Clever Geek Handbook

New HAProxy Data Plane API: Two Programming Examples

Use the HAProxy Data Plane API to dynamically control the load balancer configuration using HTTP commands.



Designing for high availability almost always means having a high level proxy / load balancer. A proxy server provides basic services such as:



  • detection and removal of faulty servers
  • connection queue
  • offloading TLS encryption
  • compression
  • caching


The challenge is to keep your configurations up to date, which is especially difficult as services move into containers and those containers become ephemeral. Available since HAProxy 2.0 you can use the new HAProxy Data Plane API (Translation: https://habr.com/en/post/508132/ ), which is a modern REST API.



The HAProxy Data Plane API complements the flexible HAProxy configuration language , which provides building blocks for defining simple and complex routing rules. It is also the perfect complement to the existing Runtime API , which allows you to start, stop, and skip server traffic, change server weight, and manage health checks.



The new Data Plane API gives you the ability to dynamically add and configure frontend, backend, and traffic routing logic. You can also use it to update logging endpoints and create SPOE filters. In fact, almost the entire load balancer can be configured using HTTP commands. In this article, you will learn how best to use it.



Configuration management



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, , . , . , TLS. , , .



HTTP API . Data Plane API . HAProxy Data Plane API HAProxy . , API API , .



Data Plane API Go config-parser client-native HAProxy Runtime API . HAProxy.



HAProxy



Data Plane API . , backend frontend, . API.



, GET /v1/services/haproxy/configuration/backends, backend, :



$ curl --get --user admin:mypassword \
    http://localhost:5555/v1/services/haproxy/configuration/backends


backend, endpoint POST. — . , .



endpoint /v1/services/haproxy/transactions . URL, . , POST, PUT DELETE, , HAProxy. , API, . , , , , . .



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       http://localhost:5555/v1/services/haproxy/transactions?version=1


JSON:



{"_version":5,"id":"9663c384-5052-4776-a968-abcef032aeef","status":"in_progress"}


endpoint /v1/services/haproxy/configuration/backends, , URL:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"name": "test_backend", "mode":"http", "balance": {"algorithm":"roundrobin"}, "httpchk": {"method": "HEAD", "uri": "/", "version": "HTTP/1.1"}}' \     
       http://localhost:5555/v1/services/haproxy/configuration/backends?transaction_id=9663c384-5052-4776-a968-abcef032aeef


endpoint /v1/services/haproxy/configuration/servers backend:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"name": "server1", "address": "127.0.0.1", "port": 8080, "check": "enabled", "maxconn": 30, "weight": 100}' \
       "http://localhost:5555/v1/services/haproxy/configuration/servers?backend=test_backend&transaction_id=9663c384-5052-4776-a968-abcef032aeef"


frontend endpoint /v1/services/haproxy/configuration/frontends :



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"name": "test_frontend", "mode": "http", "default_backend": "test_backend", "maxconn": 2000}' \
       http://localhost:5555/v1/services/haproxy/configuration/frontends?transaction_id=9663c384-5052-4776-a968-abcef032aeef


frontend bind . , endpoint /v1/services/haproxy/configuration/binds, :



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"name": "http", "address": "*", "port": 80}' \
       "http://localhost:5555/v1/services/haproxy/configuration/binds?frontend=test_frontend&transaction_id=9663c384-5052-4776-a968-abcef032aeef"


, , endpoint /v1/services/haproxy/transactions/[transaction ID] PUT, :



$ curl -X PUT --user admin:mypassword \
       -H "Content-Type: application/json" \
       http://localhost:5555/v1/services/haproxy/transactions/9663c384-5052-4776-a968-abcef032aeef


:



frontend test_frontend
    mode http
    maxconn 2000
    bind *:80 name http
    default_backend test_backend

backend test_backend
    mode http
    balance roundrobin
    option httpchk HEAD / HTTP/1.1
    server server1 127.0.0.1:8080 check maxconn 30 weight 100


.



Data Plane API OpenAPI, .



. . URL transaction_id , .





HAProxy Data Plane API. HTTP- . . ACL, Host example.com. , use_backend example_servers. http-request deny, URL /admin.php, IP- 192.168.50.20/24.



endpoint /v1/services/haproxy/transactions :



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \ 
       http://localhost:5555/v1/services/haproxy/transactions?version=2

{"_version":2,"id":"7d0d6737-655e-4489-92eb-6d29cdd69827","status":"in_progress"}


endpoint /v1/services/haproxy/configuration/backends , backend example_servers:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"name": "example_servers", "mode":"http", "balance": {"algorithm":"roundrobin"}}' \
       http://localhost:5555/v1/services/haproxy/configuration/backends?transaction_id=7d0d6737-655e-4489-92eb-6d29cdd69827


endpoint /v1/services/haproxy/configuration/servers server backend:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"name": "server1", "address": "127.0.0.1", "port": 8081, "check": "enabled", "maxconn": 30, "weight": 100}' \
       "http://localhost:5555/v1/services/haproxy/configuration/servers?backend=example_servers&transaction_id=7d0d6737-655e-4489-92eb-6d29cdd69827"


endpoint /v1/services/haproxy/configuration/acls, ACL is_example, , example.com:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"id": 0, "acl_name": "is_example", "criterion": "req.hdr(Host)", "value": "example.com"}' \
       "http://localhost:5555/v1/services/haproxy/configuration/acls?parent_type=frontend&parent_name=test_frontend&transaction_id=7d0d6737-655e-4489-92eb-6d29cdd69827"


/v1/services/haproxy/configuration/backend_switching_rules, use_backend, ACL is_example:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"id": 0, "cond": "if", "cond_test": "is_example", "name": "example_servers"}' \
       "http://localhost:5555/v1/services/haproxy/configuration/backend_switching_rules?frontend=test_frontend&transaction_id=7d0d6737-655e-4489-92eb-6d29cdd69827"


endpoint /v1/services/haproxy/configuration/http_request_rules, http-request deny, , /admin.php, IP- 192.168.50.20/24:



$ curl -X POST --user admin:mypassword \
       -H "Content-Type: application/json" \
       -d '{"id": 0, "cond": "if", "cond_test": "{ path /admin.php } !{ src 192.168.50.20/24 }", "type": "deny"}' \
       "http://localhost:5555/v1/services/haproxy/configuration/http_request_rules?parent_type=frontend&parent_name=test_frontend&transaction_id=7d0d6737-655e-4489-92eb-6d29cdd69827"


, :



$ curl -X PUT --user admin:mypassword \
       -H "Content-Type: application/json" \
       http://localhost:5555/v1/services/haproxy/transactions/7d0d6737-655e-4489-92eb-6d29cdd69827


HAProxy :



frontend test_frontend
    mode http
    maxconn 2000
    bind *:80 name http
    acl is_example req.hdr(Host) example.com
    http-request deny deny_status 0 if { path /admin.php } !{ src 192.168.50.20/24 }
    use_backend example_servers if is_example
    default_backend test_backend

backend example_servers
    mode http
    balance roundrobin
    server server1 127.0.0.1:8081 check maxconn 30 weight 100

backend test_backend
    mode http
    balance roundrobin
    option httpchk HEAD / HTTP/1.1
    server server1 127.0.0.1:8080 check maxconn 30 weight 100




HAProxy Data Plane API, HAProxy REST API. (: https://habr.com/ru/post/508132/). , HAProxy API . Data Plane API , , HAProxy .



API . HAProxy .



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