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What you don't know about traifik

2022-06-24 01:24:00 【Luga Lee】

In the previous post , We briefly introduced about Traefik Related concepts and component principle mechanism , For details, please refer to ： Why choose Traefik Ingress ？

As an innovative edge router , signify Traefik It is the guardian of the whole application platform , Intercept and route every access request ： Based on the set logic and rules , To determine which services handle the corresponding request . About Traefik Model portrait of , For details, please refer to the following ：

traefik Topology

Of course , In addition to the service proxy characteristics , Traefik Also have “ Service discovery ” Functional mechanism , It dynamically detects back-end service status information and updates routing rules in real time , So as to achieve the effect of service governance .

We use Docker Provider The scene serves as a reference model for Traefik A brief analysis of Ecology , So that we can understand Traefik Related features .

In the following scenario , We are based on the latest version of Traefik v2.5.2 Image as an example , Deploy and run related instances , The details are as follows ：

[[email protected] ~] % vi docker-compose.yaml 
version: '3'
services:
  reverse-proxy:
    image: traefik:latest
    #  Turn on  web UI  also  Traefik  monitor  Docker
    command: --api.insecure=true --providers.docker
    ports:
      # HTTP  port 
      - "80:80"
      # Web UI  port ( adopt  --api.insecure=true  Enable )
      - "8080:8080"
    volumes:
      # Traefik  monitor  Docker  event 
      - /var/run/docker.sock:/var/run/docker.sock

then , We run this instance , As follows ：

[[email protected] ~] % docker-compose up -d reverse-proxy

[[email protected] ~] %  curl -i http://192.168.56.114:8080/api/rawdata?jsonHTTP/1.1 200 OKContent-Type: application/jsonDate: Thu, 09 Sep 2021 02:05:08 GMTContent-Length: 1361
HTTP/1.1 200 OK
Content-Type: application/json
Date: Thu, 09 Sep 2021 02:05:08 GMT
Content-Length: 1361

{"routers":{"[email protected]":{"entryPoints":["traefik"],"service":"[email protected]","rule":"PathPrefix(`/api`)","priority":2147483646,"status":"enabled","using":["traefik"]},"[email protected]":{"entryPoints":["traefik"],"middlewares":["[email protected]","[email protected]"],"service":"[email protected]","rule":"PathPrefix(`/`)","priority":2147483645,"status":"enabled","using":["traefik"]},"[email protected]":{"entryPoints":["http"],"service":"reverse-proxy-traefik","rule":"Host(`reverse-proxy-traefik`)","status":"enabled","using":["http"]}},"middlewares":{"[email protected]":{"redirectRegex":{"regex":"^(http:\\/\\/(\\[[\\w:.]+\\]|[\\w\\._-]+)(:\\d+)?)\\/$","replacement":"${1}/dashboard/","permanent":true},"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"stripPrefix":{"prefixes":["/dashboard/","/dashboard"]},"status":"enabled","usedBy":["[email protected]"]}},"services":{"[email protected]":{"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"status":"enabled"},"[email protected]":{"loadBalancer":{"servers":[{"url":"http://172.20.0.2:80"}],"passHostHeader":true},"status":"enabled","usedBy":["[email protected]"],"serverStatus":{"http://172.20.0.2:80":"UP"}}}}

here , We can also access... Through the browser http://192.168.56.114:8080/api/rawdata Interface to view Traefik Of API Raw data .

Next , We deploy a Demo service , be based on Traefik Create a route , The details are as follows ：

version: '3'

services:
  reverse-proxy:
    #  Official  Traefik 2.0 Docker  Mirror image 
    image: traefik:latest
    #  Turn on  web UI  And tell  Traefik  monitor  Docker
    command: --api.insecure=true --providers.docker
    ports:
      # HTTP  port 
      - "80:80"
      # Web UI  port ( adopt  --api.insecure=true  Enable )
      - "8080:8080"
    volumes:
      #  such  Traefik  Can monitor  Docker  event 
      - /var/run/docker.sock:/var/run/docker.sock

  whoami:
    #  One passes  API  Expose it  IP  Address container 
    image: containous/whoami
    labels:
      - "traefik.http.routers.whoami.rule=Host(`whoami.docker.localhost`)"

