Document updated on Nov 5, 2020
The Virtual Host plugin allows you to run different configurations of KrakenD endpoints based on the host accessing the server.
For instance, you can declare an endpoint /foo
that behaves entirely differently when KrakenD is accessed through a host-a.tld
or a host-b.tld
. For instance, the same /foo
path can have different rate limits or authorization endpoints depending on the called host.
On KrakenD EE the virtual host plugin usually lives inside the /plugins
folder. Include the following configuration in your krakend.json
to enable virtual hosts:
{
"version": 2,
"plugin": {
"pattern":".so",
"folder": "/opt/krakend/plugins/"
},
"extra_config": {
"github_com/devopsfaith/krakend/transport/http/server/handler": {
"name": ["virtualhost", ... ],
"virtualhost": {
"hosts": ["host-a.tld", "host-b.tld"]
}
}
}
}
As this is a plugin, there is a shared part in the configuration, such as the plugin
key, which defines all Enterprise or custom plugins’ location.
Secondly, as this is a router plugin, it uses the namespace github_com/devopsfaith/krakend/transport/http/server/handler
in the global extra_config
section, which is common to all router plugins.
Finally, all the router plugins that must be enabled are declared in the name
array. In this case, we want to allow the plugin virtualhost
.
The configuration keys of this plugin are stored under virtualhost
as follows:
host
: All recognized virtual hosts by KrakenD must be listed here. Use the value passed by the client as the Host
header.When you enable the virtual host plugin, all requests to KrakenD (/{path}
) that match with a recognized host
in the list are rewritten internally to /__virtual/{host}/{path}
.
Any request to a host that is not declared in the list does not have this redirection.
Given the following extra_config
configuration:
"extra_config": {
"github_com/devopsfaith/krakend/transport/http/server/handler": {
"name": ["virtualhost"],
"virtualhost": {
"hosts": ["host-a.yourserver.com", "host-b.yourserver.com"]
}
}
}
And the following endpoints
:
{
"version": 2,
"endpoints": [
{
"endpoint": "/foo",
"backend": [
{
"url_pattern": "/__debug/no-host",
"host": ["http://localhost:8080"]
}
]
},
{
"endpoint": "/__virtual/host-a.yourserver.com/foo",
"backend": [
{
"url_pattern": "/__debug/host-A",
"host": ["http://localhost:8080"]
}
]
},
{
"endpoint": "/__virtual/host-b.yourserver.com/foo",
"backend": [
{
"url_pattern": "/__debug/host-B",
"host": ["http://localhost:8080"]
}
]
}
]
}
You can check how /foo
hits different endpoints in the following order:
curl -i -H 'Host: anything' http://localhost:8080/foo
: No rewriting placed as host
is unknown. Hits the first endpoint.curl -i -H 'Host: host-a.yourserver.com' http://localhost:8080/foo
: Hits the second endpointcurl -i -H 'Host: host-b.yourserver.com' http://localhost:8080/foo
: Hits the third endpointThe documentation is only a piece of the help you can get! Whether you are looking for Open Source or Enterprise support, see more support channels that can help you.
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