The default IPv4 pool to create on startup if none exists. Pod IPs will be
            # chosen from this range. Changing this value after installation will have
            # no effect. This should fall within `--cluster-cidr`.
            - name: CALICO_IPV4POOL_CIDR
              value: "192.168.128.1/18"
            - name: CALICO_IPV6POOL_CIDR
              value: "fd00::/80"

            # Disable file logging so `kubectl logs` works.
            - name: CALICO_DISABLE_FILE_LOGGING
              value: "true"
            # Set Felix endpoint to host default action to ACCEPT.
            - name: FELIX_DEFAULTENDPOINTTOHOSTACTION
              value: "ACCEPT"
            # Disable IPv6 on Kubernetes.
            - name: FELIX_IPV6SUPPORT
              value: "true"
            # Set Felix logging to "info"
            - name: FELIX_LOGSEVERITYSCREEN
              value: "info"
            - name: FELIX_HEALTHENABLED
              value: "true"
          securityContext:
            privileged: true
          resources:
            requests:
              cpu: 250m
          livenessProbe:
            exec:
              command:
              - /bin/calico-node
              - -felix-live
              #- -bird-live
            periodSeconds: 10
            initialDelaySeconds: 10
            failureThreshold: 6
          readinessProbe:
            exec:
              command:
              - /bin/calico-node
              - -felix-ready
              #- -bird-ready
            periodSeconds: 10
          volumeMounts:
            - mountPath: /lib/modules
              name: lib-modules
              readOnly: true
            - mountPath: /run/xtables.lock
              name: xtables-lock
              readOnly: false
            - mountPath: /var/run/calico
              name: var-run-calico
              readOnly: false
            - mountPath: /var/lib/calico
              name: var-lib-calico
              readOnly: false
            - name: policysync
              mountPath: /var/run/nodeagent
      volumes:
        # Used by calico-node.
        - name: lib-modules
          hostPath:
            path: /lib/modules
        - name: var-run-calico
          hostPath:
            path: /var/run/calico
        - name: var-lib-calico
          hostPath:
            path: /var/lib/calico
        - name: xtables-lock
          hostPath:
            path: /run/xtables.lock
            type: FileOrCreate
        # Used to install CNI.
        - name: cni-bin-dir
          hostPath:
            path: /opt/cni/bin
        - name: cni-net-dir
          hostPath:
            path: /etc/cni/net.d
        # Mount in the directory for host-local IPAM allocations. This is
        # used when upgrading from host-local to calico-ipam, and can be removed
        # if not using the upgrade-ipam init container.
        - name: host-local-net-dir
          hostPath:
            path: /var/lib/cni/networks
        # Used to create per-pod Unix Domain Sockets
        - name: policysync
          hostPath:
            type: DirectoryOrCreate
            path: /var/run/nodeagent
        # Used to install Flex Volume Driver
        - name: flexvol-driver-host
          hostPath:
            type: DirectoryOrCreate
            path: /usr/libexec/kubernetes/kubelet-plugins/volume/exec/nodeagent~uds
---

apiVersion: v1
kind: ServiceAccount
metadata:
  name: calico-node
  namespace: kube-system

---
# Source: calico/templates/calico-kube-controllers.yaml

# See https://github.com/projectcalico/kube-controllers
apiVersion: apps/v1
kind: Deployment
metadata:
  name: calico-kube-controllers
  namespace: kube-system
  labels:
    k8s-app: calico-kube-controllers
spec:
  # The controllers can only have a single active instance.
  replicas: 1
  selector:
    matchLabels:
      k8s-app: calico-kube-controllers
  strategy:
    type: Recreate
  template:
    metadata:
      name: calico-kube-controllers
      namespace: kube-system
      labels:
        k8s-app: calico-kube-controllers
      annotations:
        scheduler.alpha.kubernetes.io/critical-pod: ''
    spec:
      nodeSelector:
        beta.kubernetes.io/os: linux
      tolerations:
        # Mark the pod as a critical add-on for rescheduling.
        - key: CriticalAddonsOnly
          operator: Exists
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
      serviceAccountName: calico-kube-controllers
      priorityClassName: system-cluster-critical
      containers:
        - name: calico-kube-controllers
          image: calico/kube-controllers:v3.11.3
          env:
            # Choose which controllers to run.
            - name: ENABLED_CONTROLLERS
              value: node
            - name: DATASTORE_TYPE
              value: kubernetes
          readinessProbe:
            exec:
              command:
              - /usr/bin/check-status
              - -r

---

apiVersion: v1
kind: ServiceAccount
metadata:
  name: calico-kube-controllers
  namespace: kube-system
---
# Source: calico/templates/calico-etcd-secrets.yaml

---
# Source: calico/templates/calico-typha.yaml

---
# Source: calico/templates/configure-canal.yaml
  

также я увидел, что все интерфейсы calico на хосте получили одинаковый ipv6
fe80::ecee: eeff:feee:eeee/64
какой шлюз ipv6 по умолчанию для всех модулей

