云原生之旅 - 9）云原生时代网关的后起之秀Envoy Proxy 和基于Envoy 的 Emissary Ingress

时间：2022-11-07 09:09:01

前言

前一篇文章讲述了基于Nginx代理的Kuberenetes Ingress Nginx【云原生时代的网关 Ingress Nginx】这次给大家介绍下基于Envoy的 Emissary Ingress。

 

首先什么是Enovy？

Envoy 是由 Lyft 开源的高性能网络代理软件，后来捐赠给了 CNCF 基金会，已经毕业于CNCF。 相比于 Nginx、HAProxy 等经典代理软件，Envoy 具备丰富的可观察性和灵活的可扩展性，并且引入了基于 xDS API 的动态配置方案，Envoy 还提供了大量的开箱即用的 Filter 以满足各种场景下流量治理的需求。

Envoy 与 Nginx 代理的区别

  • Envoy 对 HTTP/2 的支持比 Nginx 更好，支持包括 upstream 和 downstream在内的双向通信，而 Nginx 只支持 downstream 的连接。
  • 高级负载均衡功能是免费的，Nginx 的高级负载均衡功能则需要商业版 Nginx Plus 支持。
  • Envoy 支持热更新，Nginx 配置更新之后需要 Reload。
  • Envoy 更贴近 Service Mesh 的使用习惯，Nginx 更贴近传统服务的使用习惯。

Envoy 有典型的两种工作模式。一种作为中心代理，代理集群的南北向流量，这种模式下，Envoy 一般就是负载均衡设备或者是 API 网关的基础数据面，比如 Ambassador 现在叫 Emissary，Gloo 都是新兴的开源的基于 Envoy 的开源网关。另一种模式，就是作为业务进程的 Sidecar，当有业务请求访问业务的时候，流量会被劫持到 Sidecar Envoy 当中，之后再被转发给业务进程，典型代表 Istio 和 Linkerd.

今天我们介绍的就是代理南北向流量的网关 Emissary Ingress（原名 Ambassador）。Emissary-ingress已经是CNCF的孵化项目，并且在去年被*服务网状项目Linkerd和Istio正式支持。如需集成参考文档。

 

关键词：基于Enovy的Emissary Ingress实践，Emissary Ingress入门，云原生网关Emissary Ingress，Emissary Ingress实践

 

为什么选择 Emissary Ingress

https://www.getambassador.io/docs/emissary/latest/about/alternatives/

https://www.getambassador.io/docs/emissary/latest/about/faq/#why-emissary-ingress

 

安装

使用Terraform Helm Provider

从 emissary-ingress 2.1开始, 它把 CRDs 从Helm Charts移除了, 现在首先需要手动 apply CRDs。

kubectl apply -f https://app.getambassador.io/yaml/emissary/3.2.0/emissary-crds.yaml

所以我做了一个Helm Charts 专门装下CRDs，否则无法全流程安装自动化。

如果不了解Helm Chart 请参考这篇文章【Kubernetes时代的包管理工具 Helm】入门。

resource "helm_release" "emissary_crds" {
     name             = "emissary-crds"
     create_namespace = true # create emissary default namespace `emissary-system`
     namespace        = local.emissary_ns
     chart            = "../common/helm/repos/emissary-crds-8.2.0.tgz"
}

CRDs是默认装在`emissary-system` namespace下面的，不建议修改namespace，如果要在不同的Namespace下装多个Emissary ingress， 是可以共用这个CRDs的。

下面这部分是官方chart
# Install Emissary-ingress from Chart Repository
resource "helm_release" "emissary_ingress" {
  name             = "emissary-ingress"
  repository       = "https://app.getambassador.io"
  chart            = "emissary-ingress"
  version          = local.chart_version
  create_namespace = true
  namespace        = local.emissary_ns

  values = [
    templatefile("${local.common_yaml_d}/emissary-ingress-template.yaml", local.emissary_ingress_map)
  ]

  depends_on = [
    helm_release.emissary_crds
  ]
}

最后一部分，也是自制 chart 专门负责config

# This is for install Host/Listener/Mapping/TLSContext from a local custom chart
# also can upload chart to a bucket or a public github for install from a url
# e.g. [Publish to a GCS bucket](https://github.com/hayorov/helm-gcs)
resource "helm_release" "emissary_config" {
  name      = "emissary-config"
  namespace = local.emissary_ns
  chart     = "../common/helm/repos/emissary-config-8.2.0.tgz"

  values = [
    templatefile("${local.common_yaml_d}/emissary-listeners-template.yaml", local.emissary_listeners_map),
    local.emissary_config_yaml
  ]

  depends_on = [
    helm_release.emissary_ingress
  ]
}

locals 变量

locals {

  project_id     = "global-sre-dev"
  cluster_name   = "sre-gke"
  cluster_region = "us-central1"
  emissary_ns    = "emissary"
  chart_version  = "8.2.0"
  common_yaml_d  = "../common/helm/yamls"
  ambassador_id  = "ambassador"

  emissary_ingress_map = {
    ambassadorID          = local.ambassador_id
    loadBalancerIP        = "35.232.98.249" # Prepare a Static IP first instead to use Ephemeral
    replicaCount          = 2
    minReplicas           = 2
    maxReplicas           = 3
    canaryEnabled         = false # set to true in Prod
    logLevel              = "error" # valid log levels are error, warn/warning, info, debug, and trace
    endpointEnable        = true
    endpointName          = "my-resolver"
    diagnosticsEnable     = false
    clusterRequestTimeout = 120000 # milliseconds
  }

