一直有这个冲动，
想知道kubernetes往etcd里放了哪些数据，是如何组织的。
能看到，才有把握知道它的实现和细节。
找了很多文档，终于找到靠谱的。
===========================
https://www.jianshu.com/p/f9f83dd21770
===========================
操作etcd有命令行工具 etcdctl，有两个api版本互不兼容的，系统默认的v2版本，kubernetes集群使用的是v3版本，v2版本下是看不到v3版本的数据的，我也是找了些资料才了解这个情况。
使用环境变量定义api版本
export ETCDCTL_API=3
etcd有目录结构类似linux文件系统，获取所有key看一看：
etcdctl get / --prefix --keys-only
一看就可以大概理解kubenetes的数据结构了，查询命名空间下所有部署的数据：
etcdctl get /registry/deployments/default --prefix --keys-only
etcdctl del /registry/deployments/default/elevated-dragonfly-spinn-front50
删除deployments，pods这可以了，稍微减少一些资源，让kube-apiserver可以正常工作即可，其它资源还可以使用kubectl工具删除
删掉些资源后退出etcd把kube-apiserver的编排文件放回/etc/kubernetes/manifests目录，服务会再次启动，然后再清理重新部署。
=======================================
etcdctl get / --prefix --keys-only
/registry/apiregistration.k8s.io/apiservices/v1.
/registry/apiregistration.k8s.io/apiservices/v1.apps
/registry/apiregistration.k8s.io/apiservices/v1.authentication.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1.authorization.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1.autoscaling
/registry/apiregistration.k8s.io/apiservices/v1.batch
/registry/apiregistration.k8s.io/apiservices/v1.networking.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1.rbac.authorization.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1.storage.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.admissionregistration.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.apiextensions.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.apps
/registry/apiregistration.k8s.io/apiservices/v1beta1.authentication.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.authorization.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.batch
/registry/apiregistration.k8s.io/apiservices/v1beta1.certificates.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.events.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.extensions
/registry/apiregistration.k8s.io/apiservices/v1beta1.policy
/registry/apiregistration.k8s.io/apiservices/v1beta1.rbac.authorization.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta1.storage.k8s.io
/registry/apiregistration.k8s.io/apiservices/v1beta2.apps
/registry/apiregistration.k8s.io/apiservices/v2beta1.autoscaling
/registry/certificatesigningrequests/node-csr-NMpLG7rhBYiuAyRD739h79x2qhbhWn-UtLPFwJWJU1Y
/registry/certificatesigningrequests/node-csr-v96LRHUfeRD3iAZgHdUYxDaT1kkHvIilDnLZy2GPSew
/registry/clusterrolebindings/cluster-admin
/registry/clusterrolebindings/flannel
/registry/clusterrolebindings/heapster
/registry/clusterrolebindings/kubeadm:kubelet-bootstrap
/registry/clusterrolebindings/kubeadm:node-autoapprove-bootstrap
/registry/clusterrolebindings/kubeadm:node-autoapprove-certificate-rotation
/registry/clusterrolebindings/kubeadm:node-proxier
/registry/clusterrolebindings/kubernetes-dashboard
/registry/clusterrolebindings/system:aws-cloud-provider
/registry/clusterrolebindings/system:basic-user
/registry/clusterrolebindings/system:controller:attachdetach-controller
/registry/clusterrolebindings/system:controller:certificate-controller
/registry/clusterrolebindings/system:controller:clusterrole-aggregation-controller
/registry/clusterrolebindings/system:controller:cronjob-controller
/registry/clusterrolebindings/system:controller:daemon-set-controller
/registry/clusterrolebindings/system:controller:deployment-controller
/registry/clusterrolebindings/system:controller:disruption-controller
/registry/clusterrolebindings/system:controller:endpoint-controller
