Kubernetes Python客户端:身份验证问题 [英] Kubernetes python client: authentication issue

问题描述

我们将kubernetes python客户端(4.0.0)与Google的kubernetes引擎(主+节点池运行k8s 1.8.4)结合使用，以定期计划kubernetes上的工作负载.用于创建Pod，将其附加到日志并报告Pod的结束状态的脚本的简化版本如下:

We are using the kubernetes python client (4.0.0) in combination with google's kubernetes engine (master + nodepools run k8s 1.8.4) to periodically schedule workloads on kubernetes. The simplified version of the script we use to creates the pod, attach to the the logs and report the end status of the pod looks as follows:

config.load_kube_config(persist_config=False)
v1 = client.CoreV1Api()
v1.create_namespaced_pod(body=pod_specs_dict, namespace=args.namespace)
logging_response = v1.read_namespaced_pod_log(
    name=pod_name,
    namespace=args.namespace,
    follow=True,
    _preload_content=False
)
for line in logging_response:
    line = line.rstrip()
    logging.info(line)
status_response = v1.read_namespaced_pod_status(pod_name, namespace=args.namespace)
print("Pod ended in status: {}".format(status_response.status.phase))

一切正常，但是我们遇到了一些身份验证问题.身份验证通过默认的gcp身份验证提供程序进行，我通过在调度程序上手动运行kubectl container cluster get-credentials获得了初始访问令牌.在某些随机时间范围内，某些API调用会导致来自API服务器的401响应.我的猜测是，只要访问令牌过期，并且脚本尝试获取新的访问令牌，就会发生这种情况.但是，碰巧在调度程序上同时运行多个脚本，导致多次获得一个新的API密钥，而其中只有一个仍然有效.我尝试了多种方法来解决此问题(使用persist_config=True，重新加载配置后重试401，...)，但没有成功.由于我还不完全了解gcp身份验证和kubernetes python客户端配置的工作方式(而且两者的文档都相当稀缺)，所以我有点不知所措.

Everything works pretty fine, however we are experiencing some authentication issues. Authentication happens through the default gcp auth-provider, for which I obtained the initial access token by running a kubectl container cluster get-credentials manually on the scheduler. At some random timeframes, some API calls result in a 401 response from the API server. My guess is that this happens whenever the access token is expired, and the script tries to obtain a new access token. However it happens that multiple scripts are running concurrently on the scheduler, resulting in obtaining a new API key multiple times of which only one is still valid. I tried out multiple ways to fix the issue (use persist_config=True, retry 401's after reloading the config,...) without any success. As I am not completely aware how the gcp authentication and the kubernetes python client config work (and docs for both are rather scarce), I am a bit left in the dark.

我们应该使用其他身份验证方法代替gcp auth-provider吗?这是kubernetes python客户端中的错误吗?我们应该使用多个配置文件吗?

Should we use another authentication method instead of the gcp auth-provider? Is this a bug in the kubernetes python client? Should we use multiple config files?

推荐答案

最后，我们通过使用承载令牌身份验证解决了这一问题，而不是依靠默认的gcloud身份验证方法.

In the end we have solved this by using bearer token authentication, instead of relying on the default gcloud authentication method.

这是我为实现这一目标而采取的步骤.

Here are the steps that I did to achieve this.

首先通过创建具有以下内容的文件，在所需的名称空间中创建服务帐户.

First create a service account in the desired namespace, by creating a file with the following content.

apiVersion: v1
kind: ServiceAccount
metadata:
  name: <name_of_service_account>

然后使用此文件创建服务帐户

Then use this file to create the service account

kubectl create -f <path_to_file> --namespace=<namespace_name>

每个服务帐户都有一个链接的承载令牌，可用于身份验证.该承载令牌自动作为秘密安装到命名空间中.要找出此令牌是什么，请首先找到密钥的名称(格式为<service_account_name>-token-<random_string>)，然后使用该名称获取内容.

Each service account has a bearer token linked to it, which can be used for authentication. This bearer token is automatically mounted as a secret into the namespace. To find out what this token is, first find the name of the secret (is of the form <service_account_name>-token-<random_string>) and then use that name to get to content.

# To search for out service account's token name
kubectl get secrets --namespace=<namespace_name>

# To find the token name
kubectl describe secret/<secret_name>

此后，您应该找到API服务器的IP地址以及kubernetes集群的集群CA证书.这可以通过转到Google Cloud Console上的kubernetes引擎详细信息页面来完成.将证书的内容复制到本地文件中.

After this you should find out the ip address of the API server, and the Cluster CA certificate of the kubernetes cluster. This can be done by going to the kubernetes engine detail page on google cloud console. Copy the content of the certificate into a local file.

您现在可以使用承载令牌通过kubernetes python客户端进行身份验证，如下所示:

You can now use the bearer token to authenticate via the kubernetes python client, as follows:

from kubernetes import client

configuration = client.Configuration()
configuration.api_key["authorization"] = '<bearer_token>'
configuration.api_key_prefix['authorization'] = 'Bearer'
configuration.host = 'https://<ip_of_api_server>'
configuration.ssl_ca_cert = '<path_to_cluster_ca_certificate>'

v1 = client.CoreV1Api(client.ApiClient(configuration))

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