Nodepinger is a simple typescript nodejs application which performs "TCP Ping" - basically establishing a TCP connection on a given port then dropping it.
The intention is to measure the time it takes for this operation as precisely as possible.
To that end - it performs its task in two modes:
ip: the targets.json list of targets are pre-resolved with DNS so that this is not required to establish the connection.
dns: the ip of the target is resolved prior to each "ping".
Both metrics are recorded and available for scraping for each target (excepting ip-only targets)
The configuration of nodepinger is as a) a set of targets and b) a set of environment variables which governs its operation.
NOTE: For the kubernetes deployment, it is presumed that you manage a single "targets" configmap as this is usually run in conjunction with
readychecker. If this is not the case, take the
Readychecker expects targets.json to exist in the destination subfolder relative to its execution.
Its format is as an array of json objects, thus:
[{
"Customer": "Generic", // string, descriptive name. Typically used as top-level indicator for a group of targets
"Deployment": "Google", // string, descriptive name. Typically used as a second-level indactor for a group of targets
"Mode": "prod", // enum: "dev"|"stage"|"prod" - indicates the mode of the target.
"Region": "global", // string, descriptive name. Typically used to indicate multiple regional instances of a customer+deployment for the selected mode.
"URL": "https://google.com" // URL - the target to check.
}]NOTE: This has not been tested with spaces in the customer/deployment/mode/region fields, so it would be advisable to avoid that for the time being (or test yourself.).
The operation is governed by the following environment variables:
| Variable | Default | Description |
|---|---|---|
| SOURCE_REGION | "local" | Indication of the region where the nodepinger is run from, follows the "Region" convention of targets.json |
| PING_FREQUENCY_SECONDS | 10 | How many seconds between each time a target is pinged |
| PING_PARALLELISM | 5 | How many connections are allowed to be in-flight at any given moment |
| PING_TIMEOUT_MILLISECONDS | 2500 | How many milliseconds should we wait for a connection to be established before it is timed out |
The included dockerfile is extremely basic, but sufficient for the purpose.
The nodepinger is intended to be run in a kubernetes cluster as a deployment. It is also sensible to run alongside the readycheck tool which performs end-to-end http requests - and would be reading the same target list.
It is also designed to automatically reload targets if the configmap changes contents.
As such, the included deploy folder contains the Deployment and Service - the configmap is in the readycheck deployment.yaml
The docker image is not publicly published, so you would need to build and push it to a registry of your choice, and modify the path & name of the image of the container in the deployment spec.