kubectl
会使用$HOME/.kube
目录下的config
文件作为缺省的配置文件。我们可以使用kubectl config view
查看配置信息:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
|
$kubectl config view
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: DATA+OMITTED
server: https://172.18.100.90:6443
name: cluster-1
contexts:
- context:
cluster: cluster-1
user: cluster-1-admin
name: cluster-1-admin@cluster-1
current-context: cluster-1-admin@cluster-1
kind: Config
preferences: {}
users:
- name: cluster-1-admin
user:
client-certificate-data: REDACTED
client-key-data: REDACTED
|
可以看到,配置文件主要包含了clusters
,users
和contexts
三部分信息。context
是访问一个kubernetes
集群所需要的参数集合。每个context
有三个参数:
cluster
:要访问的集群信息
namespace
:用户工作的namespace
,缺省值为default
user
:连接集群的认证用户
缺省情况下,kubectl
会使用current-context
指定的context
作为当前的工作集群环境。不难想象,切换context
就可以切换到不同的kubernetes
集群。
在不了解context
的概念之前,想访问不同的集群,每次都要把集群对应的config
文件copy到$HOME/.kube
目录下,同时要记得使用kubectl cluster-info
确认当前访问的集群:
1
2
3
4
5
6
|
$kubectl cluster-info
Kubernetes master is running at https://172.18.100.90:6443
KubeDNS is running at https://172.18.100.90:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
|
在看了这篇文档后,才知道kubectl
可以切换context
来管理多个集群。如果你有多个集群的config
文件,可以在系统环境变量KUBECONFIG
中指定每个config
文件的路径,例如:
1
|
export KUBECONFIG=/home/mazhen/kube-config/config-cluster-1:/home/mazhen/kube-config/config-cluster-1
|
再使用kubectl config view
查看集群配置时,kubectl
会自动合并多个config
的信息:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
$ kubectl config view
apiVersion: v1
clusters:
- cluster:
certificate-authority-data: DATA+OMITTED
server: https://172.20.51.11:6443
name: cluster-2
- cluster:
certificate-authority-data: DATA+OMITTED
server: https://172.18.100.90:6443
name: cluster-1
contexts:
- context:
cluster: cluster-2
user: cluster-2-admin
name: cluster-2-admin@cluster-2
- context:
cluster: cluster-1
user: cluster-1-admin
name: cluster-1-admin@cluster-1
current-context: cluster-1-admin@cluster-1
kind: Config
preferences: {}
users:
- name: cluster-2-admin
user:
client-certificate-data: REDACTED
client-key-data: REDACTED
- name: cluster-1-admin
user:
client-certificate-data: REDACTED
client-key-data: REDACTED
|
可以看到,配置中包含了两个集群,两个用户,以及两个context
。我们可以使用kubectl config get-contexts
查看配置中所有的context
:
1
2
3
4
5
|
$ kubectl config get-contexts
CURRENT NAME CLUSTER AUTHINFO NAMESPACE
cluster-2-admin@cluster-2 cluster-2 cluster-2-admin
* cluster-1-admin@cluster-1 cluster-1 cluster-1-admin
|
星号*
标识了当前的工作集群。如果想访问另一个集群,使用kubectl config use-context
进行切换:
1
2
3
|
$ kubectl config use-context cluster-2-admin@cluster-2
Switched to context "cluster-2-admin@cluster-2".
|
我们可以再次确认切换的结果:
1
2
3
4
5
6
7
8
9
10
11
12
13
|
$ kubectl config get-contexts
CURRENT NAME CLUSTER AUTHINFO NAMESPACE
* cluster-2-admin@cluster-2 cluster-2 cluster-2-admin
cluster-1-admin@cluster-1 cluster-1 cluster-1-admin
$ kubectl cluster-info
Kubernetes master is running at https://172.20.51.11:6443
KubeDNS is running at https://172.20.51.11:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
kubernetes-dashboard is running at https://172.20.51.11:6443/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy
To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
|
看吧,kubectl
切换context
管理多集群是多么的方便。