Knative第二部分-Knative Serving主要功能研究
目录
1. 灰度发布
修改helloworld-go.yaml，将"Go Sample v1"改成"Go Sample v2":
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: helloworld-go
namespace: example
spec:
template:
spec:
containers:
- image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8
env:
- name: TARGET
value: "Go Sample v2"
让上面的配置生效，查看service的变化：
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl apply -f helloworld-go.yaml
service.serving.knative.dev/helloworld-go configured
[root@sh-saas-k8stest-master-dev-01 knative]# kn service describe -n example helloworld-go
Name: helloworld-go
Namespace: example
Age: 14d
URL: http://helloworld-go.example.example.com
Revisions:
? helloworld-go-00002 (latest created) [2] (12s)
Image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8 (at 032b80)
100% @latest (helloworld-go-00001) [1] (14d)
Image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8 (at 032b80)
Replicas: 0/0
Conditions:
OK TYPE AGE REASON
?? Ready 12s
?? ConfigurationsReady 12s
++ RoutesReady 14d
[root@sh-saas-k8stest-master-dev-01 knative]# kn service describe -n example helloworld-go
Name: helloworld-go
Namespace: example
Age: 14d
URL: http://helloworld-go.example.example.com
Revisions:
100% @latest (helloworld-go-00002) [2] (24s)
Image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8 (at 032b80)
Replicas: 1/1
Conditions:
OK TYPE AGE REASON
++ Ready 11s
++ ConfigurationsReady 12s
++ RoutesReady 11s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m1.707s
user 0m0.003s
sys 0m0.002s
可以看到Knative Service会自动做滚动发布。
kservice会自动生成一个revision:helloworld-go-00002，最终将流量从revision helloworld-go-00001切换到helloworld-go-00002：
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl get revisions.serving.knative.dev -n example
NAME CONFIG NAME K8S SERVICE NAME GENERATION READY REASON ACTUAL REPLICAS DESIRED REPLICAS
helloworld-go-00001 helloworld-go helloworld-go-00001 1 True 0 0
helloworld-go-00002 helloworld-go helloworld-go-00002 2 True 0 0
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl get kservice helloworld-go -n example
NAME URL LATESTCREATED LATESTREADY READY REASON
helloworld-go http://helloworld-go.example.example.com helloworld-go-00002 helloworld-go-00002 True
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl get kservice helloworld-go -n example -o yaml
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
creationTimestamp: "2021-08-10T10:34:14Z"
name: helloworld-go
namespace: example
resourceVersion: "138660057"
selfLink: /apis/serving.knative.dev/v1/namespaces/example/services/helloworld-go
uid: 9522cb07-a15e-4995-a3e2-0389855e434d
spec:
template:
metadata:
creationTimestamp: null
spec:
containerConcurrency: 0
containers:
- env:
- name: TARGET
value: Go Sample v2
image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8
name: user-container
readinessProbe:
successThreshold: 1
tcpSocket:
port: 0
resources: {}
enableServiceLinks: false
timeoutSeconds: 300
traffic:
- latestRevision: true
percent: 100
status:
address:
url: http://helloworld-go.example.svc.cluster.local
conditions:
- lastTransitionTime: "2021-08-25T07:54:31Z"
status: "True"
type: ConfigurationsReady
- lastTransitionTime: "2021-08-25T07:54:32Z"
status: "True"
type: Ready
- lastTransitionTime: "2021-08-25T07:54:32Z"
status: "True"
type: RoutesReady
latestCreatedRevisionName: helloworld-go-00002
latestReadyRevisionName: helloworld-go-00002
observedGeneration: 2
traffic:
- latestRevision: true
percent: 100
revisionName: helloworld-go-00002
url: http://helloworld-go.example.example.com
1.1 按流量比例灰度发布
修改helloworld-go.yaml：
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: helloworld-go
namespace: example
spec:
template:
spec:
containers:
- image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8
env:
- name: TARGET
value: "Go Sample v2"
traffic:
- percent: 50
revisionName: helloworld-go-00001
- percent: 50
revisionName: helloworld-go-00002
测试：
[root@sh-saas-k8stest-master-dev-01 knative]# cat helloworld-go.yaml
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: helloworld-go
namespace: example
spec:
template:
spec:
containers:
- image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8
env:
- name: TARGET
value: "Go Sample v2"
traffic:
- percent: 50
revisionName: helloworld-go-00001
- percent: 50
revisionName: helloworld-go-00002
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m4.322s
user 0m0.002s
sys 0m0.002s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m0.015s
user 0m0.003s
sys 0m0.002s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v1!
real 0m20.436s
user 0m0.002s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v1!
