Component Spec Requirements

The component specification contains the following groups of information.

Metadata
Interfaces including the associated Data Formats
Parameters
Auxiliary Details
List of Artifacts

Auxiliary Details

auxiliary contains Docker specific details like health check, port mapping, volume mapping and policy reconfiguration script details.

Name	Type	Description
healthcheck	JSON object	Required. Health check definition details
ports	JSON array	each array item maps a container port to the host port. See example below.
volumes	JSON array	each array item contains volume definition of either: host path or config map volume.
policy	JSON array	Required. Policy reconfiguration script details
tls_info	JSON object	Optional. Information about usage of tls certificates

Health Check Definition

The platform currently supports http and docker script based health checks.

When choosing a value for interval, consider that too frequent healthchecks will put unnecessary load on the platform. If there is a problematic resource, then more frequent healthchecks are warranted (eg 15s or 60s), but as stability increases, so can these values, (eg 300s).

When choosing a value for timeout, consider that too small a number will result in increasing timeout failures, and too large a number will result in a delay in the notification of the resource problem. A suggestion is to start with 5s and work from there.

http

Property Name	Type	Description
type	string	Required. `http`
interval	string	Interval duration in seconds i.e. `60s`
timeout	string	Timeout in seconds i.e. `5s`
endpoint	string	Required. GET endpoint provided by the component for checking health

Example:

"auxilary": {
    "healthcheck": {
        "type": "http",
        "interval": "15s",
        "timeout": "1s",
        "endpoint": "/my-health"
    }
}

docker script example

Property Name	Type	Description
type	string	Required. `docker`
interval	string	Interval duration in seconds i.e. `15s`
timeout	string	Timeout in seconds i.e. `1s`
script	string	Required. Full path of script that exists in the Docker container to be executed

During deployment, the K8S plugin maps the healthcheck defined into into a Kubernetes readiness probe.

Kubernetes execs the script in the container (using the docker exec API ). It will examine the script result to identify whether your component is healthy. Your component is considered healthy when the script returns 0 otherwise your component is considered not healthy.

Example:

"auxilary": {
    "healthcheck": {
        "type": "docker",
        "script": "/app/resources/check_health.py",
        "timeout": "30s",
        "interval": "180s"
    }
}

Ports

This method of exposing/mapping a local port to a host port is NOT RECOMMENDED because of the possibility of port conflicts. If multiple instances of a docker container will be running, there definitely will be port conflicts. Use at your own risk. (The preferred way to expose a port is to do so in the Dockerfile as described here).

"auxilary": {
    "ports": ["8080:8000"]
}

In the example above, container port 8080 maps to host port 8000.

Volume Mapping

"auxilary": {
    "volumes": [
        {
           "container": {
               "bind": "/tmp/docker.sock",
               "mode": "ro"
            },
            "host": {
                "path": "/var/run/docker.sock"
            }
        },
        {
           "container": {
               "bind": "/tmp/mount_path"
               "mode": "ro"
            },
            "config_volume": {
                "name": "config_map_name"
            }
        }
    ]
}

At the top-level:

Property Name	Type	Description
volumes	array	Contains container with host/config_volume objects

The container object contains:

Property Name	Type	Description
bind	string	path to the container volume
mode	string	ro - indicates read-only volume
		w - indicates that the contain can write into the bind mount

The host object contains:

Property Name	Type	Description
path	string	path to the host volume

The config_volume object contains:

Property Name	Type	Description
name	string	name of config map

Here is an example of the minimal JSON with host path volume that must be provided as an input:

"auxilary": {
    "volumes": [
        {
           "container": {
               "bind": "/tmp/docker.sock"
            },
            "host": {
                "path": "/var/run/docker.sock"
            }
        }
    ]
}

In the example above, the container volume “/tmp/docker.sock” maps to host volume “/var/run/docker.sock”.

Here is an example of the minimal JSON with config map volume that must be provided as an input:

"auxilary": {
    "volumes": [
        {
           "container": {
               "bind": "/tmp/mount_path"
            },
            "config_volume": {
                "name": "config_map_name"
            }
        }
    ]
}

In the example above, config map named “config_map_name” is mounted at “/tmp/mount_path”.

Policy

Policy changes made in the Policy UI will be provided to the Docker component by triggering a script that is defined here.

Property Name	Type	Description
reconfigure_type	string	Required. Current value supported is `policy`
script_path	string	Required. Current value for ‘policy’ reconfigure_type must be “/opt/app/reconfigure.sh”

Example:

"auxilary": {
    "policy": {
        "reconfigure_type": "policy",
        "script_path": "/opt/app/reconfigure.sh"
    }
}

The docker script interface is as follows: `/opt/app/reconfigure.sh $reconfigure_type {“updated policies”: , “application config”: }

Name	Type	Description
reconfigure_type	string	policy
updated_policies	json	TBD
updated_appl_config	json	complete generated app_config, not fully-resolved, but `policy-enabled` parameters have been updated. In order to get the complete updated app_config, the component would have to call `config-binding-service`.

TLS Info

TLS Info is used to trigger addition of init containers that can provide main application containers with certificates for internal and external communication.

Property Name	Type	Description
cert_directory	string	Required. Directory where certificates should be created. i.e. `/opt/app/dcae-certificate`
use_tls	boolean	Required. A boolean that indicates whether server certificates for internal communication should be added to the main container i.e `true`
use_external_tls	boolean	Optional. A boolean that indicates whether the component uses OOM CertService to acquire operator certificate to protect external (between xNFs and ONAP) traffic. For a time being only operator certificate from CMPv2 server is supported. i.e `true`

Example:

"auxilary": {
        "tls_info": {
                "cert_directory": "/opt/app/dcae-certificate",
                "use_tls": true
                "use_external_tls": true,
        }
},

Docker Component Spec - Complete Example

{
    "self": {
        "version": "1.0.0",
        "name": "yourapp.component.kpi_anomaly",
        "description": "Classifies VNF KPI data as anomalous",
        "component_type": "docker"
    },
    "streams": {
        "subscribes": [{
            "format": "dcae.vnf.kpi",
            "version": "1.0.0",
            "route": "/data",
            "type": "http"
        }],
        "publishes": [{
            "format": "yourapp.format.integerClassification",
            "version": "1.0.0",
            "config_key": "prediction",
            "type": "http"
        }]
    },
    "services": {
        "calls": [{
            "config_key": "vnf-db",
            "request": {
                "format": "dcae.vnf.meta",
                "version": "1.0.0"
                },
            "response": {
                "format": "dcae.vnf.kpi",
                "version": "1.0.0"
                }
        }],
        "provides": [{
            "route": "/score-vnf",
            "request": {
                "format": "dcae.vnf.meta",
                "version": "1.0.0"
                },
            "response": {
                "format": "yourapp.format.integerClassification",
                "version": "1.0.0"
                }
        }]
    },
    "parameters": [
        {
            "name": "threshold",
            "value": 0.75,
            "description": "Probability threshold to exceed to be anomalous"
        }
    ],
    "auxilary": {
        "healthcheck": {
            "type": "http",
            "interval": "15s",
            "timeout": "1s",
            "endpoint": "/my-health"
        }
    },
    "artifacts": [{
        "uri": "fake.nexus.att.com/dcae/kpi_anomaly:1.0.0",
        "type": "docker image"
    }]
}