/registry/clusterrolebindings/system:controller:generic-garbage-collector
/registry/clusterrolebindings/system:controller:horizontal-pod-autoscaler
/registry/clusterrolebindings/system:controller:job-controller
/registry/clusterrolebindings/system:controller:namespace-controller
/registry/clusterrolebindings/system:controller:node-controller
/registry/clusterrolebindings/system:controller:persistent-volume-binder
/registry/clusterrolebindings/system:controller:pod-garbage-collector
/registry/clusterrolebindings/system:controller:replicaset-controller
/registry/clusterrolebindings/system:controller:replication-controller
/registry/clusterrolebindings/system:controller:resourcequota-controller
/registry/clusterrolebindings/system:controller:route-controller
/registry/clusterrolebindings/system:controller:service-account-controller
/registry/clusterrolebindings/system:controller:service-controller
/registry/clusterrolebindings/system:controller:statefulset-controller
/registry/clusterrolebindings/system:controller:ttl-controller
/registry/clusterrolebindings/system:coredns
/registry/clusterrolebindings/system:discovery
/registry/clusterrolebindings/system:kube-controller-manager
/registry/clusterrolebindings/system:kube-dns
/registry/clusterrolebindings/system:kube-scheduler
/registry/clusterrolebindings/system:node
/registry/clusterrolebindings/system:node-proxier
/registry/clusterroles/admin
/registry/clusterroles/cluster-admin
/registry/clusterroles/edit
/registry/clusterroles/flannel
/registry/clusterroles/system:aggregate-to-admin
/registry/clusterroles/system:aggregate-to-edit
/registry/clusterroles/system:aggregate-to-view
/registry/clusterroles/system:auth-delegator
/registry/clusterroles/system:aws-cloud-provider
/registry/clusterroles/system:basic-user
/registry/clusterroles/system:certificates.k8s.io:certificatesigningrequests:nodeclient
/registry/clusterroles/system:certificates.k8s.io:certificatesigningrequests:selfnodeclient
/registry/clusterroles/system:controller:attachdetach-controller
/registry/clusterroles/system:controller:certificate-controller
/registry/clusterroles/system:controller:clusterrole-aggregation-controller
/registry/clusterroles/system:controller:cronjob-controller
/registry/clusterroles/system:controller:daemon-set-controller
/registry/clusterroles/system:controller:deployment-controller
/registry/clusterroles/system:controller:disruption-controller
/registry/clusterroles/system:controller:endpoint-controller
/registry/clusterroles/system:controller:generic-garbage-collector
/registry/clusterroles/system:controller:horizontal-pod-autoscaler
/registry/clusterroles/system:controller:job-controller
/registry/clusterroles/system:controller:namespace-controller
/registry/clusterroles/system:controller:node-controller
/registry/clusterroles/system:controller:persistent-volume-binder
/registry/clusterroles/system:controller:pod-garbage-collector
/registry/clusterroles/system:controller:replicaset-controller
/registry/clusterroles/system:controller:replication-controller
/registry/clusterroles/system:controller:resourcequota-controller
/registry/clusterroles/system:controller:route-controller
/registry/clusterroles/system:controller:service-account-controller
/registry/clusterroles/system:controller:service-controller
/registry/clusterroles/system:controller:statefulset-controller
/registry/clusterroles/system:controller:ttl-controller
/registry/clusterroles/system:coredns
/registry/clusterroles/system:discovery
/registry/clusterroles/system:heapster
/registry/clusterroles/system:kube-aggregator
