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FileConfigurator Operator
The FileConfigurator operator allows configuring systems tuned by Akamas by interpolating configuration parameters into files on remote machines.
The operator performs the following operations:
- 1.It reads an input file from a remote machine containing templates for interpolating the configuration parameters generated by Akamas
- 2.It replaces the values of configuration parameters in the input file
- 3.It writes the file with replaced configuration parameters on a specified path on another remote machine
Access on remote machines is performed using SFTP (SSH).
The FileConfigurator allows writing templates for configuration parameters in two ways:
- specify that a parameter should be interpolated directly:
${component_name.parameter_name}
- specify that all parameters of a component should be interpolated:
${component_name.*}
It is possible to add a prefix or suffix to interpolated configuration parameters by acting at the component-type level:
Notice that any parameter that does not contain the FileConfigurator element in the operators' attribute is ignored and not written.
name: Component Type 1
description: My Component type
parameters:
- name: x1
domain:
type: real
domain: [-5.0, 10.0]
defaultValue: -5.0
# Under this section, the operator to be used to configure the parameters is defined
operators:
FileConfigurator:
# using this OPTIONAL confTemplate property is possible to interpolate the parameter value with a prefix and a suffix
confTemplate: "PREFIX${value}SUFFIX"
In the example above, the parameter
x1 will be interpolated with the prefix PREFIX and the suffix SUFFIX, ${value} will be replaced with the actual value of the parameter at each experiment.Let's assume we want to apply the following configuration:
component1.param1: 1024
component1.param2: Category1
component2.param3: 7
component2.param4: 35.4
where
component1 is of type MyComponentType and MyComponentType is defined as follows:name: MyComponentType
description: "MyComponentType
parameters:
- name: param1
domain:
type: real
domain: [-5.0, 10.0]
defaultValue: -5.0
# Under this section, the operator to be used to configure the parameters is defined
operators:
FileConfigurator:
# using this OPTIONAL confTemplate property is possible to interpolate the parameter value with a prefix and a suffix
confTemplate: "X1:${value}MB"
...
A template file to interpolate only parameter
component1.param1 and all parameters from component2 would look like this:myexecutable.sh -PARAM ${component1.param1} -PARAMS ${component2.*}
The file after the configuration parameters are interpolated would look like this:
myexecutable.sh -PARAM X1:1024MB -PARAMS 7 35.4
Note that the file in this example contains a bash command whose arguments are constructed by interpolating configuration parameters. This represents a typical use case for the File Configurator: to construct the right bash commands that will configure a system with the new configuration parameters computed by Akamas.
Name | Type | Value Restrictions | Required | Default | Description |
|---|---|---|---|---|---|
source | Object | should have a structure like the one defined in the next section | no, if the Component whose name is defined in component has properties that map to the ones defined within source | | Information relative to the source/input file to be used to interpolate optimal configuration parameters discovered by Akamas |
target | Object | should have a structure like the one defined in the next section | no, if the Component whose name is defined in component has properties that map to the ones defined within target | | Information relative to the target/output file to be used to interpolate optimal configuration parameters discovered by Akamas |
component | String | should match the name of an existing Component of the System under test | no | | The name of the Component whose properties can be used as arguments of the operator |
ignoreUnsubstitutedTokens | Boolean | | no | False | Behavior of the operator regarding leftover tokens in the target file.
When False, FileConfigurator fails.
When True , FileConfigurator succeeds regardless of leftover tokens |
Here follows the structure of either the
source or target operator argumentName | Type | Value restrictions | Required | Default | Description |
|---|---|---|---|---|---|
hostname | String | should be a valid SSH host address | yes | | SSH endpoint |
username | String | | yes | | SSH login username |
password | String | cannot be set if key is already set | no | | SSH login password |
sshPort | Number | 1≤ sshPort≤65532 | no | 22 | SSH port |
key | String | cannot be set if password is already set | no | | SSH login key, provided directly its value or the path of the file to import from. The operator supports RSA and DSA Keys |
path | String | should be a valid path | yes | | The path of the file to be used either as the source or target of the activity to applying Akamas computed configuration parameters using files |
The
component argument can be used to refer to a component by name and use its properties as the arguments of the operator. In case the mapped arguments are already provided to the operator, there is no override.In this case, the operator replaces in the template file only tokens referring to the specified component. A parameter bound to any component will cause the substitution to fail.
Component property | Operator argument |
|---|---|
hostname | source->hostname target->hostname |
username | source->username target->username |
sshPort | source->sshPort target->sshPort |
password | source->password target->password |
key | source->key target->key |
sourcePath | source->path |
targetPath | target->path |
name: RemoteConfOperatorTestStandalone
operator: FileConfigurator
arguments:
source:
hostname: template-server
username: akamas-user1
password: akamas-password1
path: /templates/frontend-httpd.conf
target:
hostname: frontend-server
username: akamas-user2
password: akamas-password22
path: /etc/httpd/httpd.conf
name: RemoteConfOperatorTestStandalone
operator: FileConfigurator
arguments:
component: apache-server-1
where the
apache-server-1 component is defined as:name: apache-server-1
description: The Apache server instance
componentType: Apache Server 2.4
properties:
hostname: apache.akamas.io
username: ubuntu
key: key.pem
sourcePath: templates/httpd.conf.template
targetPath: /etc/httpd/httpd.conf
Last modified 3d ago