如何在 K8S 集群范围使用 imagePullSecret?
在这篇文章中,我将向你展示如何在 Kubernetes 中使用 imagePullSecrets。
imagePullSecrets 简介
Kubernetes 在每个 Pod 或每个 Namespace 的基础上使用 imagePullSecrets 对私有容器注册表进行身份验证。要做到这一点,你需要创建一个秘密与凭据:
{% note warning %}
⚠️ 警告:
现在随着公共镜像仓库(如:docker.io 等)开始对匿名用户进行限流,配置公共仓库的身份认证也变得有必要。
{% endnote %}
kubectl create secret docker-registry image-pull-secret \
-n <your-namespace> \
--docker-server=<your-registry-server> \
--docker-username=<your-name> \
--docker-password=<your-password> \
--docker-email=<your-email>
例如配置 docker.io 的 pull secret:
kubectl create secret docker-registry image-pull-secret-src \
-n imagepullsecret-patcher \
--docker-server=docker.io \
--docker-username=caseycui \
--docker-password=c874d654-xxxx-40c6-xxxx-xxxxxxxx89c2 \
--docker-email=cuikaidong@foxmail.com
{% note info %}
ℹ️ 信息:
如果 docker.io 启用了「2 阶段认证」,可能需要创建 Access Token(对应上面的 docker-password
,创建链接在这里:账号 -> 安全
{% endnote %}
现在我们可以在一个 pod 中使用这个 secret 来下载 docker 镜像:
apiVersion: v1
kind: Pod
metadata:
name: busybox
namespace: private-registry-test
spec:
containers:
- name: my-app
image: my-private-registry.infra/busybox:v1
imagePullSecrets:
- name: image-pull-secret
另一种方法是将它添加到命名空间的默认 ServiceAccount 中:
kubectl patch serviceaccount default \
-p "{\"imagePullSecrets\": [{\"name\": \"image-pull-secret\"}]}" \
-n <your-namespace>
在 K8S 集群范围使用 imagePullSecrets
我找到了一个叫做 imagepullsecret-patch
的工具,它可以在你所有的命名空间上做这个:
wget https://raw.githubusercontent.com/titansoft-pte-ltd/imagepullsecret-patcher/185aec934bd01fa9b6ade2c44624e5f2023e2784/deploy-example/kubernetes-manifest/1_rbac.yaml
wget https://raw.githubusercontent.com/titansoft-pte-ltd/imagepullsecret-patcher/master/deploy-example/kubernetes-manifest/2_deployment.yaml
kubectl create ns imagepullsecret-patcher
编辑下载的文件,一般需要修改image-pull-secret-src
的内容,这个 pull secret 就会应用到 K8S 集群范围。
nano 1_rbac.yaml
nano 2_deployment.yaml
kubectl apply -f 1_rbac.yaml
kubectl apply -f 2_deployment.yaml
这里背后创建的资源有:
- NameSpace
- RBAC 权限相关:
imagepullsecret-patcher
ServiceAccountimagepullsecret-patcher
ClusterRole,具有对 service account 和 secret 的所有权限imagepullsecret-patcher
ClusterRoleBinding,为imagepullsecret-patcher
ServiceAccount 赋予imagepullsecret-patcher
ClusterRole 的权限。
- 全局 pull secret
image-pull-secret-src
,里面是你的 K8S 全局包含的所有的镜像库地址和认证信息。 - Deployment
imagepullsecret-patcher
,指定 ServiceAccount 是imagepullsecret-patcher
就有了操作 service account 和 secret 的所有权限,并将上面的 secret 挂载到 Deployment pod 内。
可以包含多个镜像库地址和认证信息,如:
{
"auths": {
"docker.io": {
"username": "caseycui",
"password": "c874xxxxxxxxxxxxxxxx1f89c2",
"email": "cuikaidong@foxmail.com",
"auth": "Y2FzxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxWMy"
},
"quay.io": {
"auth": "ZWFzdxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxlXWmpNPQ==",
"email": ""
}
}
}
base64 编码后写到 secret 的 .dockerconfigjson
字段即可:
apiVersion: v1
kind: Secret
metadata:
name: image-pull-secret-src
namespace: imagepullsecret-patcher
data:
.dockerconfigjson: >-
eyJhdXRocyI6eyJkb2NrZXIuaW8iOnsidXNlcm5hbWUiOiJjYXNleWN1aSIsInB.............................................IiwiZW1haWwiOiIifX19
type: kubernetes.io/dockerconfigjson
启动后的 pod 会在所有 NameSpace 下创建 image-pull-secret
secret(内容来自于image-pull-secret-src
) 并把它 patch 到 default
service account 及该 K8S 集群的所有 ServiceAccount 里,日志如下:
time="2022-01-12T16:07:30Z" level=info msg="Application started"
time="2022-01-12T16:07:30Z" level=info msg="[default] Created secret"
time="2022-01-12T16:07:30Z" level=info msg="[default] Patched imagePullSecrets to service account [default]"
time="2022-01-12T16:07:30Z" level=info msg="[kube-system] Created secret"
time="2022-01-12T16:07:31Z" level=info msg="[kube-system] Patched imagePullSecrets to service account [node-controller]"
...
time="2022-01-12T16:07:37Z" level=info msg="[kube-public] Created secret"
time="2022-01-12T16:07:37Z" level=info msg="[kube-public] Patched imagePullSecrets to service account [default]"
time="2022-01-12T16:07:38Z" level=info msg="[kube-node-lease] Created secret"
time="2022-01-12T16:07:38Z" level=info msg="[kube-node-lease] Patched imagePullSecrets to service account [default]"
time="2022-01-12T16:07:38Z" level=info msg="[prometheus] Created secret"
time="2022-01-12T16:07:39Z" level=info msg="[prometheus] Patched imagePullSecrets to service account [default]"
...
time="2022-01-12T16:07:41Z" level=info msg="[imagepullsecret-patcher] Created secret"
time="2022-01-12T16:07:41Z" level=info msg="[imagepullsecret-patcher] Patched imagePullSecrets to service account [default]"
time="2022-01-12T16:07:41Z" level=info msg="[imagepullsecret-patcher] Patched imagePullSecrets to service account [imagepullsecret-patcher]"
今后我们只需要更新 image-pull-secret-src
这一个即可了。👍️👍️👍️
Kyverno policy
Kyverno policy 可以实现同样的效果:
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
name: sync-secret
spec:
background: false
rules:
- name: sync-image-pull-secret
match:
resources:
kinds:
- Namespace
generate:
kind: Secret
name: image-pull-secret
namespace: "{{request.object.metadata.name}}"
synchronize: true
clone:
namespace: default
name: image-pull-secret
---
apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
name: mutate-imagepullsecret
spec:
rules:
- name: mutate-imagepullsecret
match:
resources:
kinds:
- Pod
mutate:
patchStrategicMerge:
spec:
imagePullSecrets:
- name: image-pull-secret ## imagePullSecret that you created with docker hub pro account
(containers):
- (image): "*" ## match all container images
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