A manifest is a JSON file that describes a ConPaaS application. It can be written with your favourite text editor, or automatically generated from a running ConPaaS application.
Here is manifest for an application that will run a simple PHP program (a free sudoku PHP program). File sudoku.mnf:
{
"Application" : "Sudoku example",
"Services" : [
{
"ServiceName" : "PHP sudoku backend",
"Type" : "php",
"Start" : 0,
"Archive" : "http://www.conpaas.eu/wp-content/uploads/2011/09/sudoku.tar.gz"
}
]
}
This simple example states the application name and the service list which is here a single PHP service. It gives the name of the service, its type, whether it should be automatically started (1 for autostart, 0 otherwise), and it gives the path to the PHP program that will be uploaded into the created PHP service.
To create an application from a manifest, you can use either the web client or the command line client.
On the web client, after login, press button “deploy ready-made application”, then press button “Browse...” and select your sudoku.mnf. A popup will appear to confirm that the creation of the application has started.
On the command line, you can simply run:
cpsclient.py manifest sudoku.mnf
In this example, once the application has been created, you will have to start the PHP service either with the web client (button start on the PHP service page) or with command line client (cpsclient.py start <php_serv_id>).
On the ConPaaS website there is a short video (http://www.youtube.com/watch?v=kMzx8sgr96I) that shows how to setup a MediaWiki installation using the ConPaaS frontend. In this section we are going to create a manifest file that replicates exactly the same MediaWiki application shown in the video:
{
"Application" : "Wiki in the Cloud",
"Services" : [
{
"ServiceName" : "Wiki-Webserver",
"Type" : "java",
"Archive" : "http://mywebsite.com/scalaris-wiki.war",
"StartupInstances" :
{
"proxy" : "1",
"web" : "1",
"backend" : "5"
},
"Start" : 1
},
{
"ServiceName" : "Wiki-Database",
"Type" : "scalaris",
"Archive" : "http://mywebsite.com/wikipediadump",
"Start" : 1
}
]
}
Even if the application is more complicated than the sudoku, the manifest file is not very different. In this case the file specifies two different services: Java and Scalaris (which is a NoSQL database). Also, given that the service might receive lots of traffic, 5 instances of the Java backend are started. In the presentation the Java instances are added later, but in this example to show how the StartupInstances works, 5 Java virtual machines are started from the beginning. Unfortunately the option of choosing a static IP for the database is not yet available, so we cannot specify it in the Java service at startup.
You can generate a manifest from an existing ConPaaS application with command line client:
cpsclient.py download_manifest appl_id > myappl.mnf
You can edit the generated manifest myappl.mnf to your liking. Then you can create a new application with this manifest:
cpslient.py manifest myappl.mnf
Note: in ConPaaS 1.3.1, you cannot get a manifest of an existing application through the web client. It’s only available through the command line client or through the API.
In this section, we present the complete description of all the possible fields that can be used in the manifest. We will also distinguish between required and optional fields. Currently, the available service types are:
These are the required fields for each service
If nothing else is specified in the manifest the service will have the default name and it will not be started.
The following fields are optional and are available in all the services.
It is not required to define how many instances the service needs. By default if the user starts a service, one instance will be created. If the user wants to create more instances, then the user can use this option in the manifest.
This will be an object that can contain different fields. All the possible fields that can be specified for each service are described in the following table:
| Service | Type |
|---|---|
| php | proxy, web, backend |
| java | proxy, web, backend |
| mysql | slaves |
| scalaris | scalaris |
| hadoop | workers |
| selenium | node |
| xtreemfs | osd |
Next, I’ll show all the manifest fields that are specific for each service.
Other fields are optional and are not service-specific, but manifest-specific instead, so they need to be specified on top of the file (see the full example in the end) are the following:
This example is a full specification file with all the possible options available:
{
"Description" : "Description of the project",
"Application" : "New full application"
"Services" : [
{
"ServiceName" : "Meaningful PHP service name",
"Type" : "php",
"Cloud" : "default",
"Start" : 0,
"Archive" : "http://mywebsite.com/archive.tar.gz",
"StartupInstances" : {
"proxy" : "1",
"web" : "1",
"backend" : "1"
}
},
{
"ServiceName" : "Meaningful Java service name",
"Type" : "java",
"Cloud" : "default",
"Start" : 0,
"Archive" : "http://mywebsite.com/project.war",
"StartupInstances" : {
"proxy" : "1",
"web" : "1",
"backend" : "1"
}
},
{
"ServiceName" : "Meaningful MySQL service name",
"Type" : "mysql",
"Cloud" : "default",
"Start" : 0,
"Dump" : "http://mywebsite.com/dump.sql",
"StartupInstances" : {
"slaves" : "1"
}
},
{
"ServiceName" : "Meaningful Scalaris service name",
"Type" : "scalaris",
"Cloud" : "default",
"Start" : 0,
"StartupInstances" : {
"scalaris" : "1"
}
},
{
"ServiceName" : "Meaningful Hadoop service name",
"Type" : "hadoop",
"Cloud" : "default",
"Start" : 0,
"StartupInstances" : {
"workers" : "1"
}
},
{
"ServiceName" : "Meaningful Selenium service name",
"Type" : "selenium",
"Cloud" : "default",
"Start" : 0,
"StartupInstances" : {
"node" : "1"
}
},
{
"ServiceName" : "Meaningful XtreemFS service name",
"Type" : "xtreemfs",
"Cloud" : "default",
"Start" : 0,
"VolumeStartup" : {
"volumeName" : "Meaningful volume name",
"owner" : "volumeowner"
},
"StartupInstances" : {
"osd" : "1"
}
}
]
}