Kubernetes控制平面初始化失败求助

执行kubeadm init初始化Kubernetes v1.25.0控制平面时，所有核心镜像拉取失败，提示dial tcp 34.107.244.51:443: i/o timeout。已确认Docker运行正常，kubectl和kubeadm命令可正常执行，想排查是Kubernetes侧问题还是操作失误。

错误日志 #

[init] Using Kubernetes version: v1.25.0
[preflight] Running pre-flight checks
[preflight] Pulling images required for setting up a Kubernetes cluster
[preflight] This might take a minute or two, depending on the speed of your internet connection
[preflight] You can also perform this action in beforehand using 'kubeadm config images pull'
error execution phase preflight: [preflight] Some fatal errors occurred:
    [ERROR ImagePull]: failed to pull image registry.k8s.io/kube-apiserver:v1.25.0: output: E0901 16:50:43.675142    4165 remote_image.go:218] "PullImage from image service failed" err="rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-apiserver:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-apiserver:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-apiserver/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout" image="registry.k8s.io/kube-apiserver:v1.25.0"
time="2022-09-01T16:50:43-06:00" level=fatal msg="pulling image: rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-apiserver:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-apiserver:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-apiserver/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout"
, error: exit status 1
    [ERROR ImagePull]: failed to pull image registry.k8s.io/kube-controller-manager:v1.25.0: output: E0901 16:53:14.264007    4564 remote_image.go:218] "PullImage from image service failed" err="rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-controller-manager:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-controller-manager:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-controller-manager/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout" image="registry.k8s.io/kube-controller-manager:v1.25.0"
time="2022-09-01T16:53:14-06:00" level=fatal msg="pulling image: rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-controller-manager:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-controller-manager:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-controller-manager/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout"
, error: exit status 1
    [ERROR ImagePull]: failed to pull image registry.k8s.io/kube-scheduler:v1.25.0: output: E0901 16:55:44.364804    4922 remote_image.go:218] "PullImage from image service failed" err="rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-scheduler:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-scheduler:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-scheduler/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout" image="registry.k8s.io/kube-scheduler:v1.25.0"
time="2022-09-01T16:55:44-06:00" level=fatal msg="pulling image: rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-scheduler:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-scheduler:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-scheduler/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout"
, error: exit status 1
    [ERROR ImagePull]: failed to pull image registry.k8s.io/kube-proxy:v1.25.0: output: E0901 16:58:14.769855    5295 remote_image.go:218] "PullImage from image service failed" err="rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-proxy:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-proxy:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-proxy/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout" image="registry.k8s.io/kube-proxy:v1.25.0"
time="2022-09-01T16:58:14-06:00" level=fatal msg="pulling image: rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/kube-proxy:v1.25.0\": failed to resolve reference \"registry.k8s.io/kube-proxy:v1.25.0\": failed to do request: Head https://registry.k8s.io/v2/kube-proxy/manifests/v1.25.0: dial tcp 34.107.244.51:443: i/o timeout"
, error: exit status 1
    [ERROR ImagePull]: failed to pull image registry.k8s.io/etcd:3.5.4-0: output: E0901 17:03:14.966455    6024 remote_image.go:218] "PullImage from image service failed" err="rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/etcd:3.5.4-0\": failed to resolve reference \"registry.k8s.io/etcd:3.5.4-0\": failed to do request: Head https://registry.k8s.io/v2/etcd/manifests/3.5.4-0: dial tcp 34.107.244.51:443: i/o timeout" image="registry.k8s.io/etcd:3.5.4-0"
time="2022-09-01T17:03:14-06:00" level=fatal msg="pulling image: rpc error: code = Unknown desc = failed to pull and unpack image \"registry.k8s.io/etcd:3.5.4-0\": failed to resolve reference \"registry.k8s.io/etcd:3.5.4-0\": failed to do request: Head https://registry.k8s.io/v2/etcd/manifests/3.5.4-0: dial tcp 34.107.244.51:443: i/o timeout"
, error: exit status 1
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`
To see the stack trace of this error execute with --v=5 or higher

问题分析 #

这既不是操作失误，也不是Kubernetes本身的问题，核心原因是网络连接超时：服务器无法正常连接到registry.k8s.io官方镜像仓库（对应IP 34.107.244.51），导致所有控制平面核心镜像拉取失败。

解决方法 #

• 使用国内镜像源替换官方仓库
  执行kubeadm init时直接指定国内镜像仓库（比如阿里云），避免连接官方仓库的网络问题：

  kubeadm init --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.25.0
  

  也可以先单独拉取所有镜像，再执行初始化：

  kubeadm config images pull --image-repository registry.aliyuncs.com/google_containers --kubernetes-version v1.25.0
  

• 检查网络连通性与限制
  测试服务器是否能访问官方镜像仓库：

  curl -v https://registry.k8s.io/v2/
  

  如果无法访问，检查服务器是否有防火墙规则、代理配置或网络策略限制了对外连接，调整后重试。

• 手动拉取镜像并重命名
  从可访问的第三方仓库拉取镜像，再修改标签为官方仓库名称，让kubeadm识别：
  示例（以阿里云仓库为例）：

  # 拉取镜像
  docker pull registry.aliyuncs.com/google_containers/kube-apiserver:v1.25.0
  docker pull registry.aliyuncs.com/google_containers/kube-controller-manager:v1.25.0
  docker pull registry.aliyuncs.com/google_containers/kube-scheduler:v1.25.0
  docker pull registry.aliyuncs.com/google_containers/kube-proxy:v1.25.0
  docker pull registry.aliyuncs.com/google_containers/etcd:3.5.4-0
  docker pull registry.aliyuncs.com/google_containers/pause:3.8
  
  # 重命名镜像标签
  docker tag registry.aliyuncs.com/google_containers/kube-apiserver:v1.25.0 registry.k8s.io/kube-apiserver:v1.25.0
  docker tag registry.aliyuncs.com/google_containers/kube-controller-manager:v1.25.0 registry.k8s.io/kube-controller-manager:v1.25.0
  docker tag registry.aliyuncs.com/google_containers/kube-scheduler:v1.25.0 registry.k8s.io/kube-scheduler:v1.25.0
  docker tag registry.aliyuncs.com/google_containers/kube-proxy:v1.25.0 registry.k8s.io/kube-proxy:v1.25.0
  docker tag registry.aliyuncs.com/google_containers/etcd:3.5.4-0 registry.k8s.io/etcd:3.5.4-0
  docker tag registry.aliyuncs.com/google_containers/pause:3.8 registry.k8s.io/pause:3.8
  

  完成后再执行kubeadm init即可。

内容的提问来源于stack exchange，提问作者user19899551