API Gateway Quiesce Mode

About this task

You must perform this operation in the old API Gateway instance.

Quiescing API Gateway temporarily disables access to the API Gateway server. When the API Gateway server access is disabled, you can perform the required upgrade tasks while the API Gateway server is not connected to any external resources. For more information on quiesce mode, see Quiesce Mode.

While flushing the performance, license, and quota metrics data, API Gateway performs the following operations:

Resets performance and license metrics intervals for all the APIs and stores the data in the Elasticsearch or API Data Store.
Stores the subscription quota in the Elasticsearch or API Data Store.

When all the performance metrics and other data are flushed completely, quiesce mode is enabled for all the API Gateway nodes, and a notification is sent through a webhook event.

To operate API Gateway in quiesce mode, execute the following steps:

Procedure

Create a quiesce port.
Before you invoke the quiesce mode, you must create a quiesce port, and enable it in the old API Gateway instance.

You can use the following request to create and enable the quiesce port.
```
POST /rest/apigateway/ports
{
    "factoryKey": "webMethods/HTTP",
    "pkg": "WmRoot",
    "port": "4444",
    "portAlias": "QuiescePort"
}
```
In the example above, the 4444 port is used.

Once you create the port, use the following request to enable the quiesce port.
```
PUT rest/apigateway/ports/enable
{
    "listenerKey": "HTTPListener@4444",
    "pkg": "WmRoot",
    "requestServiceStatus": ""
}
```
After the quiesce port is enabled, use the following request to set the quiesce port. You must use the same portAlias value that you used while creating the quiesce port. In this example, the portAlias used while creating the quiesce port is QuiescePort.
```
PUT invoke/wm.API Gateway server.quiesce/setQuiescePort
{
    "portAlias": "QuiescePort"
}
```

Enable or disable the quiesce mode.

You can use the following request to enable or disable the quiesce mode.

PUT /rest/apigateway/quiescemode
{
    "enable": "true/false",
    "block": "designtime/all",
    "flush": [
        "license_metrics",
        "performance_metrics",
        "subscription_quota"
    ]
}

The parameters used in the above request are described in the following table:

Parameter	Description
enable	Set the enable parameter as `true` to enable quiesce mode and `false` to disable the quiesce mode. You can disable the quiesce mode only when the block parameter is set as `designtime`. When the block parameter is set as `all`, API Gateway is quiesced and is unreachable. Hence, you cannot disable the API Gateway quiesce mode by invoking this request.
block	Set the block parameter as `designtime` to block only design time requests and `all` to block all the requests.
flush	This parameter is not applicable when you set the block parameter as `designtime`. The flush parameter is applicable only when you set the block parameter as `all`. In the above example, when you set the block parameter as `all`, API Gateway blocks all the requests and flushes the license metrics, performance metrics, and the subscription quota data. If you do not specify any value in this parameter, all the data is flushed.

Retrieving the quiesce mode status.
Apart from the webhook notification of the quiesce mode status, you can use the following request to retrieve the quiesce mode status.
```
GET /rest/apigateway/quiescemode
```
Response
```
{
    "enable": "true/false",
    "block": "designtime/all",
    "flush": [
        "license_metrics",
        "performance_metrics",
        "subscription_quota"
    ],
    "status": "success",
    "failureReason": null
}
```
Note: This request works only for quiesce mode for designtime. This request will not work for all, because the API Gateway package is disabled when you invoke quiesce mode for all. In such cases, you must invoke the API Gateway health check API through the quiesce port. If it returns a status code other than 200 or no response, then the quiesce mode for all is completed in that node successfully.