2.8 KiB
service scale
Scale one or multiple replicated services
Options
| Name | Type | Default | Description |
|---|---|---|---|
-d, --detach |
bool |
Exit immediately instead of waiting for the service to converge |
Description
The scale command enables you to scale one or more replicated services either up or down to the desired number of replicas. This command cannot be applied on services which are global mode. The command will return immediately, but the actual scaling of the service may take some time. To stop all replicas of a service while keeping the service active in the swarm you can set the scale to 0.
[!NOTE] This is a cluster management command, and must be executed on a swarm manager node. To learn about managers and workers, refer to the Swarm mode section in the documentation.
Examples
Scale a single service
The following command scales the "frontend" service to 50 tasks.
$ docker service scale frontend=50
frontend scaled to 50
The following command tries to scale a global service to 10 tasks and returns an error.
$ docker service create --mode global --name backend backend:latest
b4g08uwuairexjub6ome6usqh
$ docker service scale backend=10
backend: scale can only be used with replicated or replicated-job mode
Directly afterwards, run docker service ls, to see the actual number of
replicas.
$ docker service ls --filter name=frontend
ID NAME MODE REPLICAS IMAGE
3pr5mlvu3fh9 frontend replicated 15/50 nginx:alpine
You can also scale a service using the docker service update
command. The following commands are equivalent:
$ docker service scale frontend=50
$ docker service update --replicas=50 frontend
Scale multiple services
The docker service scale command allows you to set the desired number of
tasks for multiple services at once. The following example scales both the
backend and frontend services:
$ docker service scale backend=3 frontend=5
backend scaled to 3
frontend scaled to 5
$ docker service ls
ID NAME MODE REPLICAS IMAGE
3pr5mlvu3fh9 frontend replicated 5/5 nginx:alpine
74nzcxxjv6fq backend replicated 3/3 redis:7.4.1