Based on the above Yaml In file , We defined A name is whoami ordinary web service , This service will print information about the deployed machine （IP Address 、 Host and so on ）. Then we use the following command to start whoami service , Specifically ：

[[email protected] ~] % docker-compose up -d whoami

here , We ask again Api Interface , The results are shown below ：

[[email protected] ~] % curl -i http://192.168.56.114:8080/api/rawdata?jsonHTTP/1.1 200 OKContent-Type: application/jsonDate: Thu, 09 Sep 2021 02:09:25 GMTContent-Length: 1705
HTTP/1.1 200 OK
Content-Type: application/json
Date: Thu, 09 Sep 2021 02:09:25 GMT
Content-Length: 1705

{"routers":{"[email protected]":{"entryPoints":["traefik"],"service":"[email protected]","rule":"PathPrefix(`/api`)","priority":2147483646,"status":"enabled","using":["traefik"]},"[email protected]":{"entryPoints":["traefik"],"middlewares":["[email protected]","[email protected]"],"service":"[email protected]","rule":"PathPrefix(`/`)","priority":2147483645,"status":"enabled","using":["traefik"]},"[email protected]":{"entryPoints":["http"],"service":"reverse-proxy-traefik","rule":"Host(`reverse-proxy-traefik`)","status":"enabled","using":["http"]},"[email protected]":{"entryPoints":["http"],"service":"whoami-traefik","rule":"Host(`whoami.docker.localhost`)","status":"enabled","using":["http"]}},"middlewares":{"[email protected]":{"redirectRegex":{"regex":"^(http:\\/\\/(\\[[\\w:.]+\\]|[\\w\\._-]+)(:\\d+)?)\\/$","replacement":"${1}/dashboard/","permanent":true},"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"stripPrefix":{"prefixes":["/dashboard/","/dashboard"]},"status":"enabled","usedBy":["[email protected]"]}},"services":{"[email protected]":{"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"status":"enabled"},"[email protected]":{"loadBalancer":{"servers":[{"url":"http://172.20.0.2:80"}],"passHostHeader":true},"status":"enabled","usedBy":["[email protected]"],"serverStatus":{"http://172.20.0.2:80":"UP"}},"[email protected]":{"loadBalancer":{"servers":[{"url":"http://172.20.0.3:80"}],"passHostHeader":true},"status":"enabled","usedBy":["[email protected]"],"serverStatus":{"http://172.20.0.3:80":"UP"}}}}

By looking at /api/rawdata The data returned by the interface , We found that Traefik The new container has been automatically detected and the corresponding configuration has been updated . I'm going to introduce Traefik When , We said , When Traefik When a new service is detected , It will automatically create the corresponding route , Then we can access the corresponding route . here , We use Curl Tools to verify , The details are as follows ：

[[email protected] ~] % curl -H Host:whoami.docker.localhost http://127.0.0.1
Hostname: d1078dbb0332
IP: 127.0.0.1
IP: 172.20.0.3
RemoteAddr: 172.20.0.2:37580
GET / HTTP/1.1
Host: whoami.docker.localhost
User-Agent: curl/7.29.0
Accept: */*
Accept-Encoding: gzip
X-Forwarded-For: 172.20.0.1
X-Forwarded-Host: whoami.docker.localhost
X-Forwarded-Port: 80
X-Forwarded-Proto: http
X-Forwarded-Server: 814dfa472b98
X-Real-Ip: 172.20.0.1

Next , We are right. whoami Service expansion , To verify Traefik Load balancing function of , The specific operation is shown below ：

[[email protected] ~] % docker-compose up -d --scale whoami=4
traefik_reverse-proxy_1 is up-to-date
Creating traefik_whoami_2 ... done
Creating traefik_whoami_3 ... done
Creating traefik_whoami_4 ... done

here , Let's take a look at the container status of our current service after the expansion , As shown below ：

