## 4.1.8.1.8.4.1  Service Instance Parameters
Some services support additional configuration parameters in the create-service or update-service request. These parameters are parsed in a valid JSON object containing the service-specific configuration parameters.
The deploy service supports the following methods for the specification of service instance parameters:
- Method A - an entry in the MTA deployment descriptor or the extension
- Method B - a JSON file with the required service configuration parameters
##  Note
If service instance information is supplied both in the deployment (or extension) descriptor and in a supporting JSON file, the parameters specified directly in the deployment (or extension) descriptor override the parameters specified in the JSON file.
Service instance parameters - method comparison
## Method A
##  Sample Code
```
MTA deployment descriptor or extension resources: - name: java-uaa type: com.sap.xs.uaa parameters: config: xsappname: java-hello-world
```
## Method B
##  Sample Code
```
MTA deployment
```
```
descriptor or extension resources: - name: java-uaa type: com.sap.xs.uaa
```
##  Sample Code xs-security.json "xsappname": "java-
```
{ hello-world" }
```
##  Sample Code Additional entry in MANIFEST.MF
```
Name: xsMTA-Resource: java-
```
```
security.json uaa Content-Type: application/json
```
## Combination of the two methods
##  Sample Code
```
resources: - name: java-uaa type: com.sap.xs.uaa parameters: path: <path to directory> config: xsappname: java-hello-world
```
##  Sample Code
```
xs-security.json { "xsappname": "javahello-world" }
```
##  Sample Code
```
Additional entry in MANIFEST.MF Name: xssecurity.json MTA-Resource: javauaa Content-Type: application/json
```
Using method A, all parameters under the special config parameter are used for the service creation or the service update request. This parameter is optional.
##  Tip
You can use the optional path parameter to navigate to a JSON file containing service-specific parameters and configurations. The content of the file is used for the creation or update of the service instance.
Note that if you are deploying from a local directory using an mtad.yaml , it needs to contain the path to the JSON file, so that the relevant MANIFEST.MF entry is generated.
##  Note
The path parameter only works when deploying from directory or when it is specified in the development descriptor mta.yaml . It is used only in build time and not during runtime (deployment).
Using method B, there are dependencies on further configuration entries in other configuration files. For example, if you use this JSON method, an additional entry must be included in the MANIFEST.MF file which
defines the path to the JSON file containing the parameters as well as the name of the resource for which the parameters should be used.
## Updating Service Instance Parameters
## Only valid for service instances managed by service brokers
Updating service instance parameters is, by default, fail-safe for those operations which result in a call to the service brokers. You can control this behavior by using the fail-on-service-update parameter.
Possible values for the parameter are:
- null (default value): If the update triggers an asynchronous operation (Cloud Controller sends the parameters to the service broker), the deployment will not fail even if the operation fails.
- true : If the update of the service parameters fails (even asynchronously), the deployment will also fail.
- false : The update becomes even more permissive - even if the initial call to update the service parameters fails, the deployment will still continue.
```
 Example parameters: fail-on-service-update: parameters: true
```
## Only valid for user-provided service instances
The update of the user-provided service instance parameters is not fail-safe by default (because no service brokers are involved). All update operations for user-provided service instances are synchronous . Y ou can control this behavior by using the fail-on-service-update parameter.
Possible values for the parameter are:
- null (default value): If the update of the service parameters fails, the deployment will also fail (same behavior as when set to true)
- true : If the update of the service parameters fails, the deployment will also fail.
- false : The update becomes permissive - even if the call to the Cloud Controller fails, the deployment will still continue.
## 
```
Example parameters: fail-on-service-update: parameters: true
```
## Related Information
Standalone Application Router - HTML5 Application Repository Managing Service Instances with the cf CLI