Istio 添加和删除 header ，但不覆盖

Question

我正在尝试使用 Istio 使用 VirtualServices 添加、覆盖和删除 header 。向请求添加 header 并从响应中删除 header 效果很好，但不会覆盖请求中的 header 。

因此，根据 Istio 文档， header 操作如下:

这是我的VirtualService:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: server-vs
spec:
  hosts:
  - server.istio.svc.cluster.local
  http:
  - headers:
      request:
        set:
          test: "true"
        add:
          added: "header"
    route:
    - destination:
        host: server.istio.svc.cluster.local
        subset: apache
      weight: 90
    - destination:
        host: server.istio.svc.cluster.local
        subset: nginx
      headers:
        response:
          remove:
          - foo
      weight: 10

专注于设置 header ，这是我的理解。 Istio 将识别带有 test 键的 header ，并将用 true 覆盖该值。因此，如果我使用 -H "test: hello" 参数来 curl 我的服务，我应该在请求中看到 test: true 。

现在，我已在后端 pod 中安装了 tcpdump，并且可以看到 added: header。我还可以看到 foo: bar 已被删除(我的 nginx 服务器正在返回 foo: bar 以及响应)，但我看不到 test : true header 。我对 Istio header 操作的理解是否正确？

来自测试:

请求

/ # curl -H "test: hello" server
<h1>THIS IS AN ISTIO DEMO</h1>/ # 

回应

15:47:27.387891 IP 192.168.49.58.39652 > 192.168.113.134.80: Flags [S], seq 2810811797, win 28000, options [mss 1400,sackOK,TS val 1900372734 ecr 0,nop,wscale 7], length 0
E..<d.@.>.....1:..q....P..........m`
3.....x...
qEb.........
15:47:27.388130 IP 192.168.49.58.39652 > 192.168.113.134.80: Flags [.], ack 2093848160, win 219, options [nop,nop,TS val 1900372735 ecr 3950379544], length 0
E..4d.@.>.....1:..q....P....|..`.....z.....
qEb..v..
15:47:27.388202 IP 192.168.49.58.39652 > 192.168.113.134.80: Flags [P.], seq 2810811798:2810812507, ack 2093848160, win 219, options [nop,nop,TS val 1900372735 ecr 3950379544], length 709: HTTP: GET / HTTP/1.1
E...d.@.>.....1:..q....P....|..`....S&.....
qEb..v..GET / HTTP/1.1
host: server
user-agent: curl/7.59.0
accept: */*
test: hello                  <-HERE IS THE HEADER THAT SUPPOSED TO BE OVERWRITTEN
x-forwarded-proto: http
x-request-id: 05ff2bb6-8810-9411-8a3b-7456066e1d16
x-envoy-decorator-operation: server-vs:80/*
x-istio-attributes: CjwKGGRlc3RpbmF0aW9uLnNlcnZpY2UuaG9zdBIgEh5zZXJ2ZXIuaXN0aW8uc3ZjLmNsdXN0ZXIubG9jYWwKOgoXZGVzdGluYXRpb24uc2VydmljZS51aWQSHxIdaXN0aW86Ly9pc3Rpby9zZXJ2aWNlcy9zZXJ2ZXIKJAoYZGVzdGluYXRpb24uc2VydmljZS5uYW1lEggSBnNlcnZlcgooCh1kZXN0aW5hdGlvbi5zZXJ2aWNlLm5hbWVzcGFjZRIHEgVpc3Rpbwo6Cgpzb3VyY2UudWlkEiwSKmt1YmVybmV0ZXM6Ly9jdXJsZXItNzU1Y2M3Y2ZmZi14dmxiMi5pc3Rpbw==
x-b3-traceid: 741c90fab1ca5e23802399916451563e
x-b3-spanid: 802399916451563e
x-b3-sampled: 1
added: header                <- HERE IS THE ADDED HEADER
content-length: 0


15:47:27.390857 IP 192.168.49.58.39652 > 192.168.113.134.80: Flags [.], ack 2093848436, win 228, options [nop,nop,TS val 1900372737 ecr 3950379547], length 0
E..4d.@.>.....1:..q....P...[|..t...........
qEc..v..

但我期待看到test: true

Answer 1

一个愚蠢的事情解决了这个问题。看起来如果我在 yaml 文件中先定义 set 然后 add，它就不起作用，但如果我用 backwords 定义它，它就起作用。我猜这是一个错误。因此以下 yaml 有效:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: server-vs
spec:
  hosts:
  - server.istio.svc.cluster.local
  http:
  - headers:
      request:
        add:                    <- add goes first
          added: "header"
        set:                    <- set goes second
          test: "true"
    route:
    - destination:
        host: server.istio.svc.cluster.local
        subset: apache
      weight: 90
    - destination:
        host: server.istio.svc.cluster.local
        subset: nginx
      headers:
        response:
          remove:
          - foo
      weight: 10