/registry/clusterroles/system:kube-controller-manager
/registry/clusterroles/system:kube-dns
/registry/clusterroles/system:kube-scheduler
/registry/clusterroles/system:node
/registry/clusterroles/system:node-bootstrapper
/registry/clusterroles/system:node-problem-detector
/registry/clusterroles/system:node-proxier
/registry/clusterroles/system:persistent-volume-provisioner
/registry/clusterroles/view
/registry/configmaps/kube-public/cluster-info
/registry/configmaps/kube-system/coredns
/registry/configmaps/kube-system/extension-apiserver-authentication
/registry/configmaps/kube-system/kube-flannel-cfg
/registry/configmaps/kube-system/kube-proxy
/registry/configmaps/kube-system/kubeadm-config
/registry/configmaps/kube-system/kubernetes-dashboard-settings
/registry/controllerrevisions/kube-system/kube-flannel-ds-dd8484577
/registry/controllerrevisions/kube-system/kube-proxy-95cfb667c
/registry/cronjobs/default/hello
/registry/daemonsets/kube-system/kube-flannel-ds
/registry/daemonsets/kube-system/kube-proxy
/registry/deployments/default/flower
/registry/deployments/default/pc-saveapi
/registry/deployments/default/pxxxm-django
/registry/deployments/default/pxxxm-redis
/registry/deployments/default/pxxxm-tengine-proxy
/registry/deployments/default/pxxxm-tengine-static
/registry/deployments/default/pxxxmlogapi-nj
/registry/deployments/kube-system/coredns
/registry/deployments/kube-system/heapster
/registry/deployments/kube-system/kubernetes-dashboard
/registry/deployments/kube-system/monitoring-grafana
/registry/deployments/kube-system/monitoring-influxdb
/registry/events/default/flower-554b58b968-n48sj.151de36ccc190d41
/registry/events/default/flower-554b58b968-n48sj.151de36e0d128ca9
/registry/events/default/hello.151e1bcd521ee391
/registry/jobs/default/hello-1521622920
/registry/jobs/default/hello-1521622980
/registry/jobs/default/hello-1521623040
/registry/minions/cnsz131381
/registry/minions/cnsz131382
/registry/minions/cnsz131383
/registry/namespaces/default
/registry/namespaces/kube-public
/registry/namespaces/kube-system
/registry/pods/default/flower-554b58b968-n48sj
/registry/pods/default/hello-1521622920-5z4bl
/registry/pods/default/hello-1521622980-4qcrd
/registry/pods/default/hello-1521623040-szf4f
/registry/pods/default/pc-saveapi-58cf87b4f5-5x2d8
/registry/pods/default/pxxxm-django-8466f46d84-4mjtf
/registry/pods/default/pxxxm-django-8466f46d84-pnqzp
/registry/pods/default/pxxxm-django-8466f46d84-x5d8z
/registry/pods/default/pxxxm-redis-767c5d5966-l88qj
/registry/pods/default/pxxxm-tengine-proxy-75d874d898-8275h
/registry/pods/default/pxxxm-tengine-static-7d7bb5d5b6-7568z
/registry/pods/default/pxxxmlogapi-nj-687cc89b96-ps4np
/registry/pods/kube-system/coredns-65dcdb4cf-hgmdv
/registry/pods/kube-system/etcd-cnsz131383
/registry/pods/kube-system/heapster-5996df699d-d8798
/registry/pods/kube-system/kube-apiserver-cnsz131383
/registry/pods/kube-system/kube-controller-manager-cnsz131383
/registry/pods/kube-system/kube-flannel-ds-gr8jp
/registry/pods/kube-system/kube-flannel-ds-p4tpq
/registry/pods/kube-system/kube-flannel-ds-z7s96
/registry/pods/kube-system/kube-proxy-cgjhk
/registry/pods/kube-system/kube-proxy-f7snz
/registry/pods/kube-system/kube-proxy-l98gl
/registry/pods/kube-system/kube-scheduler-cnsz131383
/registry/pods/kube-system/kubernetes-dashboard-5bd6f767c7-vr6sg
/registry/pods/kube-system/monitoring-grafana-6bf544559d-cd6d4
/registry/pods/kube-system/monitoring-influxdb-865d95895b-n9sls
/registry/ranges/serviceips
/registry/ranges/servicenodeports
/registry/replicasets/default/flower-554b58b968
