版本優先級
在 K8s 裡面有 preferred version，會選優先值最高的來做為預設值
規則
"^v([\\d]+)(?:(alpha|beta)([\\d]+))?$"
v{主版本}alpha|beta{副版本}
只有 v 開頭的穩定版(GA)最先優先，主要版本大的優先度最高。
再來是 beta 和 alpha
第三個比較 beta alpha 下的副版本
最後其他的 case 就是按照字母排序 strings.Compare (lexicographically)
參考這個範例可以更容易理解
- v10 // GA(General availability) 10
- v2 // GA 2
- v1 // GA 1
- v11beta2 // GA 11 + beta 2
- v10beta3 // GA 10 + beta 3
- v3beta1 // GA 3 + beta 1
- v12alpha1 // GA 12 + alpha 1
- v11alpha2 // GA 11 + alpha 2
- foo1 // 用字典順序排
- foo10 // 用字典順序排
APIGroup version
我們有一個 group 叫做 group.name，可以看到他會優先採用 v2
kc proxy & curl localhost:8001/apis/group.name
{
"kind": "APIGroup",
"apiVersion": "v1",
"name": "group.name",
"versions": [
{
"groupVersion": "group.name/v2",
"version": "v2"
},
{
"groupVersion": "group.name/v1",
"version": "v1"
}
],
"preferredVersion": {
"groupVersion": "group.name/v2",
"version": "v2"
}
}
會直接影響到 kubectl 的結果，直接 get 會拿到 v2
我們的 group.name 底下有 kind Cat
$ kc get cats my-cat -oyaml
apiVersion: group.name/v2
kind: Cat
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"group.name/v1","kind":"Cat","metadata":{"annotations":{},"name":"my-cat","namespace":"default"},"spec":{"age":18,"color":"#009920"}}
creationTimestamp: "2022-07-11T17:35:17Z"
generation: 1
name: my-cat
namespace: default
resourceVersion: "5111716"
uid: 388993d7-2075-406d-9668-4baec92d1562
spec:
color: '#009920'
不過我們也可以指定 kind.version.group 去拿指定版本的資源
$ kc get cats.v1.group.name my-cat -oyaml
apiVersion: group.name/v1
kind: Cat
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"group.name/v1","kind":"Cat","metadata":{"annotations":{},"name":"my-cat","namespace":"default"},"spec":{"age":18,"color":"#009920"}}
creationTimestamp: "2022-07-11T17:35:17Z"
generation: 1
name: my-cat
namespace: default
resourceVersion: "5111716"
uid: 388993d7-2075-406d-9668-4baec92d1562
spec:
age: 18
color: '#009920'
另外，kubectl 有 cache 我們也可以去欺騙他（？
vim ~/.kube/cache/discovery/127.0.0.1_58359/servergroups.json
{
"name": "group.name",
"versions": [
{
"groupVersion": "group.name/v2",
"version": "v2"
},
{
"groupVersion": "group.name/v1",
"version": "v1"
}
],
"preferredVersion": {
- "groupVersion": "group.name/v2",
- "version": "v2"
+ "groupVersion": "group.name/v1",
+ "version": "v1"
}
},
然後再去 kubectl get 不指定版本
kc get cats my-cat -oyaml
apiVersion: group.name/v1
kind: Cat
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"group.name/v1","kind":"Cat","metadata":{"annotations":{},"name":"my-cat","namespace":"default"},"spec":{"age":18,"color":"#009920"}}
creationTimestamp: "2022-07-11T17:35:17Z"
generation: 1
name: my-cat
namespace: default
resourceVersion: "5111716"
uid: 388993d7-2075-406d-9668-4baec92d1562
spec:
age: 18
color: '#009920'
看一眼 etcd 來證明
sudo apt update
sudo apt install etcd-client
alias ec='ETCDCTL_API=3 etcdctl --cacert=/etc/kubernetes/pki/etcd/ca.crt --cert=/etc/kubernetes/pki/etcd/peer.crt --key=/etc/kubernetes/pki/etcd/peer.key'
ec get / --prefix --keys-only
etcd 的 key 規則類似 /registry/{group}/{kind}/{namespace}/{name}
# 用 json 格式拿出來看，發現是 Base64
$ ec get /registry/unagi.xiao.xiao/unagilives/unagi-system/unagilive-sample -wjson | jq .
# 解開來看到原味內容
$ ec get /registry/unagi.xiao.xiao/unagilives/unagi-system/unagilive-sample -wjson | jq -r .kvs[0].value | base64 -d | jq '.metadata.name, .spec, .status'
"unagilive-sample"
{
"color": "meow"
}
{
"reconciledTime": "2022-07-07T09:14:56Z",
"status": "Reconciled"
}