docker service scale

Swarm This command works with the Swarm orchestrator.

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.

Options

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