/registry/replicasets/default/pc-saveapi-58cf87b4f5
/registry/replicasets/default/pxxxm-django-8466f46d84
/registry/replicasets/default/pxxxm-redis-767c5d5966
/registry/replicasets/default/pxxxm-tengine-proxy-75d874d898
/registry/replicasets/default/pxxxm-tengine-static-7d7bb5d5b6
/registry/replicasets/default/pxxxmlogapi-nj-687cc89b96
/registry/replicasets/kube-system/coredns-65dcdb4cf
/registry/replicasets/kube-system/heapster-5996df699d
/registry/replicasets/kube-system/kubernetes-dashboard-5bd6f767c7
/registry/replicasets/kube-system/monitoring-grafana-6bf544559d
/registry/replicasets/kube-system/monitoring-influxdb-865d95895b
/registry/rolebindings/kube-public/kubeadm:bootstrap-signer-clusterinfo
/registry/rolebindings/kube-public/system:controller:bootstrap-signer
/registry/rolebindings/kube-system/kubernetes-dashboard-minimal
/registry/rolebindings/kube-system/system::leader-locking-kube-controller-manager
/registry/rolebindings/kube-system/system::leader-locking-kube-scheduler
/registry/rolebindings/kube-system/system:controller:bootstrap-signer
/registry/rolebindings/kube-system/system:controller:cloud-provider
/registry/rolebindings/kube-system/system:controller:token-cleaner
/registry/roles/kube-public/kubeadm:bootstrap-signer-clusterinfo
/registry/roles/kube-public/system:controller:bootstrap-signer
/registry/roles/kube-system/extension-apiserver-authentication-reader
/registry/roles/kube-system/kubernetes-dashboard-minimal
/registry/roles/kube-system/system::leader-locking-kube-controller-manager
/registry/roles/kube-system/system::leader-locking-kube-scheduler
/registry/roles/kube-system/system:controller:bootstrap-signer
/registry/roles/kube-system/system:controller:cloud-provider
/registry/roles/kube-system/system:controller:token-cleaner
/registry/secrets/default/default-token-hfj82
/registry/secrets/kube-public/default-token-wpbfs
/registry/secrets/kube-system/attachdetach-controller-token-7jsks
/registry/secrets/kube-system/bootstrap-signer-token-xs87g
/registry/secrets/kube-system/certificate-controller-token-x4swr
/registry/secrets/kube-system/clusterrole-aggregation-controller-token-z7w85
/registry/secrets/kube-system/coredns-token-tbbbw
/registry/secrets/kube-system/cronjob-controller-token-p44bn
/registry/secrets/kube-system/daemon-set-controller-token-4klc2
/registry/secrets/kube-system/default-token-g9lcp
/registry/secrets/kube-system/deployment-controller-token-gfcdt
/registry/secrets/kube-system/disruption-controller-token-vs4dz
/registry/secrets/kube-system/endpoint-controller-token-92kn2
/registry/secrets/kube-system/flannel-token-wvgjq
/registry/secrets/kube-system/generic-garbage-collector-token-pcpnq
/registry/secrets/kube-system/heapster-token-6szhz
/registry/secrets/kube-system/horizontal-pod-autoscaler-token-xqcl5
/registry/secrets/kube-system/job-controller-token-422zr
/registry/secrets/kube-system/kube-proxy-token-k5rfq
/registry/secrets/kube-system/kubernetes-dashboard-certs
/registry/secrets/kube-system/kubernetes-dashboard-key-holder
/registry/secrets/kube-system/kubernetes-dashboard-token-kpkw7
/registry/secrets/kube-system/namespace-controller-token-r57ss
/registry/secrets/kube-system/node-controller-token-5f7sm
/registry/secrets/kube-system/persistent-volume-binder-token-7rnt2
/registry/secrets/kube-system/pod-garbage-collector-token-2txwf
/registry/secrets/kube-system/replicaset-controller-token-zh9xq
/registry/secrets/kube-system/replication-controller-token-q69jz
/registry/secrets/kube-system/resourcequota-controller-token-92hn4
