pinger

appcelerator/pinger

Simple service for demo purposes. Responds with pong to a GET request at: http://<host>:<port>/ping, and logs to stdout.

Running pinger

$ docker run -it --rm -p 3000:3000 --name pinger appcelerator/pinger

or

$ docker service create -p 3000:3000 --name pinger appcelerator/pinger

Scaling pinger

Try scaling scaling pinger up

$ docker service scale pinger=3

Confirm all the replicas are running as the service scales to the desired amount

$ docker service 
$ docker service ls --filter name=pinger
ID            NAME    REPLICAS  IMAGE                COMMAND
bfjh7nervm3z  pinger  3/3       appcelerator/pinger

Then test

$ curl localhost:3000/ping
[f0afaf6c5ea5] pong

Each time you curl, you should see a different hostname in the brackets of the response as Docker automatically load balances requests among all the service replicas.

Note

Because HTTP/1.1 defaults to persistent connections, to assure the same result for demo purposes in the browser, the ping service closes the HTTP connection with each response by setting Connection: close in the response header.

Development

build.sh - builds an alpine-based image: appcelerator/pinger

run.sh - convenience script for docker run ...

service-start.sh - convenience script for docker service create ...

service-stop.sh - convenience script for docker service rm ...