Setting Priority Values for Starting Services

Use this feature to control the order in which services are started in the Edge iNode.

Strict Dependency

You can use priority values 3 and 4 to assign application service startup priority to introduce a strict dependency between services.

By strict priority setting, the services in the lower-priority bucket will start only after starting all services in the high- priority bucket. For example, services in priority bucket 4 will start after all services in priority bucket 3 start.

Soft Dependency

You can use priority values 5 and 6 to assign application service startup priority to introduce soft dependency between services.

By soft priority setting, the services in the lower-priority bucket will start after waiting for a preset timeout period for all services in the high-priority bucket to start. For example, the services in priority bucket 6 will start after waiting for a preset timeout (15 seconds) for all services in priority bucket 5 to start.

No Dependency

You can use priority value 7 to specify a service priority that has no dependencies on any other service. A service with priority 7 can start in any order, regardless of the service state of priority buckets between 3 and 6.

Creating a Service Priority

You can create a custom service with the label io_iotium_pod_priority using values between 3 and 7.

Example:

{
	"name": "svcName",
	"labels": {
		"io_iotium_pod_priority":"7"
	},
	"services": [{
		"image": {
			"name": "iotium/svcImage",
			"version": "latest"
		},
		"docker": {
			"environment_vars": {
				"TIMEOUT": "1",
			}
		}
	}]
}