/registry/secrets/kube-system/service-account-controller-token-vvw5d
/registry/secrets/kube-system/service-controller-token-lslnf
/registry/secrets/kube-system/statefulset-controller-token-wdqjt
/registry/secrets/kube-system/token-cleaner-token-9zzpv
/registry/secrets/kube-system/ttl-controller-token-tc7pl
/registry/serviceaccounts/default/default
/registry/serviceaccounts/kube-public/default
/registry/serviceaccounts/kube-system/attachdetach-controller
/registry/serviceaccounts/kube-system/bootstrap-signer
/registry/serviceaccounts/kube-system/certificate-controller
/registry/serviceaccounts/kube-system/clusterrole-aggregation-controller
/registry/serviceaccounts/kube-system/coredns
/registry/serviceaccounts/kube-system/cronjob-controller
/registry/serviceaccounts/kube-system/daemon-set-controller
/registry/serviceaccounts/kube-system/default
/registry/serviceaccounts/kube-system/deployment-controller
/registry/serviceaccounts/kube-system/disruption-controller
/registry/serviceaccounts/kube-system/endpoint-controller
/registry/serviceaccounts/kube-system/flannel
/registry/serviceaccounts/kube-system/generic-garbage-collector
/registry/serviceaccounts/kube-system/heapster
/registry/serviceaccounts/kube-system/horizontal-pod-autoscaler
/registry/serviceaccounts/kube-system/job-controller
/registry/serviceaccounts/kube-system/kube-proxy
/registry/serviceaccounts/kube-system/kubernetes-dashboard
/registry/serviceaccounts/kube-system/namespace-controller
/registry/serviceaccounts/kube-system/node-controller
/registry/serviceaccounts/kube-system/persistent-volume-binder
/registry/serviceaccounts/kube-system/pod-garbage-collector
/registry/serviceaccounts/kube-system/replicaset-controller
/registry/serviceaccounts/kube-system/replication-controller
/registry/serviceaccounts/kube-system/resourcequota-controller
/registry/serviceaccounts/kube-system/service-account-controller
/registry/serviceaccounts/kube-system/service-controller
/registry/serviceaccounts/kube-system/statefulset-controller
/registry/serviceaccounts/kube-system/token-cleaner
/registry/serviceaccounts/kube-system/ttl-controller
/registry/services/endpoints/default/flower
/registry/services/endpoints/default/kubernetes
/registry/services/endpoints/default/pc-saveapi
/registry/services/endpoints/default/pxxxm-django
/registry/services/endpoints/default/pxxxm-redis
/registry/services/endpoints/default/pxxxm-tengine-proxy
/registry/services/endpoints/default/pxxxm-tengine-static
/registry/services/endpoints/default/pxxxmlogapi-nj
/registry/services/endpoints/kube-system/heapster
/registry/services/endpoints/kube-system/kube-controller-manager
/registry/services/endpoints/kube-system/kube-dns
/registry/services/endpoints/kube-system/kube-scheduler
/registry/services/endpoints/kube-system/kubernetes-dashboard
/registry/services/endpoints/kube-system/monitoring-grafana
/registry/services/endpoints/kube-system/monitoring-influxdb
/registry/services/specs/default/flower
/registry/services/specs/default/kubernetes
/registry/services/specs/default/pc-saveapi
/registry/services/specs/default/pxxxm-django
/registry/services/specs/default/pxxxm-redis
/registry/services/specs/default/pxxxm-tengine-proxy
/registry/services/specs/default/pxxxm-tengine-static
/registry/services/specs/default/pxxxmlogapi-nj
/registry/services/specs/kube-system/heapster
/registry/services/specs/kube-system/kube-dns
/registry/services/specs/kube-system/kubernetes-dashboard
/registry/services/specs/kube-system/monitoring-grafana
/registry/services/specs/kube-system/monitoring-influxdb