[[email protected] ~] % docker-compose ps         
        Name                        Command               State                                     Ports                                   
---------------------------------------------------------------------------------------------------------------------------------------------
traefik_reverse-proxy_1   /entrypoint.sh --api.insec ...   Up      0.0.0.0:80->80/tcp,:::80->80/tcp, 0.0.0.0:8080->8080/tcp,:::8080->8080/tcp
traefik_whoami_1          /whoami                          Up      80/tcp                                                                    
traefik_whoami_2          /whoami                          Up      80/tcp                                                                    
traefik_whoami_3          /whoami                          Up      80/tcp                                                                    
traefik_whoami_4          /whoami                          Up      80/tc

[[email protected] ~] % curl -i http://192.168.56.114:8080/api/rawdata?json 
HTTP/1.1 200 OK
Content-Type: application/json
Date: Thu, 09 Sep 2021 02:28:35 GMT
Content-Length: 1882

{"routers":{"[email protected]":{"entryPoints":["traefik"],"service":"[email protected]","rule":"PathPrefix(`/api`)","priority":2147483646,"status":"enabled","using":["traefik"]},"[email protected]":{"entryPoints":["traefik"],"middlewares":["[email protected]","[email protected]"],"service":"[email protected]","rule":"PathPrefix(`/`)","priority":2147483645,"status":"enabled","using":["traefik"]},"[email protected]":{"entryPoints":["http"],"service":"reverse-proxy-traefik","rule":"Host(`reverse-proxy-traefik`)","status":"enabled","using":["http"]},"[email protected]":{"entryPoints":["http"],"service":"whoami-traefik","rule":"Host(`whoami.docker.localhost`)","status":"enabled","using":["http"]}},"middlewares":{"[email protected]":{"redirectRegex":{"regex":"^(http:\\/\\/(\\[[\\w:.]+\\]|[\\w\\._-]+)(:\\d+)?)\\/$","replacement":"${1}/dashboard/","permanent":true},"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"stripPrefix":{"prefixes":["/dashboard/","/dashboard"]},"status":"enabled","usedBy":["[email protected]"]}},"services":{"[email protected]":{"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"status":"enabled","usedBy":["[email protected]"]},"[email protected]":{"status":"enabled"},"[email protected]":{"loadBalancer":{"servers":[{"url":"http://172.20.0.2:80"}],"passHostHeader":true},"status":"enabled","usedBy":["[email protected]"],"serverStatus":{"http://172.20.0.2:80":"UP"}},"[email protected]":{"loadBalancer":{"servers":[{"url":"http://172.20.0.4:80"},{"url":"http://172.20.0.5:80"},{"url":"http://172.20.0.3:80"},{"url":"http://172.20.0.6:80"}],"passHostHeader":true},"status":"enabled","usedBy":["[email protected]"],"serverStatus":{"http://172.20.0.3:80":"UP","http://172.20.0.4:80":"UP","http://172.20.0.5:80":"UP","http://172.20.0.6:80":"UP"}}}}

here , We request 4 Time , To see Traefik Load balancing between four instances , The specific order is as follows ：

[[email protected] ~] % curl -H Host:whoami.docker.localhost http://127.0.0.1
#  for the first time 
Hostname: 50f70b1ccace
IP: 127.0.0.1
IP: 172.20.0.4
RemoteAddr: 172.20.0.2:40000
...
#  The second time 
Hostname: 8c2204231f98
IP: 127.0.0.1
IP: 172.20.0.5
RemoteAddr: 172.20.0.2:39660
...
#  third time 
Hostname: d1078dbb0332
IP: 127.0.0.1
IP: 172.20.0.3
RemoteAddr: 172.20.0.2:37600
...
#  The fourth time 
Hostname: f1cf5b632fde
IP: 127.0.0.1
IP: 172.20.0.6
RemoteAddr: 172.20.0.2:50384
...

Based on this , We go through http://192.168.56.114:8080/dashboard/#/ visit Traefik Web UI To observe different routing requests 、 service 、 Middleware and other related information . The details are as follows ：

traefik Interface

On the whole front page , We can see Traefik Requests for different protocols supported 、 Service type , involve HTTP、TCP as well as UDP etc. . meanwhile , Show different types of Providers Information , involve Docker、K8S And other relevant information . be based on HTTP agreement , You can see the 4 Routing rules ,5 A service and 2 A custom middleware . With Middlewares For example , We click based on HTTP Agreed “Middlewares ” Of the forum “Explore” link , You can see the link topology call chain formed by the currently deployed applications , The details are as follows ：

traefik middleware

in the light of Traefik Middlewares Custom development practices for , If you are interested , Refer to the previous article ：Traefik Middleware Plug in practice , So that everyone can understand Traefik The rich functions of .

