Kubernetes集群安全配置

更多关于kubernetes的深入文章，请看我csdn或者oschina的博客主页。

这两天在梳理Kubernetes集群的安全配置，涉及到各个组件的配置，最终决定画一个图来展现，应该会更清晰。

涉及以下配置：

其他各个组件作为client，访问kube-apiserver时，各个组件的配置，参考图中黑色线条对应的配置：

kube-apiserver

--secure-port=443 --client_ca_file=/var/run/kubernetes/dd_ca.crt --tls-private-key-file=/var/run/kubernetes/dd_server.key

kube-controller-manager

``` --kubeconfig=/etc/kubernetes/cmkubeconfig apiVersion: v1 kind: Config users - name: controllermanager user: client-certificate: /var/run/kubernetes/dd_cs_client.crt client-key: /var/run/kubernetes/dd_cs_client.key clusters: - name: local cluster: certificate-authority: /var/run/kubernetes/dd_ca.crt contexts: - context: cluster: local user: controllermanager name: my-context current-context: my-context ```

kube-scheduler kube-scheduler访问apiserver的安全配置同kube-controller-manager。

kubelet

--kubeconfig=/var/lib/kubelet/kubeconfig apiVersion: v1 kind: Config users: - name: kubelet user: client-certificats: /home/dd_kubelet_client.crt client-key: /home/dd_kubelet_client.key clusters: - name: local cluster: certificate-authority: /home/dd_ca.crt contexts: - context: cluster: local user: kubelet name: my-context current-context: my-context

kube-proxy

--kubeconfig=/var/lib/kubeproxy/proxykubeconfig apiVersion: v1 kind: Config users: - name: kubeproxy user: client-certificate: /home/dd_kubelet_client.crt client-key: /home/dd_kubelet_client.key clusters: - name: local cluster: certificate-authority: /home/dd_ca.crt contexts: - context: cluster: local user: kubeproxy name: my-context current-context: my-context

kube-apiserver作为client，访问kubelet server时的配置，参考图中绿色线条对应的配置：

kube-apiserver

--kubelet-https --kubelet-certificate-authority=/var/run/kubelet/kubelet-ca.crt --kubelet-client-certificate=/var/run/kubelet/apiserver-kubelet.crt --kubelet-client-key=/var/run/kubelet/apiserver-kubelet.key

kubelet

--client-ca-file=/var/run/kubelet/kubelet_ca.crt --tls-private-key-file=/var/run/kubelet/server.key --tls-cert-file string=/var/run/kubelet/server.crt

Pod访问kube-apiserver，是通过ServiceAccount来提供Token的, 涉及的配置见粉红色线条对应的内容。

Pod.Spec

每个namespace都有一个default ServiceAccount。如果Pod.Spec.serivceAccountName未设置，这默认用default ServiceAccount。上图中的配置中，给Pod指明了一个自定义的Pod.Spec.serivceAccountName:build-rebot，automountServiceAccountToken: true表示自动将该ServiceAccount中的Secret定义的token,ca.crt,namespace挂载到Pod每个container内的以下对应目录：

ServiceAccount Admission Make Sure Secret Volume Mounted: /var/run/secrets/kubernetes.io/serviceaccount/token /var/run/secrets/kubernetes.io/serviceaccount/ca.crt /var/run/secrets/kubernetes.io/serviceaccount/namespace

kube-controller-manager

--root-ca-file=/var/run/kubernetes/dd_ca.crt --service-account-private-key-file=/var/run/kubernetes/dd_server.key

这样Pod内的应用就能通过以下两种方式访问apiserver了：

添加kubectl proxy container，示例见kubectl-containeruse the Go client library, and create a client using the rest.InClusterConfig() and kubernetes.NewForConfig() functions. They handle locating and authenticating to the apiserver. example

kube-apiserver作为client，通过TLS访问etcd对应的配置见图中蓝色线条对应的内容。

kube-apiserver

--etcd-cafile=/var/run/etcd/etcd-ca.crt --etcd-certfile=/var/run/etcd/apiserver-etcd.crt --etcd-keyfile=/var/run/etcd/apiserver-etcd.key

etcd

--client-cert-auth --trusted-ca-file=/etc/ssl/etcd/etcd-ca.crt --cert-file=/etc/ssl/etcd/server.crt --key-file=/etc/ssl/etcd/server.key

apiserver的Authentication Config：

kube-apiserver 以下三个flag，分别表示enable apiserver的x509 client certs, static token, static password三种认证方式。

--client-ca-file=/var/run/kubernetes/dd_ca.crt --token-auth-file=SOMEFILE --basic-auth-file=SOMEFILE

其中token-auth-file对应文件内容格式为：

token1,user1,uid1,”group1,group2,group3" token2,user2,uid2,”group1,group2"

basic-auth-file对应文件内容格式为：

password1,user1,uid1,”group1,group2,group3" password2,user2,uid2,”group1,group2,group3"

apiserver的Authorization Config：

kube-apiserver 当前我们的环境中，使用默认值AlwaysAllow，如果有需要，后续会考虑enable RBAC。

--authorization-mode=AlwaysAllow

apiserver的Admission Control Config：

kube-apiserver 使用官方推荐的，v1.6+之后的配置为：

--admission-control=NamespaceLifecycle, LimitRanger, ServiceAccount, PersistentVolumeLabel, DefaultStorageClass, ResourceQuota, DefaultTolerationSeconds

更多关于kubernetes的深入文章，请看我csdn或者oschina的博客主页。