kubernetes笔记-用curl操作api

大多数K8S API资源类型是“objects”,代表群集上的概念的具体实例，如pod或namespace。少数API资源类型是virtual，通常表示操作而不是对象，例如权限检查。所有对象都将具有唯一的名称以允许幂等创建和检索，但如果virtual资源类型不可检索或不依赖于幂等，则virtual资源类型可能不具有唯一名称。

1.使用kubectl proxy访问

1.1.本地监听

启动kubectl proxy，不带任何参数只在本地监听，使用的是http协议,无需提供任何凭证就可以访问

kubectl proxy 
Starting to serve on 127.0.0.1:8001

验证api访问

curl http://127.0.0.1:8001/api/
{
  "kind": "APIVersions",
  "versions": [
    "v1"
  ],
  "serverAddressByClientCIDRs": [
    {
      "clientCIDR": "0.0.0.0/0",
      "serverAddress": "192.168.3.101:6443"
    }
  ]
}

1.2.网络监听

启动kubectl proxy，使用网卡IP，从其他机器访问， --accept-hosts='^*$' 表示接受所有源IP,否则会显示不被授权

kubectl proxy --address='192.168.3.101'  --accept-hosts='^*$' --port=8001   
Starting to serve on 192.168.3.101:8001
curl  http://192.168.3.101:8001/api/
{
  "kind": "APIVersions",
  "versions": [
    "v1"
  ],
  "serverAddressByClientCIDRs": [
    {
      "clientCIDR": "0.0.0.0/0",
      "serverAddress": "192.168.3.101:6443"
    }
  ]
}

2.直接访问api

2.1.获取集群名称和api地址

kubectl config view -o jsonpath='{"Cluster name\tServer\n"}{range .clusters[*]}{.name}{"\t"}{.cluster.server}{"\n"}{end}'
export CLUSTER_NAME="kubernetes"
APISERVER=$(kubectl config view -o jsonpath="{.clusters[?(@.name==\"$CLUSTER_NAME\")].cluster.server}")

2.2.使用serviceaccount来访问

创建serviceaccount并绑定集群角色cluster-admin

kubectl create serviceaccount  sa-panmeng 
kubectl create clusterrolebinding   sa-panmeng-cluster-admin --clusterrole='cluster-admin' --serviceaccount=default:sa-panmeng

获取serviceaccount sa-panmeng 的secret token

TOKEN=$(kubectl get secrets -o jsonpath="{.items[?(@.metadata.annotations['kubernetes\.io/service-account\.name']=='sa-panmeng')].data.token}"|base64 -d)

使用token访问api

curl --header "Authorization: Bearer $TOKEN" --insecure  -X GET $APISERVER/api/v1/namespaces/test/pods?limit=1
curl --header "Authorization: Bearer $TOKEN" --insecure  -X GET $APISERVER/api/v1/namespaces/default/pods?limit=1
curl --header "Authorization: Bearer $TOKEN" --insecure  -X GET $APISERVER/api/v1/namespaces/kube-system/pods?limit=1

serviceaccount虽然是区分namespace的，但是不影响使用这个token访问所有namespace的资源

2.3.使用useraccount来访问

创建user panmeng的证书

openssl genrsa -out panmeng.key 2048
openssl req -new -key panmeng.key -out panmeng.csr -subj "/CN=panmeng"
openssl x509 -req -in panmeng.csr -out panmeng.crt -sha1 -CA ca.crt -CAkey ca.key  -CAcreateserial -days 3650

创建角色getpods，创建角色绑定user panmeng和role getpods

kubectl create role getpods --verb=get --verb=list --resource=pods
kubectl create rolebinding panmeng-getpods --role=getpods --user=panmeng --namespace=default

验证访问是否正常

curl --cert /etc/kubernetes/pki/panmeng.crt   -X GET $APISERVER/api/v1/namespaces/default/pods?limit=1 --key /etc/kubernetes/pki/panmeng.key  --insecure

验证用户panmeng不具备访问namespace kube-system的权限

curl --cert /etc/kubernetes/pki/panmeng.crt   -X GET $APISERVER/api/v1/namespaces/kube-system/pods?limit=1 --key /etc/kubernetes/pki/panmeng.key  --insecure
{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {
    