также наблюдалось, что при включении vxlan не добавлялись маршруты vxlan.calico Link encap: Ethernet HWaddr 66:6a: cb:79:4e: d7 inet addr: 192.168.191.64 Bcast: 192.168.191.64 Маска: 255.255.255.255 inet6 addr: fe80::646a: cbff:fe79:4ed7 /64 Область действия: Широковещательное соединение ЗАПУЩЕННЫЙ МНОГОАДРЕСНЫЙ MTU: 1410 Показатель: 1 RX пакеты: 0 ошибки: 0 отброшены: 0 переполнения: 0 кадр: 0 TX пакеты: 0 ошибки: 0 отброшены: 125 переполнений: 0 несущая: 0 столкновения: 0 txqueuelen: 0 RX байты: 0 (0.0 B) TX байты: 0 (0.0 B) Флаги генмаски шлюза назначения Метрика Ref Использовать Iface по умолчанию _gateway 0.0.0.0 UG 0 0 0 eth0 10.243.0.0 * 255.255.224.0 U 0 0 0 eth0 192.168.0.0 * 255.255.192.0 U 0 0 0 eth0 192.168.191.70 * 255.255.255.255 UH 0 0 0 cali1c1c9f58b42 192.168.1971.71 * 255.255.255.255 UH 0 0 0 cali2fc31b4251c 192.168.19.72 * 255.255.255.255 UH 0 0 0 cali5be518cf856 192.168.1973 * 255.255.255.255 UH 0 0 0 cali5e3a68f7b5f 192.168.191.74 * 255.255.255.255 UH 0 0 0 cali59474b079db

Комментарии:

1. что вы имеете в виду под «выходом наружу»? Могут ли модули взаимодействовать друг с другом по протоколу ipv6?

2. модули не могут взаимодействовать друг с другом по ipv6, я хочу, чтобы контейнеры могли взаимодействовать с внешним миром (например, с каким-либо другим хостом в локальной сети с ipv6)

3. Kubernetes 1.15 и более ранних версий поддерживают только одну версию стека IP одновременно. Вы не можете использовать ipv4 и ipv6 одновременно.

4. ipip и vxlan режим оверлейной сети также не поддерживает ipv6.

Ответ №1:

Мы столкнулись с той же проблемой, с которой смогли связаться через ipv4, и не работаем с ipv6.

Мы сделали следующее,

 # Reset the Cluster
kubeadm reset

# Create the cluster by adding the ipv6 CIDR along with the ipv4 address also enable IPv6DualStack 
# NOTE: The ipv6 given below matches the first 4 octet with Host ipv6 address ie., fde1
kubeadm init --kubernetes-version=v1.21.1 --apiserver-advertise-address=172.16.2.1 --feature-gates="IPv6DualStack=true" --pod-network-cidr=172.16.0.0/24,fde1::/64 --service-cidr=172.16.1.0/24,fde1::/112

  

К настоящему времени мы будем видеть ipv6-адрес для интерфейсов во всех наших модулях, начинающихся с «fde1:»

Даже после настройки выше, мы не смогли выполнить пинг внешнего ipv6-адреса. Теперь мы обнаружили, что пакет достигает целевой машины и возвращается на хост-машину k8s, но не достиг соответствующего модуля.

Теперь мы обнаружили, что нам не хватает некоторых правил ip6tables. мы включаем natOuting в true, как показано ниже,

 # cat /etc/calico/default-ipv6-ippool.yaml
apiVersion: projectcalico.org/v3
kind: IPPool
metadata:
  name: default-ipv6-ippool
spec:
  blockSize: 122
  cidr: fde1::/64
  ipipMode: Never
  nodeSelector: all()
  natOutgoing: true
  vxlanMode: Never
# calicoctl apply -f /etc/calico/default-ipv6-ippool.yaml
  

Теперь выше создана запись в ip6tables, и мы можем выполнить пинг внешнего IPv6

Комментарии:

1. Спасибо за ответ, но в настоящее время у меня нет настройки k8s для проверки этого, также я только что наткнулся на еще одну ссылку github.com/projectcalico/calico/issues/2954 где они упомянули использовать переменную среды CALICO_IPV6POOL_NAT_OUTGOING= true вместо конфигурации, которая у вас есть, может быть, это будет полезно для вас. Когда я пробовал, это был k8s 1.14, который не поддерживал двойной стек.

2. Спасибо Ragav, не уверен, где применить это «CALICO_IPV6POOL_NAT_OUTGOING». мы пытались подать заявку под calico-node в calico.yaml, он не работает

Ответ №2:

Я общался по каналу slack calico и получил информацию о том, что мне нужно выполнить настройку для двойного стека для k8s и для calico

Комментарии:

1. Добавите ли вы подробности к своему ответу, чтобы он был полезен другим?