Upstream

Description

Upstream is a virtual host abstraction that performs load balancing on a given set of service nodes according to the configured rules.

Although Upstream can be directly configured to the Route or Service, using an Upstream object is recommended when there is duplication as shown below.

By creating an Upstream object and referencing it by upstream_id in the Route, you can ensure that there is only a single value of the object that needs to be maintained.

An Upstream configuration can be directly bound to a Route or a Service, but the configuration in Route has a higher priority. This behavior is consistent with priority followed by the Plugin object.

Configuration

In addition to the equalization algorithm selections, Upstream also supports passive health check and retry for the upstream. You can learn more about this here.

To create an Upstream object, you can use the Admin API as shown below:

curl http://127.0.0.1:9080/apisix/admin/upstreams/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "type": "chash",
    "key": "remote_addr",
    "nodes": {
        "127.0.0.1:80": 1,
        "foo.com:80": 2
    }
}'

After creating an Upstream object, it can be referenced by a specific Route or Service as shown below:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/index.html",
    "upstream_id": 1
}'

For convenience, you can directly bind the upstream address to a Route or Service:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/index.html",
    "plugins": {
        "limit-count": {
            "count": 2,
            "time_window": 60,
            "rejected_code": 503,
            "key": "remote_addr"
        }
    },
    "upstream": {
        "type": "roundrobin",
        "nodes": {
            "127.0.0.1:1980": 1
        }
    }
}'

Example

The example below shows how you can configure a health check:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/index.html",
    "plugins": {
        "limit-count": {
            "count": 2,
            "time_window": 60,
            "rejected_code": 503,
            "key": "remote_addr"
        }
    },
    "upstream": {
         "nodes": {
            "127.0.0.1:1980": 1
        }
        "type": "roundrobin",
        "retries": 2,
        "checks": {
            "active": {
                "http_path": "/status",
                "host": "foo.com",
                "healthy": {
                    "interval": 2,
                    "successes": 1
                },
                "unhealthy": {
                    "interval": 1,
                    "http_failures": 2
                }
            }
        }
    }
}'

You can learn more about health checks here.

The examples below show configurations that use different hash_on types.

Consumer

Creating a Consumer object:

curl http://127.0.0.1:9080/apisix/admin/consumers -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "username": "jack",
    "plugins": {
       "key-auth": {
            "key": "auth-jack"
        }
    }
}'

Creating a Route object and enabling the key-auth authentication Plugin:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "plugins": {
        "key-auth": {}
    },
    "upstream": {
        "nodes": {
            "127.0.0.1:1980": 1,
            "127.0.0.1:1981": 1
        },
        "type": "chash",
        "hash_on": "consumer"
    },
    "uri": "/server_port"
}'

To test the request, the consumer_name passed for authentication will be used as the hash value of the load balancing hash algorithm.

curl http://127.0.0.1:9080/server_port -H "apikey: auth-jack"

Cookie

Creating a Route and an upstream object:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/hash_on_cookie",
    "upstream": {
        "key": "sid",
        "type ": "chash",
        "hash_on ": "cookie",
        "nodes ": {
            "127.0.0.1:1980": 1,
            "127.0.0.1:1981": 1
        }
    }
}'

The client can then send a request with a cookie:

 curl http://127.0.0.1:9080/hash_on_cookie -H "Cookie: sid=3c183a30cffcda1408daf1c61d47b274"

Header

Creating a Route and an upstream object:

curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
    "uri": "/hash_on_header",
    "upstream": {
        "key": "content-type",
        "type ": "chash",
        "hash_on ": "header",
        "nodes ": {
            "127.0.0.1:1980": 1,
            "127.0.0.1:1981": 1
        }
    }
}'

The client can now send requests with a header. The example below shows using the header Content-Type:

 curl http://127.0.0.1:9080/hash_on_header -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -H "Content-Type: application/json"