Wow, sitting in the second row of the Dockercon Keynote today - there is so much new stuff in Docker 1.12! As a member of the Docker for Mac Beta program I got early access to Docker 1.12RC and pulled it down and updated my machine last night while waiting for Dockercon to start in Seattle. It was a 100MB update and my hotel WiFi is really fast (said nobody ever).
After updating I was still able to point at Docker 1.11 servers and run my previous workloads with the legacy Swarm version. YMMV, but do try the update.
I wanted to look at the new
docker service command. I'd seen a sneak preview of this from Mike Goelzer and tried to re-create from memory what he'd shown me about a week earlier.
Starting with a service
Let's pick a
service or a long running container. This could be the
sleep 500 command, but we can just as easily make it
Have a look at the new
docker service command's help page:
$ docker service Usage: docker service COMMAND Manage Docker services Options: --help Print usage Commands: create Create a new service inspect Inspect a service tasks List the tasks of a service ls List services rm Remove a service scale Scale one or multiple services update Update a service Run 'docker service COMMAND --help' for more information on a command.
docker service create
docker service create is synonymous with
docker run, so anything we can do with
docker run should work the same.
$ docker run busybox ping google.com PING google.com (220.127.116.11): 56 data bytes 64 bytes from 18.104.22.168: seq=0 ttl=37 time=0.527 ms 64 bytes from 22.214.171.124: seq=1 ttl=37 time=0.629 ms
Here's the equivalent command with
docker service create:
$ docker service create --name ping1 busybox ping docker.com 1hakvrpkl01zque7u17dxox41
I've assigned a name to the service so that we can reference it easily, but Docker has also generated a GUID of
docker service ls
To check which services we have running/created type in
docker service ls as below:
$ docker service ls ID NAME REPLICAS IMAGE COMMAND 1hakvrpkl01z ping1 1/1 busybox ping docker.com
docker service scale
Scaling this has never been easier, we just type in the name of the service and how many replicas we want.
$ docker service scale ping1=5 ping1 scaled to 5
We will now see that the
docker service ls command gives
5/5 replicas as running and
docker ps will show 5 unique containers running, too.
$ docker service ls ID NAME REPLICAS IMAGE COMMAND 1hakvrpkl01z ping1 5/5 busybox ping docker.com
docker scale rm
Once you have finished your work either scale back to 0 or remove the service with
docker service rm ping1
And so much more