  },
  "status": "Failure",
  "message": "pods is forbidden: User \"panmeng\" cannot list resource \"pods\" in API group \"\" in the namespace \"kube-system\"",
  "reason": "Forbidden",
  "details": {
    "kind": "pods"
  },
  "code": 403
}

3.常用api资源

以下为常用资源的URL路径，将/apis/GROUP/VERSION/替换为/api/v1/,则表示基础API组

/apis/GROUP/VERSION/RESOURCETYPE
/apis/GROUP/VERSION/RESOURCETYPE/NAME
/apis/GROUP/VERSION/namespaces/NAMESPACE/RESOURCETYPE
/apis/GROUP/VERSION/namespaces/NAMESPACE/RESOURCETYPE/NAME
/apis/GROUP/VERSION/RESOURCETYPE/NAME/SUBRESOURCE
/apis/GROUP/VERSION/namespaces/NAMESPACE/RESOURCETYPE/NAME/SUBRESOURCE

查看扩展api里的资源deployments

curl  http://127.0.0.1:8001/apis/extensions/v1beta1/namespaces/kube-system/deployments

查看基础api里的资源pods

curl  http://127.0.0.1:8001/api/v1/namespaces/kube-system/pods/

3.1.使用watch持续监控资源的变化

curl  http://127.0.0.1:8001/api/v1/namespaces/test/pods
"resourceVersion": "2563046"
curl  http://127.0.0.1:8001/api/v1/namespaces/test/pods?watch=1&resourceVersion=2563046

3.2.查看前n个资源

curl  http://127.0.0.1:8001/api/v1/namespaces/kube-system/pods?limit=1
"continue": "eyJ2IjoibWV0YS5rOHMuaW8vdjEiLCJydiI6MjU2NDk2Mywic3RhcnQiOiJjYWxpY28tbm9kZS1jejZrOVx1MDAwMCJ9"

使用continue token查看下n个资源

curl  'http://127.0.0.1:8001/api/v1/namespaces/kube-system/pods?limit=1&continue=eyJ2IjoibWV0YS5rOHMuaW8vdjEiLCJydiI6MjU3MTYxMSwic3RhcnQiOiJjYWxpY28ta3ViZS1jb250cm9sbGVycy01Y2JjY2NjODg1LWt2bGRyXHUwMDAwIn0'

4.资源的类型

资源分类：Workloads，Discovery & LB ，Config & Storage，Cluster，Metadata
资源对象：Resource ObjectMeta，ResourceSpec，ResourceStatus
资源操作：create，update（replace&patch），read（get&list&watch），delete,rollback,read/write scale,read/write status

5.Workloads的操作

以pod为例，介绍workloads apis，以下为pod的yaml文件

apiVersion: v1
kind: Pod
metadata:
  name: pod-example
spec:
  containers:
  - name: ubuntu
    image: ubuntu:trusty
    command: ["echo"]
    args: ["Hello World"]

5.1. 创建pod

POST /api/v1/namespaces/{namespace}/pods
查看当前pods

# kubectl -n test get pods
NAME       READY   STATUS             RESTARTS   AGE

使用api创建pod

curl --request POST http://127.0.0.1:8001/api/v1/namespaces/test/pods -s -w "状态码是:%{http_code}\n" -o /dev/null -H 'Content-Type: application/yaml' --data 'apiVersion: v1
kind: Pod
metadata:
  name: pod-example
spec:
  containers:
  - name: ubuntu
    image: ubuntu:trusty
    command: ["echo"]
    args: ["Hello World"]'
状态码是:201

查看当前pods

#kubectl -n test get pods
NAME          READY   STATUS              RESTARTS   AGE
pod-example   0/1     ContainerCreating   0          4s

状态码
200 Ok
201 Created
202 Accepted

5.2.删除pod

DELETE /api/v1/namespaces/{namespace}/pods/{name}
查看当前pods

kubectl get pods -n test --show-labels
NAME          READY   STATUS             RESTARTS   AGE     LABELS
pod-example   0/1     CrashLoopBackOff   1          15s

删除pod pod-example

curl --request DELETE http://127.0.0.1:8001/api/v1/namespaces/test/pods/pod-example -o /dev/null  -s -w "状态码是:%{http_code}\n" 
状态码是:200