real 0m0.007s
user 0m0.001s
sys 0m0.003s
1.2 基于Tag(子域名)金丝雀灰度发布
修改helloworld-go.yaml，增加tag：
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: helloworld-go
namespace: example
spec:
template:
spec:
containers:
- image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8
env:
- name: TARGET
value: "Go Sample v2"
traffic:
- percent: 50
revisionName: helloworld-go-00001
tag: a
- percent: 50
revisionName: helloworld-go-00002
tag: b
应用配置测试，可以发现正常的域名访问，还是基于流量比例来的：
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl apply -f ./helloworld-go.yaml
service.serving.knative.dev/helloworld-go configured
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v1!
real 0m15.506s
user 0m0.003s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m20.202s
user 0m0.002s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m0.007s
user 0m0.001s
sys 0m0.003s
除了上面的访问方式，还可以使用"tag名-域名"的访问来访问，这样就可以使用特定的域名来测试特定的版本。如：
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: a-helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v1!
real 0m0.006s
user 0m0.002s
sys 0m0.002s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: b-helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m0.007s
user 0m0.001s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: c-helloworld-go.example.example.com" http://10.248.132.176
real 0m0.018s
user 0m0.002s
sys 0m0.002s
1.3 基于http header金丝雀灰度发布
基于http header金丝雀灰度发布的需要Knative 0.16以上版本才支持，并且默认是关的，需要使用以下命令手动开启：
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl patch cm config-features -n knative-serving -p '{"data":{"tag-header-based-routing":"Enabled"}}'
configmap/config-features patched
helloworld-go.yaml跟上面一样，不需要做任何修改：
apiVersion: serving.knative.dev/v1
kind: Service
metadata:
name: helloworld-go
namespace: example
spec:
template:
spec:
containers:
- image: registry.cn-hangzhou.aliyuncs.com/knative-sample/helloworld-go:160e4dc8
env:
- name: TARGET
value: "Go Sample v2"
traffic:
- percent: 50
revisionName: helloworld-go-00001
tag: a
- percent: 50
revisionName: helloworld-go-00002
tag: b
我们下面直接测试就行：
通过下面的测试，我们发现基于tag-子域名的访问方式依然是可以使用的。
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: b-helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v2!
real 0m16.141s
user 0m0.002s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" http://10.248.132.176
Hello Go Sample v1!
real 0m20.507s
user 0m0.002s
sys 0m0.003s
通过下面的测试，我们发现可以通过http header头来访问，注意http header的名称为：Knative-Serving-Tag
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" -H "Knative-Serving-Tag:a" http://10.248.132.176
Hello Go Sample v1!
real 0m0.007s
user 0m0.002s
sys 0m0.002s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.example.example.com" -H "Knative-Serving-Tag:b" http://10.248.132.176
Hello Go Sample v2!
real 0m0.006s
user 0m0.002s
sys 0m0.002s
2. 配置自定义域名
3. 通过VirtualService来配置更多域名的访问
我们也可以通过编写下面的VirtualService，配置自己的域名及header等条件，实现灰度的功能或访问
3.1 使用rewrite模式
我们推荐使用VirtualService rewrite的功能来实现不同的域名，不同的headers及url等来实现不同的路由功能。 如下面的配置，我们通过header wid实现了一个灰度功能，并且使用了一个外部域名。
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: helloworld-go-rewrite-ingress
namespace: example
spec:
gateways:
- knative-serving/knative-ingress-gateway
#- knative-serving/knative-local-gateway
hosts:
- helloworld-go.weimobb.com
http:
- match:
- headers:
wid:
prefix: a
rewrite:
authority: a-helloworld-go.example.example.com
route:
- destination:
host: istio-ingressgateway.istio-system.svc.cluster.local
port:
number: 80
weight: 100
- match:
- headers:
wid:
prefix: b
rewrite:
authority: b-helloworld-go.example.example.com
route:
- destination:
host: istio-ingressgateway.istio-system.svc.cluster.local
port:
number: 80
weight: 100
我们看看测试效果，可以发现是符合预期的。
[root@sh-saas-k8stest-master-dev-01 knative]# kubectl apply -f ./helloworld-go-rewrite.yaml
virtualservice.networking.istio.io/helloworld-go-rewrite-ingress configured
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -i -L -H "Host: helloworld-go.weimobb.com" -H "wid: a" http://10.248.132.176
HTTP/1.1 200 OK
content-length: 20
content-type: text/plain; charset=utf-8
date: Thu, 02 Sep 2021 03:05:50 GMT
x-envoy-upstream-service-time: 10342
server: istio-envoy
Hello Go Sample v1!
real 0m10.364s
user 0m0.002s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -i -L -H "Host: helloworld-go.weimobb.com" -H "wid: b" http://10.248.132.176
HTTP/1.1 200 OK
content-length: 20
content-type: text/plain; charset=utf-8
date: Thu, 02 Sep 2021 03:06:07 GMT
x-envoy-upstream-service-time: 20031
server: istio-envoy
Hello Go Sample v2!