  emissary_listeners_map = {
    ambassadorID          = local.ambassador_id
    listenersEnabled      = true # custom listeners
  }
}
locals.tf

config文件

locals {
  emissary_config_yaml = <<-EOT
    hosts:
    - name: my-host-dev
      spec:
        ambassador_id: 
        - ${local.ambassador_id}
        hostname: '*.wadexu.cloud'
        requestPolicy:
          insecure:
            action: Redirect
        tlsContext:
          name: my-tls-context
        tlsSecret:
          name: tls-secret
          namespace: secret
    mappings:
    - name: my-nginx-mapping
      spec:
        ambassador_id:
        - ${local.ambassador_id}
        hostname: dev.wadexu.cloud
        prefix: /
        service: my-nginx.nginx:80

    tlscontexts:
    - name: my-tls-context
      spec:
        ambassador_id: 
        - ${local.ambassador_id}
        hosts:
        - "*.wadexu.cloud"
        min_tls_version: v1.2
  EOT
}
config.tf

完整代码请参考 my repo

另外因为用的https，所以需要一个tls-secret 安装在secret ns下面
kubectl create secret -n secret tls tls-secret \
  --key ./xxx.key \
  --cert ./xxx.pem

Install from local， (Optional) 如果要学习自动化Terraform安装，请参考【部署Terrform基础设施代码的自动化利器 Atlantis】

cd terraform_helm_install/dev

terraform init
terraform plan 
terraform apply

Install result

% helm list -n emissary-system
NAME         	NAMESPACE      	REVISION	UPDATED                            	STATUS  	CHART              	APP VERSION
emissary-crds	emissary-system	1       	2022-10-20 10:09:30.72553 +0800 CST	deployed	emissary-crds-8.2.0	3.2.0         

% helm list -n emissary                             
NAME            	NAMESPACE	REVISION	UPDATED                             	STATUS  	CHART                 	APP VERSION
emissary-config 	emissary 	1       	2022-10-20 10:31:24.819555 +0800 CST	deployed	emissary-config-8.2.0 	3.2.0      
emissary-ingress	emissary 	1       	2022-10-20 10:29:33.705888 +0800 CST	deployed	emissary-ingress-8.2.0	3.2.0   

 

使用 Kustomize

参考我的 quick start

如果不了解 Kustomize， 请移步我这篇文章【不能错过的一款 Kubernetes 应用编排管理神器 Kustomize】

 

一个集群安装多个Emissary Ingress

我这个例子 This example 展示了 multiple Emissary deployed in one cluster.

在一个集群里安装多个 Emissary 一定要设置 ambassador_id 并且替换 ClusterRoleBinding name， 否则资源冲突。

  • emissary-ingress-init: CRDs will be installed.
  • emissary-ingress-public: An emissary-ingress with allow list = all (face to internet).
  • emissary-ingress-private: Another emissary-ingress with an allow list (restrict connection) installed in same cluster.

 

Test in local

# apply CRDs first
kustomize build emissary-ingress-init/sre-mgmt-dev > ~/init.yaml
kubectl apply -f ~/init.yaml

# deploy first public Emissary, this allow list = all, face to internet
kustomize build emissary-ingress-public/sre-mgmt-dev > ~/emissary_deploy1.yaml
kubectl apply -f ~/emissary_deploy1.yaml

# deploy second private Emissary with a restrict allow list to access
kustomize build emissary-ingress-private/sre-mgmt-dev > ~/emissary_deploy2.yaml
kubectl apply -f ~/emissary_deploy2.yaml

通过Terraform安装 Kustomize资源，请参考 my repo

如：

module "example_custom_manifests" {
  source  = "kbst.xyz/catalog/custom-manifests/kustomization"
  version = "0.3.0"

  configuration_base_key = "default"
  configuration = {
    default = {

      resources = [
        "${path.root}/../../infra/emissary-ingress-init/sre-mgmt-dev"
      ]

      common_labels = {
        "env" = "dev"
      }
    }
  }
}

 

Test

建一个nginx service 测试下

helm install my-nginx bitnami/nginx --set service.type="ClusterIP" -n nginx --create-namespace

curl

% curl https://dev.wadexu.cloud
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
html { color-scheme: light dark; }
body { width: 35em; margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif; }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>

 

FAQ

1. 这个error 代表 tls-secret 有问题，确保正确创建

error:1404B42E:SSL routines:ST_CONNECT:tlsv1 alert protocol version

 

2. Connection refused, 最大的可能是 Listeners 没有配置好。

curl: (7) Failed to connect to dev.wadexu.cloud port 443 after 255 ms: Connection refused

 

3. CRDs 没创建。

│ Error: unable to build kubernetes objects from release manifest: [resource mapping not found for name: "my-resolver" namespace: "emissary-system" from "": no matches for kind "KubernetesEndpointResolver" in version "getambassador.io/v2"
│ ensure CRDs are installed first, resource mapping not found for name: "ambassador" namespace: "emissary-system" from "": no matches for kind "Module" in version "getambassador.io/v2"
│ ensure CRDs are installed first]
注意: If helm provider > 2.7.0, plan will prompt this error. Workaround is apply CRDs first. `terraform apply -target helm_release.emissary_crds` 然后 apply 剩下的资源。
所以用helm provider <= 2.6.0一次性创建比较好。这个问题已经有人在github 提过issue了。
 
另外，TLSContext 里面的 secret_namespacing 不work，issue， 但不影响，我的例子把tls-secret放在kind: Host下面。
 
 
感谢阅读，如果您觉得本文的内容对您的学习有所帮助，您可以打赏和推荐，您的鼓励是我创作的动力。
 
 
 
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