Custom renewal for certificates , It's also Traefik One of the powerful functions of component , Based on this , We will be based on HTTP and DNS Two aspects are briefly described .

Based on the above scenario , Its brief activity flow is analyzed as ：

Traefik Use ACME（ A protocol （ Precisely agreed means of communication ）, Used to negotiate from LE Certificate . It is Traefik Part of ） towards LE（Let's Encrypt, A service that provides free certificates ） Request a certificate for a specific domain , Such as ,example.com.LE Answer with some randomly generated text ,Traefik Put this text in a specific location on the server .LE Then ask DNS Internet The server , for example .com, The server points to a IP Address .LE Through the port 80/443 View the... Of the file containing the random text IP Address .

If there is , So this proves that the person requesting the certificate controls both the server and the domain , Because it shows the right DNS Control of records . Certificate issued , Valid for 3 Months , The surplus is not enough 30 days ,Traefik Will automatically attempt to renew .

be based on HttpChallenge The advantage of is the ability to obtain wildcard certificates . These are validation of all subdomains *.example.com In addition , There is no need to open any ports . The related file configurations are as follows ：

## STATIC CONFIGURATION
log:
  level: INFO

api:
  insecure: true
  dashboard: true

entryPoints:
  web:
    address: ":80"
  websecure:
    address: ":443"

providers:
  docker:
    endpoint: "unix:///var/run/docker.sock"
    exposedByDefault: false

certificatesResolvers:
  lets-encr:
    acme:
      #caServer: https://acme-staging-v02.api.letsencrypt.org/directory
      storage: acme.json
      email: [email protected]
      httpChallenge:
        entryPoint: web

Based on this scenario ,Traefik Use ACME towards LE Request a certificate for a specific domain , Such as example.com.LE Answer some randomly generated text ,Traefik As a new DNS TXT Record . then ,LE Check example.com DNS Record to see if the text exists .

If it exists , So this proves that the person requesting the certificate controls the domain , The certificate is valid for 3 Months .Traefik Will be less than... In the remaining time 30 Day time automatically tries to renew .

Comparison based on HttpChallenge ,Traefik Need to be able to DNS Records are automatically updated , So any management DNS People on the site support this . That's why you use Cloudflare. The related file configurations are as follows ：

## STATIC CONFIGURATION
log:
  level: INFO

api:
  insecure: true
  dashboard: true

entryPoints:
  web:
    address: ":80"
  websecure:
    address: ":443"

providers:
  docker:
    endpoint: "unix:///var/run/docker.sock"
    exposedByDefault: false

certificatesResolvers:
  lets-encr:
    acme:
      #caServer: https://acme-staging-v02.api.letsencrypt.org/directory
      storage: acme.json
      email: [email protected]
      httpChallenge:
        entryPoint: web

In addition to the above characteristics , stay Traefik V2.3.x And in subsequent versions , Introduced a range of new features , Include Traefik Plug in system 、 And Traefik Pilot Integration of 、 Yes Amazon ECS Support, etc , Make Traefik Ecological components are becoming more and more functional , More and more application scenarios .

traefik pilot

In addition to the examples shown above 、 The alarm 、 In addition to the monitoring information function ,Traefik Pilot It also supports customization “ plug-in unit ” Development function , It provides a wealth of plug-in types , Adaptive assembly can be carried out in combination with actual business scenarios , The details are as follows ：

traefik pilot

in summary , As a cloud native edge router ,Traefik The function has been able to meet most business scenarios , meanwhile , It has also been applied in many industries . Maybe , In the next version , We will usher in a stronger Traefik ecology , Including the latest launch of the Google team Kubernetes Service API Support for , And for Traefik Mesh Chinese support mTLS The function of . In addition to the above , Other potential features will emerge as the market changes , Last , Let's wait and see ～

# Reference material