real 0m20.052s
user 0m0.001s
sys 0m0.004s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -i -L -H "Host: helloworld-go.weimobb.com" -H "wid: b" http://10.248.132.176
HTTP/1.1 200 OK
content-length: 20
content-type: text/plain; charset=utf-8
date: Thu, 02 Sep 2021 03:06:25 GMT
x-envoy-upstream-service-time: 3
server: istio-envoy
Hello Go Sample v2!
real 0m0.009s
user 0m0.001s
sys 0m0.004s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -i -L -H "Host: helloworld-go.weimobb.com" -H "wid: a" http://10.248.132.176
HTTP/1.1 200 OK
content-length: 20
content-type: text/plain; charset=utf-8
date: Thu, 02 Sep 2021 03:06:27 GMT
x-envoy-upstream-service-time: 2
server: istio-envoy
Hello Go Sample v1!
real 0m0.009s
user 0m0.004s
sys 0m0.002s
3.2 使用redirect模式
也可以通过redirect来做，如以下VirtualService配置：
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
name: helloworld-go-redirect-ingress
namespace: example
spec:
gateways:
- knative-serving/knative-ingress-gateway
- knative-serving/knative-local-gateway
hosts:
- helloworld-go.weimoba.com
http:
- match:
- authority:
prefix: helloworld-go.weimoba.com
redirect:
authority: a-helloworld-go.example.example.com
看看效果：
[root@sh-saas-k8stest-master-dev-01 knative]# echo "10.248.132.176 a-helloworld-go.example.example.com" >> /etc/hosts
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -i -L -H "Host: helloworld-go.weimoba.com" http://10.248.132.176
HTTP/1.1 301 Moved Permanently
location: http://a-helloworld-go.example.example.com/
date: Wed, 01 Sep 2021 10:30:23 GMT
server: istio-envoy
content-length: 0
HTTP/1.1 200 OK
content-length: 20
content-type: text/plain; charset=utf-8
date: Wed, 01 Sep 2021 10:30:23 GMT
x-envoy-upstream-service-time: 2
server: istio-envoy
Hello Go Sample v1!
real 0m0.019s
user 0m0.003s
sys 0m0.002s
3.3 使用直接到应用的模式
我们也可以通过配置自己的域名及header等条件直接转发到应用对应的服务上，以实现灰度的功能或访问：
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
name: helloworld-go-weimob-com-ingress
namespace: example
spec:
gateways:
- knative-serving/knative-ingress-gateway
- knative-serving/knative-local-gateway
hosts:
- helloworld-go.weimob.com
http:
- match:
- authority:
prefix: helloworld-go.weimob.com
gateways:
- knative-serving/knative-ingress-gateway
headers:
wid:
exact: a
retries: {}
route:
- destination:
host: helloworld-go-00001.example.svc.cluster.local
port:
number: 80
headers:
request:
set:
Knative-Serving-Namespace: example
Knative-Serving-Revision: helloworld-go-00001
weight: 100
- match:
- authority:
prefix: helloworld-go.weimob.com
gateways:
- knative-serving/knative-ingress-gateway
headers:
wid:
exact: b
retries: {}
route:
- destination:
host: helloworld-go-00002.example.svc.cluster.local
port:
number: 80
headers:
request:
set:
Knative-Serving-Namespace: example
Knative-Serving-Revision: helloworld-go-00002
weight: 100
查看效果，可以看到是预期内的：
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.weimob.com" -H "wid:b" http://10.248.132.176
Hello Go Sample v2!
real 0m20.578s
user 0m0.004s
sys 0m0.002s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.weimob.com" -H "wid:a" http://10.248.132.176
Hello Go Sample v1!
real 0m4.722s
user 0m0.002s
sys 0m0.003s
[root@sh-saas-k8stest-master-dev-01 knative]# time curl -H "Host: helloworld-go.weimob.com" http://10.248.132.176
real 0m0.006s
user 0m0.002s
sys 0m0.003s
PS: 解释一下VirtualService中authority的意思，它是访问URI中//到/之间的部分。如URI为"http://helloworld-go.weimob.com:8080/aaa"，则http authority为helloworld-go.weimob.com:8080。
根据rfc3986规范的组成语法，URI 进行拆解如下：
foo://example.com:8042/over/there?name=ferret#nose
\_/ \______________/\_________/ \_________/ \__/
| | | | |
scheme authority path query fragment
| _____________________|__
/ \ / \
urn:example:animal:ferret:nose
参考：https://zhuanlan.zhihu.com/p/216488873
参考：https://github.com/knative/docs/blob/mkdocs/docs/serving/samples/knative-routing-go/routing-internal.yaml
